Rotor for a turbomachine, turbomachine, and method for balancing a rotor of a turbomachine

Abstract

The invention relates to a rotor (10) for a turbomachine. The rotor comprises a rotor nose (11) having an integral balance geometry (12) for material removal for balancing purposes. The balance geometry (12) has a first balance portion (121) having a first center of mass (S1) and a second balance portion (122) having a second center of mass (S2), wherein the first center of mass (S1) and the second center of mass (S2) are mutually axial spaced. The invention also relates to a turbomachine having a rotor of this kind, and to a method for balancing a rotating assembly of a turbomachine having a rotor. According to an alternative embodiment, the balance geometry has an outer surface for a first material-removal process and an inner surface for a second material-removal process for balancing purposes. The outer surface has a greater radial distance from an axis of rotation of the rotor than the inner surface.

Description

ROTOR FOR A TURBOMACHINE, TURBOMACHINE, AND METHOD FOR BALANCING A ROTOR OF A TURBOMACHINE TECHNICAL FIELD

[0001] The invention relates to the field of turbomachines, in particular rotors for turbomachines, and to the field of balancing, in particular the balancing of rotors and running gears of turbomachines. TECHNICAL BACKGROUND

[0002] Today, exhaust gas turbochargers are standard equipment for increasing the performance of internal combustion engines. They consist of a turbine in the engine's exhaust system and a compressor upstream of the engine. The exhaust gases from the engine are expanded in the turbine. The resulting work is transferred via a shaft to the compressor, which compresses the air supplied to the engine. By using the energy from the exhaust gases to compress the air supplied to the combustion process in the engine, the combustion process and the efficiency of the engine can be optimized.

[0003] Exhaust gas turbochargers essentially consist of a turbine wheel and a compressor wheel, with the turbine wheel being welded to a shaft, after which the compressor wheel is attached on the opposite side.

[0004] Due to the inevitable deviations in shape and material structure that occur during the manufacturing process, mass deviations in relation to the rotor axis result, which are generally a combination of a static Unbalance and moment unbalance are referred to as dynamic unbalance. During the further assembly process of the turbine rotor and the core assembly, further unbalances arise due to the additionally threaded, unbalanced individual parts, the shape, position, and fit tolerances, as well as any plasticization in the shaft assembly and shaft thread.

[0005] During operation, i.e., when the rotor rotates, these imbalances lead to circulating centrifugal forces, which ideally increase quadratically with the speed for rotors with rigid behavior. For rotors with wave-elastic behavior, this can result in excitation of the critical bending mode, which in turn leads to high forces that stress the bearing system. To avoid exceeding the maximum bearing load capacity under all operating conditions and thus ensure the intended service life of the turbochargers, they are tested for imbalance in a process that usually involves several stages. If necessary, a mass balance is performed until the predefined limits are met.

[0006] The balancing process is simpler for compressor wheels than for turbine wheels, as they are less prone to imbalance due to a simpler manufacturing process and the material can be machined with minimal tool wear. If necessary, compressor wheels can also be installed on the turbocharger without separate balancing of individual parts.

[0007] In turbine rotors, the imbalance results almost entirely from the welded turbine wheel, making balancing unavoidable due to the high dimensional deviations of the blanks. To reduce input imbalance, balancing centering processes are often used in turbine wheel machining to reduce rotor balancing costs and keep the geometric balance margin within limits.

[0008] To compensate for dynamic imbalances, two compensation planes with sufficient axial distance from each other are generally required. For this purpose, the so-called nose planes are used in combination with the respective wheel disc or wheel back plane. The running gear is then checked for imbalance, either before or after core assembly, and material removal, if necessary, is performed on at least one but no more than two additional compensation planes.

[0009] In total, a turbocharger or its rotor assembly can require up to six balancing planes, which must be considered in the turbocharger design. This requires appropriate attention during the turbocharger design phase, affecting the areas of rotor dynamics, thermodynamics, wheel strength, and industrialization, to name just a few.

[0010] In the off-road commercial vehicle sector, as well as for applications in stationary turbomachines, power plant generators, or engines in the marine industry, turbochargers are balanced manually due to their size and mass, as well as the lower production volumes. For this purpose, compressor wheels have been developed, among others, which feature several threaded holes in the nose geometry arranged in a ring around the center. Depending on the magnitude of the imbalance, one or more counterweights of the same or different lengths or masses can be screwed into these holes.

[0011] In the geometric design of the wheels, for reasons of manufacturability, in addition to the areas for balance compensation - regardless of the type of unbalance compensation - surfaces for locking and options for torque transmission must be provided. Since the turbine and compressor wheels in turbochargers are connected to each other via the shaft, relative displacement or even rotational twisting relative to each other must be prevented under all circumstances in order to prevent both shaft torsion and changes in unbalance. This has led to compressor wheels being secured to the shaft either as a drilled version via a shaft nut or as a screwed version via the wheel itself. Furthermore, additional small parts, such as the bearing collar, Oil deflector ring and sealing bushing, fixed.

[0012] The geometries of the wheel noses must therefore usually fulfill at least one of these dual functions, which is not a problem as long as they are coordinated with each other or completed one after the other during production without causing any adverse effects. However, if it is intended to compensate for material or mass at the same plane or axial position on the wheel or running gear in a consecutive balancing process, this becomes significantly more difficult, as these can no longer be processed independently of each other.

[0013] The object of the present invention is therefore to provide a rotor and a balancing method with which one or more of the disadvantages known from the prior art can be partially or completely overcome. BRIEF DESCRIPTION OF THE INVENTION

[0014] To achieve the above-mentioned object, a rotor, a turbomachine, and a method for balancing a rotor assembly are provided according to the independent claims. Further aspects, advantages, and features of the present invention can be found in the dependent claims, the description, and the accompanying figures.

[0015] According to one aspect of the invention, a rotor for a turbomachine is provided. The rotor comprises a rotor base with an integrally designed balancing geometry for material removal for balancing. The balancing geometry has a first balancing section with a first center of mass and a second balancing section with a second center of mass. The first center of mass and the second center of mass are axially spaced from one another. A maximum radial extent of the first balancing section is less than a maximum radial Extension of the second balancing section. The first balancing section has a front-side, axial surface for axial material removal for balancing the rotor as a single part. The second balancing section has a front-side, axial surface for axial material removal for balancing a rotor assembly of a turbomachine with the rotor.

[0001] Thus, a rotor is advantageously provided which is improved in terms of balancing compared to the prior art. In particular, a rotor with a balancing geometry according to the embodiments described herein advantageously enables balancing of the rotor as an individual part and in the rotor assembly by means of material removal at the balancing geometry, so that balancing removal at the wheel disc or in the hub contour between the blades is no longer necessary. A further advantage of the rotor with a balancing geometry according to the embodiments described herein is that simple drilling tools and devices can be used which enable precise positioning and thus significantly reduce manual inaccuracies and the number of required iteration steps. Overall, this generates a cost advantage in turbocharger production and increases the quality of the imbalance compensation.

[0002] According to a second aspect of the invention, a rotor for a turbomachine is provided. The rotor comprises a rotor base with an integrally designed balancing geometry for material removal for balancing. The balancing geometry has an outer surface for a first material removal for balancing, in particular for balancing the rotor as a single part. Furthermore, the balancing geometry has an inner surface for a second material removal for balancing, in particular for balancing a rotor assembly of a turbomachine with the rotor. The outer surface has a greater radial distance from a rotational axis of the rotor than the inner surface.

[0003] According to a third aspect of the invention, a turbomachine, in particular a turbocharger, provided with a rotor according to one of the embodiments described herein.

[0004] According to a fourth aspect of the invention, a method for balancing a rotor assembly of a turbomachine having a rotor is provided. The method comprises measuring an imbalance of the rotor as an individual part. The rotor has a balancing geometry which is an integral part of a rotor base of the rotor. The balancing geometry has a first balancing section with a first center of mass. Furthermore, the balancing geometry has a second balancing section with a second center of mass. The first center of mass and the second center of mass are axially spaced from one another. A maximum radial extent of the first balancing section is less than a maximum radial extent of the second balancing section. Furthermore, the method comprises balancing the rotor as an individual part by first removing material at a first location of the first balancing section.Alternatively, the method may comprise balancing the rotor as an individual part by a first removal of material at a first location of the second balancing section. In addition, the method comprises assembling the rotor with the rotor balanced as an individual part. Furthermore, the method comprises measuring an imbalance of the rotor. In addition, the method comprises balancing the rotor by a second removal of material at a second location of the second balancing section, wherein the second location of the second balancing section is axially and / or radially spaced from the first location. Alternatively, the method may comprise balancing the rotor by a second removal of material at a second location of the first balancing section, wherein the second location of the first balancing section is axially and / or radially spaced from the first location of the second balancing section.

[0005] According to a fifth aspect of the invention, a method for balancing a rotor assembly of a turbomachine having a rotor is provided. The method comprises measuring an imbalance of the rotor as a single part. The rotor comprises a rotor base with an integrally designed balancing geometry for material removal for balancing. The balancing geometry has an outer surface for a first material removal for balancing the rotor as a single part. The balancing geometry also has an inner surface for a second material removal for balancing a rotor assembly of a turbomachine with the rotor. The outer surface is at a greater radial distance from a rotational axis of the rotor than the inner surface. In other words, the outer surface is typically a radially outer surface of the balancing geometry. The inner surface is typically a radially inner surface of the balancing geometry. The method also includes balancing the rotor as a single part by first removing material at a first location on the outer surface.Alternatively, the balancing of the rotor as an individual part can also be carried out by a first removal of material at a first location on the inner surface. In addition, the method comprises assembling the rotor with the rotor balanced as an individual part. Furthermore, the method comprises measuring an imbalance of the rotor. In addition, the method comprises balancing the rotor by a second removal of material at a second location on the inner surface, in particular wherein the second location is axially spaced from the first location. Alternatively, the balancing of the rotor can also be carried out by a second removal of material at a second location on the outer surface. BRIEF DESCRIPTION OF THE CHARACTERS

[0006] The invention will be explained below with reference to exemplary embodiments illustrated in figures, from which further advantages and modifications emerge. Herein: Figure 1 is a schematic sectional view of a rotor according to embodiments described herein; Figure 2 is a schematic perspective view of a balancing geometry according to embodiments described herein; Figures 3 and 4 are schematic perspective views of balancing geometries with exemplary material removals according to embodiments described herein; Figures 5A-5C show exemplary embodiments for axial material removal by means of designed drilling geometries; Figure 6 is a schematic perspective view of a balancing geometry with exemplary material removals according to another embodiment described herein; Figure 7 is a schematic sectional view of a rotor with an alternative balancing geometry according to embodiments described herein; Figure 8 is a schematic sectional view of a rotor assembly of a turbomachine according to embodiments described herein; and Figure 9 is a block diagram illustrating a method for balancing a turbocharger assembly having a rotor according to embodiments described herein. DETAILED DESCRIPTION OF THE FIGURES

[0007] Various embodiments are described below, one or more examples of which are shown in each figure. Each example is for illustrative purposes and is not to be understood as limiting. For example, features shown or described as part of one embodiment may be used on or in conjunction with any other embodiment to obtain a further embodiment. It is intended that the present disclosure include such including modifications and variations.

[0008] In the following description of the figures, the same reference numbers refer to the same or similar components. Generally, only the differences between the individual embodiments are described. Unless otherwise stated, the description of a part or aspect in one embodiment may also refer to a corresponding part or aspect in another embodiment.

[0009] With reference to Figures 1 to 7, a rotor 10 according to the present disclosure is described. For example, the rotor 10 may be a turbine wheel or a compressor wheel. According to one embodiment, which may be combined with other embodiments described herein, the rotor 10 comprises a rotor hub 11 with an integrally formed balancing geometry 12 for material removal for balancing. The balancing geometry 12 has a first balancing section 121 with a first center of mass S1 and a second balancing section 122 with a second center of mass S2. The first center of mass S1 and the second center of mass S2 are axially spaced from one another.

[0010] Thus, a rotor with an integrated balancing geometry is advantageously provided, which enables balancing as a single part on two planes as well as subsequent balancing on the rotor assembly to be carried out cost-effectively with high precision in balancing compensation using a manual or semi-automated process. For example, during single-part balancing, the first balancing section 121 and / or the second balancing section 122 can be used for material removal, and additionally, a balancing plane in the region of the rotor rear wall and / or an area at the rotor exit can be used for further material removal, so that single-part balancing typically takes place on two planes.

[0011] It should be noted that the first center of mass S1 and the second The center of mass S2 can also be spaced radially from one another, for example due to manufacturing tolerances. By way of example, Figure 1 shows the axial direction x, the radial direction r, and the axial distance Ax between the first center of mass S1 and the second center of mass S2. After balancing material has been removed from the first balancing section 121 and / or the second balancing section 122, the first center of mass S1 and the second center of mass S2 can be spaced axially and radially from one another.

[0012] In the present disclosure, a "balancing geometry" can be understood as a specific geometry of a rotor region, in particular the rotor nose, which allows the rotor to be balanced by removing material at specific points of the balancing geometry. It is therefore a geometry specifically designed for the purpose of balancing and is part of the rotor.

[0013] In the present disclosure, a "rotor nose" may be understood to mean the front portion of the rotor. In the context of a turbocharger rotor, such as a compressor wheel or turbine wheel, the rotor nose refers to the front portion of the rotor closest to the inlet or outlet region of the turbocharger.

[0014] In the present disclosure, a "balancing section" may be understood as an area of ​​the balancing geometry where material is removed to balance the rotor or a rotor assembly with the rotor. It is a specific part of the balancing geometry, designed according to the balancing requirements, where material is removed to ensure a uniform distribution of masses and correct rotation of the rotor or rotor assembly. The terms "first balancing section" and "second balancing section" may be understood as separate balancing sections. In other words, there is typically no overlap between the first balancing section and the second balancing section.

[0015] According to an embodiment which can be combined with other embodiments described herein, a maximum radial extension Ri max of the first balancing section 121 is less than a maximum radial extension R2max of the second balancing section 122.

[0016] According to one embodiment, which can be combined with other embodiments described herein, the first balancing section 121 has an end-face axial surface 121A for axial material removal for balancing. Alternatively or additionally, the first balancing section 121 can have a radial surface 121R for radial material removal for balancing.

[0017] In the present disclosure, an "axial surface" can be understood as a surface having a surface normal in a substantially axial direction. A "substantially axial direction" can be understood as a direction that can deviate from the exact axial direction within a tolerance range. For example, the substantially axial direction can be a direction that deviates from the exact axial direction x within a tolerance range of less than ± 40°, in particular less than ± 25°, and even more specifically less than ± 15°. A "radial surface" can be understood as a surface having a surface normal in a substantially radial direction. A "substantially radial direction" can be understood as a direction that can deviate from the exact radial direction within a tolerance range.For example, the substantially radial direction may be a direction that deviates from the exact radial direction x within a tolerance range of less than ± 40°, in particular less than ± 25°, and even more particularly less than ± 15°.

[0018] According to an embodiment that can be combined with other embodiments described herein, the second balancing section 122 has a frontal axial surface 122A for axial material removal for balancing. Alternatively or additionally, the second Balancing section 122 may have a radial surface 122R for radial material removal for balancing.

[0019] According to one embodiment, which can be combined with other embodiments described herein, the first balancing section 121 has an outer contour 1211 adapted for an assembly tool, as shown by way of example in Figure 2. Alternatively, the first balancing section 121 can have an inner contour 1212 adapted for an assembly tool, as shown by way of example in Figure 6.

[0020] According to one embodiment, which can be combined with other embodiments described herein, a rotor rear side 13 has a centrally arranged connecting element 14 for connection to a shaft 20, as shown by way of example in Figures 1 and 8. In particular, the centrally arranged connecting element 14 can be a blind hole with an internal thread, for example a three-start internal thread. Alternatively, the centrally arranged connecting element can be a socket, for example a socket with an external thread, in particular a three-start external thread. Alternatively, the connecting element 14 can be thread-free and can be connected to the shaft by means of a welded connection, in particular a friction-welded connection.

[0021] With reference to Figure 7, a rotor 10 with a further variant of the balancing geometry 20 is described. According to one embodiment, which can be combined with other embodiments described herein, the rotor 10 comprises a rotomase 11 with an integrally designed balancing geometry 12 for material removal for balancing. As shown by way of example in Figure 7, the balancing geometry 12 has an outer surface 123 for a first material removal for balancing. In addition, the balancing geometry 12 has an inner surface 124 for a second material removal for balancing. As shown in Figure 7, the outer surface 123 has a greater radial distance from a rotation axis 111 of the rotor 10 than the inner surface 124.

[0022] In the present disclosure, an "outer surface" may be understood as the outer surface of the balancing geometry. Specifically, the outer surface is the surface facing outward. An "inner surface" may be understood as an inward-facing surface of the balancing geometry. Typically, the inner surface of the balancing geometry is not visible from the outside in a side view, as it is located inside the balancing geometry.

[0023] As exemplified in Figure 7, the outer surface 123 of the balancing geometry 12 typically includes an outwardly directed axial surface 123A and an outwardly directed radial surface 123R. The inner surface 124 of the balancing geometry 12 typically includes an inwardly directed radial surface 124R and an axial surface 124A disposed in the interior of the balancing geometry.

[0024] It is understood that by using a rotor 10 according to one of the embodiments described herein in a turbomachine, for example in a turbocharger, an improved turbomachine, in particular an improved turbocharger, can be provided.

[0025] Accordingly, the turbomachine typically comprises a rotor with a balancing geometry 12 that has at least one material removal. In particular, the material removal may have occurred on one or more of the following surfaces: an end-side axial surface 121A of the first balancing section 121, a radial surface 121R of the first balancing section 121, a front axial surface 122A of the second balancing section 122, a radial surface 122R of the second balancing section 122, a radial surface 123R of an outer surface 123, an axial surface 123A of an outer surface 123, an axial surface 124A of an inner surface 124, and a radial surface 124R of an inner surface 124.

[0026] With reference to the block diagram in Figure 9, a A method 30 for balancing a rotor assembly of a turbomachine having a rotor 10 according to the present disclosure is described. Figure 8 shows a schematic sectional view of a rotor assembly of a turbocharger, wherein the rotor 10 is a compressor wheel connected to a turbine wheel 21 by means of a shaft 20.

[0027] According to an embodiment that can be combined with other embodiments described herein, the method 30 comprises measuring (schematically represented by block 31 in Figure 9) an imbalance of the rotor 10 as a single part. Furthermore, the method comprises balancing (schematically represented by block 32 in Figure 9) the rotor as a single part by first removing material at a first location of a balancing geometry, which is an integral part of a rotor base of the rotor. In addition, the method comprises assembling (schematically represented by block 33 in Figure 9) of the rotor assembly with the rotor balanced as a single part. Furthermore, the method includes measuring (schematically represented by block 34 in Figure 9) of an imbalance of the rotor. Furthermore, the method includes balancing (schematically represented by block 35 in Figure 9) the rotor by a second removal of material at a second location of the balancing geometry, wherein the second location is axially and / or radially spaced from the first location.

[0028] According to one embodiment that can be combined with other embodiments described herein, the rotor in method 30 is a rotor according to one of the embodiments described herein. The first location for removing material for balancing the rotor 10 as a single part can be located at the second balancing section 122, and the second location for removing material for balancing the rotor assembly can be located at the first balancing section 121. Alternatively, the first location for removing material for balancing the rotor 10 as a single part can be located at the first balancing section 121, and the second location for removing material for balancing the rotor assembly can be located at the second balancing section 122.

[0029] In connection with the alternative variant shown in Figure 7, it should be noted that the first location for removing material for balancing the rotor 10 as a single part can be located on the outer surface 123, and the second location for removing material for balancing the rotor assembly can be located on the inner surface 124. Alternatively, the first location for removing material for balancing the rotor 10 as a single part can be located on the inner surface 124, and the second location for removing material for balancing the rotor assembly can be located on the outer surface 123.

[0030] According to one embodiment, which can be combined with other embodiments described herein, the removal of material for balancing the rotor can take place as an individual part on a radial surface 122R and / or axial surface 122A of the second balancing section 122. The removal of material for balancing the rotor can take place on an end-side axial surface 121A and / or on a radial surface 121R of the first balancing section 121. Alternatively, the removal of material for balancing the rotor can take place as an individual part on an end-side axial surface 121A and / or on a radial surface 121R of the first balancing section 121. Likewise, alternatively, the removal of material for balancing the rotor can take place on a radial surface 122R and / or axial surface 122A of the second balancing section 122.

[0031] In connection with the alternative variant shown in Figure 7, it should be noted that the removal of material for balancing the rotor can be carried out as an individual part on the radial surface 123R and / or the axial surface 123A of the outer surface 123. The removal of material for balancing the rotor can be carried out on an axial surface 124A and / or on a radial surface 124R of the inner surface 124. Alternatively, the removal of material for balancing the rotor can be carried out as an individual part on the radial surface 124R and / or the axial surface 124A of the inner surface 124. Likewise, Alternatively, material may be removed for balancing the rotor on the radial surface 123R and / or the axial surface 123A of the outer surface 123.

[0032] The removal of material on the frontal axial surface 121A and / or the radial surface 121R of the first balancing section 121 can be carried out by implementing at least one drilling geometry 15. Likewise, the removal of material on a radial surface 122R and / or axial surface 122A of the second balancing section 122 can be carried out by implementing at least one drilling geometry. As an example, a drilling geometry 15 in the frontal axial surface 121A is shown in Figure 3. Figure 4 shows an example with a first drilling geometry 151 and a second drilling geometry, which were each implemented in the frontal axial surface 121A. Furthermore, radial material removal means 16 are shown as examples in Figures 3, 4 and 6. The removal of material can be carried out, for example, by drilling, milling or other mechanical material removal methods.

[0033] In connection with the alternative variant shown in Figure 7, it should be noted that the removal of material on the axial surface 123A and / or the radial surface 123R of the outer surface 123 can be carried out by implementing at least one drilling geometry 15. Likewise, the removal of material on a radial surface 124R and / or axial surface 124A of the inner surface 124 can be carried out by implementing at least one drilling geometry. It should also be noted that the removal of material on the axial surface 123A and / or the radial surface 123R of the outer surface 123 can be carried out by milling. Likewise, the removal of material on a radial surface 124R and / or axial surface 124A of the inner surface 124 can be carried out by milling.

[0034] The drilling geometry can, for example, be cylindrical (not explicitly shown) or conical (see Figure 5A). Furthermore, the drilling geometry can be designed with a cylindrical (see Figure 5C) or conical counterbore (see Figure 5B). It is understood that the drilling geometry can also have other contours and.

[0035] As can be seen from the embodiments described herein, the invention advantageously provides a rotor and a balancing method that are improved over the prior art. By using a rotor with a balancing geometry according to the described embodiments, the rotor can be balanced more effectively, both as an individual part and in the overall rotor assembly, by removing material from the balancing geometry. This eliminates the need for balancing removal on the wheel disc or in the hub contour between the blades. A further advantage of this balancing geometry is that simple drilling tools and devices can be used to enable precise infeed. Furthermore, balancing drilling geometries can be conical, which reduces the risk of unwanted material accumulation and, if necessary, facilitates repeated balancing removal at the same or adjacent location.This significantly reduces manual inaccuracies and the number of required iteration steps, resulting in cost savings in turbocharger manufacturing and improving the quality of unbalance compensation. LIST OF REFERENCE SYMBOLS 10 Rotor 11 Rotor nose 111 Rotation axis 112 shovel 12 Balancing geometry 121 first balancing section 121 A front axial surface of the first balancing section for axial Material removal 121R radial surface of the first balancing section for radial Material removal 1211 for assembly tool adapted outer contour of the first Balancing geometry 1212 for assembly tool adapted inner contour of the first balancing section 122 second balancing section 122 A frontal axial surface 122R radial surface of the second balancing section for radial Material removal 123 outer surface of the balancing geometry 123A axial surface of the outer surface 123R radial surface of the outer surface 124 internal surface of the balancing geometry 124 A axial surface of the inner surface 124R radial surface of the inner surface 13 Rotor back 14 Connecting element 15 Drilling geometry 151 first drilling geometry 152 second drilling geometry 16 radial material removal 0 shaft 1 turbine wheel first center of mass second center of mass Method for balancing a rotor with a rotor-35 blocks of the block diagram to illustrate the process steps of the balancing process

Claims

CLAIMS 1. Rotor (10) for a turbomachine, comprising a rotor nose (11) with an integrally designed balancing geometry (12) for material removal for balancing, wherein the balancing geometry (12) has a first balancing section (121) with a first center of mass (S1) and a second balancing section (122) with a second center of mass (S2), wherein the first center of mass (S1) and the second center of mass (S2) are axially spaced from one another, wherein a maximum radial extension (Ri max ) of the first balancing section (121) is less than a maximum radial extension (R 2max) of the second balancing section (122), wherein the first balancing section (121) has an end-side axial surface (121A) for axial material removal for balancing the rotor (10) as a single part, and wherein the second balancing section (122) has an end-side axial surface (122A) for axial material removal for balancing a rotor of a turbomachine with the rotor (10).

2. Rotor (10) according to claim 1, wherein the first balancing section (121) further comprises a radial surface (121R) for radial material removal for balancing.

3. Rotor (10) according to claim 1 or 2, wherein the second balancing section (122) further comprises a radial surface (122R) for radial material removal for balancing.

4. Rotor (10) according to one of claims 1 to 3, wherein the first balancing section (121) has an outer contour (1211) or inner contour (1212) adapted for an assembly tool.

5. Rotor (10) according to claims 1 to 4, wherein a rotor rear side (13) has a centrally arranged connecting element (14) for connection to a shaft (20), in particular wherein the centrally arranged connecting element (14) is a blind hole with an internal thread, in particular a three-start thread, or in particular wherein the centrally arranged connecting element is a nozzle, in particular with an external thread.

6. Rotor according to one of claims 1 to 5, wherein the rotor is a compressor wheel or a turbine wheel.

7. Rotor (10) for a turbomachine, comprising a rotor nose (11) with an integrally designed balancing geometry (12) for a material removal for balancing, wherein the balancing geometry (12) has an outer surface (123) for a first material removal for balancing, and wherein the balancing geometry (12) has an inner surface (124) for a second material removal for balancing, wherein the outer surface (123) has a greater radial distance from a rotation axis (111) of the rotor than the inner surface (124).

8. Turbomachine, in particular turbocharger, with a rotor (10) according to one of claims 1 to 7.

9. Turbomachine according to claim 8, wherein the balancing geometry (12) comprises at least one material removal on one or more surfaces selected from the group consisting of an end-side axial surface (121A) of the first balancing section (121), a radial surface (121R) of the first balancing section (121), an end-side axial surface (122A) of the second balancing section (122), a radial surface (122R) of the second balancing section (122), a radial surface (123R) of an outer surface (123), an axial surface (123A) of an outer surface (123), an axial surface (124A) of an inner surface (124), and a radial surface (124R) of an inner surface (124).

10. A method (30) for balancing a rotor assembly of a turbomachine having a rotor (10), comprising: - measuring (31) an unbalance of the rotor (10) as a single part, wherein the rotor has a balancing geometry (12) which is an integral part of a rotor nose (11) of the rotor (10), wherein the balancing geometry (12) has a first balancing section (121) with a first center of mass (S1) and a second balancing section (122) with a second center of mass (S2), wherein the first center of mass (S1) and the second center of mass (S2) are axially spaced from one another, wherein a maximum radial extension (Ri max ) of the first balancing section (121) is less than a maximum radial extension (R2max) of the second balancing section (122), - Balancing (32) the rotor (10) as a single part by a first removal of material at a first location of the first balancing section (121), - assembling (33) the rotor with the rotor (10) balanced as a single part; - measuring (34) an imbalance of the rotor, and - Balancing (35) the rotor by a second removal of material at a second location of the second balancing section (122), wherein the second location is axially and / or radially spaced from the first location.

11. The method (30) according to claim 10, wherein the rotor (10) is a rotor according to one of claims 1 to 6, wherein the first location for removing material for balancing the rotor (10) as a single part is located at the second balancing section (122), and wherein the second location for removing material for balancing the rotor assembly is located at the first balancing section (121), or vice versa.

12. The method (30) according to claim 11, wherein the removal of material for balancing the rotor (10) as a single part on a radial surface (122R) and / or axial surface (122A) of the second balancing section (122), and wherein the removal of material for balancing the rotor takes place on an end-side axial surface (121A) and / or on a radial surface (121R) of the first balancing section (121), or vice versa.

13. The method (30) according to claim 12, wherein the removal of material on the frontal axial surface (121A) and / or a radial surface (121R) of the first balancing section (121) is carried out by executing at least one drilling geometry (15).

14. The method according to claim 13, wherein the at least one drilling geometry (15) is cylindrical or conical, and in particular wherein the at least one drilling geometry is designed with a cylindrical or conical countersink.

15. A method (30) for balancing a rotor assembly of a turbomachine having a rotor (10), comprising: - Measuring an unbalance of the rotor (10) as a single part, wherein the rotor (10) comprises a rotor nose with an integrally designed balancing geometry for a material removal for balancing, wherein the balancing geometry has an outer surface for a first material removal for balancing the rotor as a single part, wherein the balancing geometry further has an inner surface for a second material removal for balancing a rotor assembly of a turbomachine with the rotor, wherein the outer surface has a greater radial distance from a rotational axis of the rotor than the inner surface, - Balancing the rotor as a single part by first removing material at a first point on the outer surface, - Assembling the rotor assembly with the rotor balanced as a single part, - Measuring an imbalance of the rotor, and - Balancing the rotor by a second removal of material at a second location of the inner surface, in particular wherein the second location is axially spaced from the first location, and in particular wherein the rotor is a rotor according to claim 7.

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