Damping assembly for damping torsional vibrations of shaft, turbomachine comprising damping assembly and method of damping torsional vibrations of shaft

Abstract

A damping assembly (10) for damping torsional vibrations of a shaft (11), in particular of a main shaft of a turbomachine (20), is described. The damping assembly (10) includes a one-piece bushing (12) disposed about the shaft (11). The unitary bushing (12) has an aspect ratio L / Dout > = 2, where L is an axial length of the unitary bushing (12) and Dout is an outer diameter of the unitary bushing (12). Further, the damping assembly (10) comprises an axial clamping portion (14) of the unitary bushing (12), a first peripheral press-fit portion (131) between a first end portion (121) of the unitary bushing (12) and the shaft (11), and a second peripheral press-fit portion (132) between a second end portion (122) of the unitary bushing (12) and the shaft (11). A radial gap (13) between the integral bushing (12) and the shaft (11) is provided between the first peripheral press-fit portion (131) and the second peripheral press-fit portion (132).

Description

Technical Field

[0001] Embodiments of this disclosure relate to damping assemblies and methods for suppressing torsional vibrations of shafts, particularly the main shaft of a turbine. Other embodiments of this disclosure relate to turbines including damping assemblies according to embodiments of this disclosure. Background Technology

[0002] Turbochargers are used to increase the power of reciprocating engines. They have a high-speed rotor unit that includes a turbine, a compressor, and a shaft connecting the turbine and compressor. In an exhaust gas turbocharger, the turbine is driven by the exhaust gases from the internal combustion engine. The turbine drives the compressor via a common shaft. The gas compressed by the compressor is sent into the combustion chamber to boost the engine. The pressure of the exhaust gases from the internal combustion engine driving the turbine is not constant, thus the turbocharger shaft is excited and vibrates. Furthermore, pressure pulsations depend on the opening and closing characteristics of the engine's exhaust valves and the exhaust line design. The spectrum of these pressure pulsations is clearly dominated by the engine's ignition frequency, which depends on the number of cylinders, the operating mode (two-stroke / four-stroke), and the engine speed. When designing mechanical systems or structures, the interaction between torsional excitation and resonant natural frequencies should be carefully considered and managed to ensure the system's safety, reliability, and lifespan. Special attention to material properties, geometry, damping, and monitoring helps mitigate the risks associated with torsional vibrations near the resonant frequencies.

[0003] Modern four-stroke engines typically employ pulse boosting to achieve good partial load and responsiveness. These pulse boosting systems generate strong, high-frequency pressure fluctuations in the exhaust pipe. Depending on the engine load or speed, this excites the rotor's natural torsional frequency. Because turbocharger rotors are typically very rigid and have low torsional damping, unacceptably high torque amplitudes can occur at resonance. This can place excessive stress on the turbocharger shaft joints, potentially leading to torsional fracture in extreme cases.

[0004] Furthermore, research and measurements indicate that, in addition to the engine's order frequencies, higher harmonics of those frequencies also exist in the pressure pulsation spectrum. These higher-order pressure pulsations coincide with the torsional natural frequencies of the turbocharger shaft. These unavoidable resonant oscillations at variable engine speeds also contribute to torsional stress in the turbocharger shaft. Steeper camshaft camshaft protrusions and increased pressure ratios in the engine and turbocharger can lead to stronger excitation, resulting in greater torsional stress in the turbocharger shaft. The increased power density required for the turbocharger shaft exacerbates this problem.

[0005] A well-known method to reduce the load caused by torsional vibration in a turbine is to select a larger shaft diameter to increase shaft stiffness. This increases the torsional natural frequency and reduces the vibration amplitude. However, the vibration characteristics are still not suppressed, and power losses in the turbocharger shaft bearings increase.

[0006] Known torsional vibration dampers for relatively slowly rotating crankshafts include, for example, oil-driven dampers, rubber dampers, viscous torsional vibration dampers, or silicone oil-rubber dampers. These dampers typically have a flywheel mass mechanically coupled to the crankshaft via a damping mechanism. The flywheel mass damper is mounted at the end of the crankshaft because this is where the largest torsional vibration amplitude occurs.

[0007] Therefore, in view of the above, there is a need for improved damping components and methods for suppressing torsional vibrations of shafts, particularly turbine main shafts, which at least partially overcome some of the problems of the prior art. Summary of the Invention

[0008] In view of the foregoing, a damping assembly for suppressing torsional vibration of a shaft and a method for suppressing torsional vibration of a shaft are provided according to the independent claims. Other aspects, advantages, and features will be apparent from the dependent claims, the description, and the drawings.

[0009] According to one aspect of this disclosure, a damping assembly is provided for suppressing torsional vibrations of a shaft, particularly a turbine main shaft. The damping assembly includes an integral bushing disposed around the shaft. The integral bushing has an aspect ratio L / D. out ≥2, where L is the axial length of the integral bushing, and D out This refers to the outer diameter of the integral bushing. Furthermore, the damping assembly includes an axial clamping portion of the integral bushing, a first peripheral press-fit portion between the first end portion of the integral bushing and the shaft, and a second peripheral press-fit portion between the second end portion of the integral bushing and the shaft. A radial clearance between the integral bushing and the shaft is provided between the first peripheral press-fit portion and the second peripheral press-fit portion.

[0010] Therefore, the damping assembly of this disclosure is an improvement over conventional damping assemblies used to suppress torsional vibrations of shafts, particularly in terms of simplicity, cost-effectiveness, damping quality, and operating characteristics. In particular, embodiments of the damping assembly described herein advantageously improve the reliability, performance, and lifespan of machinery using this damping assembly by reducing the negative effects of torsional vibrations, such as fatigue, wear, and potential structural damage.

[0011] According to another aspect of this disclosure, a turbine is provided that includes a damping assembly for suppressing torsional vibrations of a shaft according to any embodiment described herein. In particular, the turbine may be a turbocharger. For example, the shaft may connect a compressor impeller of a compressor to a turbine impeller of a turbine.

[0012] According to another aspect of this disclosure, a method for suppressing torsional vibration of a shaft, particularly the main shaft of a turbine, is provided. The method includes suppressing torsional vibration through friction, particularly micro-friction, between integral bushings disposed around the shaft. The integral bushings have an aspect ratio L / D. out ≥ 2, where L is the axial length of the integral bushing, and D out It is the outer diameter of the integral bushing. Friction is provided at the interface of the axial clamping portion of the integral bushing, at the interface between the first end portion of the integral bushing and the shaft at the first peripheral press-fit portion, and at the interface between the second end portion of the integral bushing and the shaft at the second peripheral press-fit portion. A radial clearance between the integral bushing and the shaft is provided between the first peripheral press-fit portion and the second peripheral press-fit portion. Attached Figure Description

[0013] To gain a more concrete understanding of the features of this disclosure as set forth above, reference can be made to the embodiments for a more detailed description of the invention briefly described above. The accompanying drawings relate to embodiments of this disclosure and are described below:

[0014] Figures 1 to 4 A schematic diagram of a damping assembly for suppressing torsional vibrations of a shaft, according to exemplary embodiments described herein, is shown; and

[0015] Figure 5 A flowchart illustrating a method for suppressing torsional vibration of a shaft according to embodiments described herein is shown. Detailed Implementation

[0016] Reference will now be made in detail to various embodiments, one or more examples of which are illustrated in the various accompanying drawings. Each example is provided by way of explanation and is not intended to be limiting. For example, features illustrated or described as part of one embodiment may be used in or in combination with any other embodiment to produce yet another embodiment. This disclosure is intended to include such modifications and variations.

[0017] In the following description of the accompanying drawings, the same reference numerals refer to the same or similar parts. Generally, only the differences between the various embodiments are described. Unless otherwise stated, the description of a part or aspect of one embodiment also applies to a corresponding part or aspect of another embodiment.

[0018] Example reference Figures 1 to 4The present disclosure describes a damping assembly 10 for suppressing torsional vibrations of shaft 11 according to an embodiment of the present disclosure.

[0019] According to an embodiment that can be combined with other embodiments described herein, the damping assembly 10 includes an integral bushing 12 disposed around a shaft 11. The integral bushing 12 has an aspect ratio L / D. out ≥ 2, where L is the axial length of the integral bushing 12, and D out This refers to the outer diameter of the integral bushing 12. The "axial length L" of the integral bushing refers to the distance measured along the bushing's axis, which typically corresponds to the length of the bushing in a direction parallel to the shaft it encloses. In other words, it is a linear measurement of the bushing along its central axis from one end to the other. The "outer diameter" of the integral bushing refers to the total distance measured through the bushing, from one outer edge through the bushing's central axis to the opposite outer edge.

[0020] According to embodiments that can be combined with other embodiments described herein, the aspect ratio L / D out It can be L / D out ≥ 3, especially L / D out ≥ 4, especially L / D out ≥ 5. For example Figures 1 to 3 As shown, the outer diameter D out It is generally constant at least at the first end portion 121 and / or the second end portion 122 of the bushing 12. Figure 1 An example is shown where the outer diameter D out It is constant over the entire length L of the bushing. Figure 2 An example is shown where the outer diameter D out The axial clamping portion 141 is constant from the diameter-increasing bushing portion 125, and particularly up to the first end shoulder 127. Furthermore, Figure 2 Show the outer diameter D out The distance from the second axial clamping portion 141 to the diameter-increasing bushing portion 125 can be constant, especially up to the second end shoulder 128.

[0021] Furthermore, the damping assembly 10 includes an axial clamping portion 14 of the integral bushing 12, a first peripheral press-fit portion 131 between the first end portion 121 of the integral bushing 12 and the shaft 11, and a second peripheral press-fit portion 132 between the second end portion 122 of the bushing 12 and the shaft 11. A radial clearance 13 between the integral bushing 12 and the shaft 11 is provided between the first peripheral press-fit portion 131 and the second peripheral press-fit portion 132.

[0022] Therefore, the damping assembly according to embodiments of this disclosure is an improvement over conventional damping methods for suppressing torsional vibrations of shafts. In particular, embodiments of the damping assembly described herein advantageously provide a simple and cost-effective damping assembly with high torsional damping capability against shaft excitations (e.g., excitations caused by a motor and / or at the shaft ends (i.e., rotor positions, such as compressor or turbine positions), as further described below. Thus, the embodiments described herein advantageously provide smooth operating characteristics, minimizing the risk of rotor failure.

[0023] In this disclosure, a "damping assembly for suppressing torsional vibration of a shaft" can be understood as a mechanical system configured to reduce or control unwanted oscillations and vibrations occurring along the length of a rotating shaft, particularly harmful oscillations and vibrations involving bending or torsional motion. Torsional vibration can be understood as oscillations or vibrations that occur when a shaft rotates. Torsional vibration typically involves bending or twisting motions along the length of the shaft. Such vibrations can be harmful, leading to mechanical failure, performance degradation, and noise.

[0024] In this disclosure, "sleeve" can be understood as a cylindrical or tubular element configured to be assembled around a shaft. A one-piece sleeve refers to a single, continuous sleeve. In other words, the term "one-piece" emphasizes that the sleeve is constructed as a single, integral unit without seams or joints. It should be understood that the term "sleeve" as used in this disclosure refers to a one-piece sleeve.

[0025] In this disclosure, "axial clamping portion of the bushing" can be understood as a mechanism involving applying clamping force or pressure in the axial direction along the length of the bushing. In particular, it should be understood that the axial clamping portion fixes or secures the bushing in place along the axis of the shaft. Furthermore, it should be understood that the axial clamping portion typically has a clamping interface at each axial end of the bushing.

[0026] In this disclosure, a "peripheral press fit" can be understood as a specific type of mechanical fastening or assembly method for connecting two components (typically cylindrical or tubular in shape). In a peripheral press fit, one component is inserted into another, and the fit is achieved primarily by applying pressure around the periphery or circumference of the component rather than along its axial length. In other words, a "peripheral press fit" can be understood as the connection of two components (particularly those with a cylindrical or tubular shape), where one component is inserted into the other with a secure and tight fit. This connection relies on an interference fit between the outer periphery or circumference of the inserted component and the inner periphery or circumference of the receiving component. In a peripheral press fit, an interference fit is intentionally created where the dimensions of the inner and outer diameters of the components prevent them from being easily assembled together. This interference fit provides the necessary friction between the components.

[0027] In this disclosure, "radial clearance between the bushing and the shaft" can be understood as the space or gap between the inner surface of the bushing and the outer surface of the shaft, wherein the bushing does not directly contact the shaft. The term "radial" refers to a direction extending outward from the central axis of the shaft in a radial direction. The central axis 110 of the shaft, the radial direction r, and the axial direction x are... Figures 1 to 4 As shown in the image.

[0028] According to an embodiment that can be combined with other embodiments described herein, the axial clamping portion 14 is provided by a first axial pressing portion 141 at a first axial end 123 of the bushing 12 and a second axial pressing portion 142 at a second axial end 124 of the bushing 12. In other words, the axial clamping portion 14 is provided by axial pressing portions provided at both ends of the bushing.

[0029] According to embodiments that can be combined with other embodiments described herein, an aspect ratio L greater than or equal to 0.6 is set. p1 / D p1 L p1 It is the axial distance between the first peripheral press-fit part 131 and the first axial pressing part 141, and wherein D p1 It is the inner diameter of the integral bushing 12 at the first peripheral press-fit portion 131, such as Figures 1 to 3 As shown in the example. In other words, the aspect ratio L p1 / D p1 It can be L p1 / D p1 ≥ 0.6, especially L p1 / D p1 ≥ 0.7. Alternatively, an aspect ratio L greater than or equal to 0.6 may be provided. p2 / D p2 L p2 It is the axial distance between the second peripheral press-fit part 132 and the second axial pressing part 142, D p2 It is the inner diameter of the integral bushing 12 at the second peripheral press-fit portion 132. In other words, the aspect ratio L p2 / D p2 It can be L p2 / D p2 ≥ 0.6, especially L p2 / D p2 ≥ 0.7.

[0030] According to embodiments that can be combined with other embodiments described herein, a radial clearance 135 may be provided between the first axial end 123 of the bushing 12 and the shaft 11. Additionally or alternatively, a radial clearance 136 may be provided between the second axial end 124 of the bushing 12 and the shaft 11.

[0031] According to an embodiment that can be combined with other embodiments described herein, the shaft 11 includes a shoulder 111 for providing a stop for the axial clamping portion 14 of the bushing 12. In particular, the shoulder 111 may be provided on the turbine side of the turbine's main shaft, especially when the turbine is a turbocharger.

[0032] A "shoulder" can be understood as a design feature or component on a shaft that serves as a stop. Typically, a shoulder is provided by a widened or thickened section of the shaft. The function of the shoulder is to act as a stop for the axial clamping portion 14 of the bushing 12. In other words, the axial clamping portion typically presses against or abuts against the shoulder directly or indirectly (i.e., via an intermediate element, such as the ring element described below), thereby preventing further axial movement of the bushing and thus axially clamping the bushing.

[0033] According to embodiments that can be combined with other embodiments described herein, ring element 15, particularly a thrust ring, is disposed between shoulder 111 and bushing 12. Typically, ring element 15 is disposed between shoulder 111 and second axial end 124 of bushing 12. Alternatively (not explicitly shown in the figures), ring element 15 may be disposed around shaft 11 on first axial end 123 of bushing 12. For example, ring element 15 on first axial end 123 may be disposed between bushing 12 and radial disc 19 (particularly sealing disc), as described in this disclosure. Furthermore, it should be understood that one or more ring elements, particularly one or more thrust rings, may be disposed around shaft 11 on first axial end 123 and / or second axial end 124 of bushing 12. Typically, one or more ring elements are individual elements. According to embodiments that can be combined with other embodiments described herein, at least one of the one or more ring elements may be part of bushing 12.

[0034] According to embodiments that can be combined with other embodiments described herein, the axial clamping portion 14 is provided by a preload applied through the threaded connection portion 16. In particular, this preload may be provided solely by the threaded connection portion described in this disclosure. For example, the threaded connection portion 16 providing the preload may be the threaded connection between the rotor 17 and the shaft 11. Alternatively, the threaded connection portion 16 providing the preload may be the threaded connection between the nut 18 and the shaft 11. In particular, the nut 18 is used to axially secure the rotor to the shaft 11. The rotor 17, secured to the shaft 11 via the threaded connection portion 16, may be a compressor impeller 211. Although not explicitly shown in the figures, it should be understood that, alternatively, the rotor secured to the shaft 11 via the threaded connection portion 16 may be a turbine impeller.

[0035] In this disclosure, as described herein, "preload applied through the threaded connection" can be understood as applying a controlled force or tension by tightening the threaded connection to provide axial clamping of the bushing. In other words, the preload can be achieved by applying force through the threaded connection to produce an axial clamping effect, particularly with a predefined force or tension.

[0036] According to embodiments that can be combined with other embodiments described herein, the damping assembly 10 further includes a radial disk 19 disposed at a first axial end 123 of the bushing 12. In particular, the radial disk may be disposed between the rotor 17 described herein and the first axial end 123 of the bushing 12. For example, the radial disk 19 may be a sealing disk. A “sealing disk” can be understood as a disk specifically configured to provide a seal or barrier between two adjacent components (e.g., the rotor and bushing described herein), particularly preventing leakage or entry into or exit of fluids (such as lubricants or contaminants) from the damping assembly.

[0037] According to embodiments that can be combined with other embodiments described herein, the damping assembly 10 further includes a third peripheral press-fit portion 133 between the bushing 12 and the shaft 11. For example, the third peripheral press-fit portion 133 may be disposed at the first end portion 121. Additionally or alternatively, the damping assembly 10 may also include a fourth peripheral press-fit portion 134 between the bushing 12 and the shaft 11. The fourth peripheral press-fit portion 134 may be disposed at the second end portion 122. Typically, the third peripheral press-fit portion 133 is disposed close to or adjacent to the first peripheral press-fit portion 131. Depending on the axial position of the first peripheral press-fit portion 131, the third peripheral press-fit portion 133 may be disposed closer to or further away from the first axial end portion 123 than the first peripheral press-fit portion 131. Typically, the fourth peripheral press-fit portion 134 is disposed close to or adjacent to the second peripheral press-fit portion 132. Depending on the axial position of the second peripheral press-fit portion 132, the fourth peripheral press-fit portion 134 can be positioned closer to the second axial end 124 than the second peripheral press-fit portion 132, or further away from the second axial end 124 than the second peripheral press-fit portion 132. Furthermore, it should be understood that, according to embodiments that can be combined with other embodiments described herein, only one of the third peripheral press-fit portion 133 and the fourth peripheral press-fit portion 134 may be provided, for example, in the region of the diameter-increasing bushing portion 125 described below.

[0038] According to an embodiment that can be combined with other embodiments described herein, the bushing 12 has an enlarging bushing portion 125 having a maximum diameter D. max and axial length l, where the ratio D max / l is 0.54 ≤ D max / l ≤ 2.8. Additional or alternative land, ratio D max / L is 0.24 ≤ D max / L ≤ 0.38, where L is the total axial length of bushing 12. See, for example, [reference needed]. Figure 2 It should be understood that D max This can be the diameter of one or more end shoulders of the diameter-enlarging bushing portion 125, particularly the first end shoulder 127 and / or the second end shoulder 128. In the absence of end shoulders, it should be understood that D... max This refers to the diameter of the diameter-enlarging bushing portion 125. Therefore, it should be understood that the diameter-enlarging bushing portion 125 may include a first end shoulder 127 at a first end of the diameter-enlarging bushing portion 125. Additionally or alternatively, the diameter-enlarging bushing portion 125 may include a second end shoulder 128 at a second end of the diameter-enlarging bushing portion 125. See exemplary reference... Figure 2 It should be understood that the first end and the second end of the diameter-increasing bushing portion 125 are axially opposite ends.

[0039] According to embodiments that can be combined with other embodiments described herein, the bushing 12 has a radially outer base 126 for one or more magnets 231 of the motor 23. In particular, the motor 23 is a permanent magnet motor, especially a permanent magnet synchronous motor. For example, the radially outer base 126 may be disposed at the diameter-enlarging bushing portion 125 described herein. The diameter-enlarging bushing portion 125 may have a first diameter D1 and a second diameter D2, wherein the first diameter D1 is larger than the second diameter D2, such as... Figure 2 As shown in the example.

[0040] "Base for one or more magnets" can be understood as a specific feature or component of the bushing configured to position or accommodate one or more magnets. In other words, the radially outer base for one or more magnets on the bushing serves as a location or space on the outer surface of the bushing for placing one or more magnets.

[0041] A "permanent magnet motor" refers to a motor, such as an electric motor or generator, that relies on permanent magnets rather than excitation windings powered by an external power source to generate its magnetic field. These machines are also called permanent magnet motors. In a permanent magnet motor, the magnetic field required for its operation is generated by permanent magnets. These magnets are typically made of materials such as neodymium, samarium cobalt, or ferrite. They maintain their magnetism without the need for an external power source. Permanent magnet motors are known for their simplicity and high efficiency. They eliminate the need for excitation windings and the associated power consumption required to generate the magnetic field, thus making them more energy efficient. Furthermore, permanent magnet motors are advantageous because they can be more compact and lighter compared to motors with excitation windings. Additionally, the output of permanent magnet motors can be precisely controlled, making them ideal for applications that emphasize speed and torque control. Moreover, permanent magnet motors can be used for regenerative braking. They can act as generators during braking or deceleration, converting kinetic energy back into electrical energy, which helps improve overall efficiency.

[0042] Exemplary reference Figure 4 It should be understood that, according to another aspect of this disclosure, a turbine 20 is provided, which includes a damping assembly 10 for suppressing torsional vibrations of the shaft 11 according to any embodiment described herein. In particular, the turbine 20 may be a turbocharger. For example, the shaft may connect the compressor impeller 211 of the compressor 21 to the turbine impeller 221 of the turbine 22.

[0043] According to embodiments that can be combined with other embodiments described herein, the turbine 20 also includes a motor 23. Therefore, the turbine 20 can be an electric turbocharger, an electric compressor, or an electric turbine. In particular, the motor 23 can be a permanent magnet motor. For example, the motor 23 can be disposed between the compressor impeller 211 and the turbine impeller 221. More specifically, the motor 23 typically includes one or more magnets 231 mounted on a radially outer base 126 of the bushing 12. It should be understood that the one or more magnets 231 mounted on the radially outer base 126 of the bushing 12 can also be referred to as the rotor magnets of the motor. Furthermore, as... Figure 4 As exemplarily shown, one or more stator magnets 232 are typically provided surrounding one or more rotor magnets 231 of the motor. One or more magnets 231 mounted on the radially outer base 126 may be held by sleeves (particularly carbon fiber sleeves) arranged around one or more magnets 231. According to one example, one or more magnets 231 may be arranged between balance plates 24 mounted on a bushing. The balance plates may be part of the bushing 12.

[0044] Reference Figure 5 The flowchart describes an embodiment of the method 30 for suppressing torsional vibration of shaft 11 according to the present disclosure.

[0045] According to embodiments that can be combined with other embodiments described herein, method 30 includes suppressing (by) friction, particularly micro-friction, between bushings 12 disposed around shaft 11. Figure 5 (Box 31 in the figure indicates) torsional vibration. Friction is provided at the interface of the axial clamping portion 14 of the bushing 12, at the interface of the first end portion 121 of the bushing 12 and the shaft 11 at the first peripheral press-fit portion 131, and at the interface of the second end portion 122 of the bushing 12 and the shaft 11 at the second peripheral press-fit portion 132. Typically, the method also includes using (by...) Figure 5 (Box 32 in the document indicates) the damping component 10 according to any embodiment described herein.

[0046] It should be understood that in this disclosure, the terms "friction" and "micro-friction" refer to mechanisms used to suppress or reduce torsional vibrations.

[0047] Friction is a force that resists relative motion or the tendency to move between two contacting surfaces. It acts tangentially on the surfaces and is caused by the interaction of surface molecules. It can manifest as resistance to sliding, rolling, or any other motion between the surfaces. In the context of suppressing torsional vibrations, friction is used as a means of absorbing or dissipating some of the mechanical energy generated by these vibrations. By generating resistance in a system, friction helps reduce oscillations and stabilize motion.

[0048] Microfriction is a specific type of friction that operates at a very small scale, typically involving very small forces and minute surface interactions. It is generally used to describe frictional properties at the microscopic or nanoscale. In the context of the methods described herein, "microfriction" is used to indicate that friction used to suppress torsional vibrations is at a tiny or microscale level. This may involve using special materials, coatings, or surface treatments to generate extremely low levels of friction, which can effectively reduce vibrations without causing significant wear on the component.

[0049] In view of the embodiments described herein, it should be understood that an improved damping assembly and an improved method for suppressing torsional vibrations of shafts, particularly the main shaft of turbines, are provided compared to the prior art. In particular, embodiments of this disclosure advantageously provide a simple and cost-effective damping method with high torsional damping capability against shaft excitations (e.g., excitations induced at the motor and / or at the shaft ends (i.e., rotor positions, such as compressor or turbine positions)). Therefore, the embodiments described herein advantageously provide smooth operating characteristics, minimizing the risk of rotor failure.

[0050] Furthermore, it should be noted that the embodiments of this disclosure are particularly applicable to the shafts of large-frame turbochargers, i.e., shafts with a diameter greater than 150 mm. Large-frame turbochargers typically have shafts welded to the turbine head, thus forming an inseparable connection with the shaft. Therefore, the assembly of the entire machine is limited, or in other words, predetermined to some extent. Moreover, unlike the automotive industry, due to the high lifespan requirements (approximately 80,000 hours) in the power generation and marine sectors, such turbochargers rely on the likelihood of repeated maintenance and inspection.

[0051] Although the foregoing describes an embodiment, other and further embodiments may be devised without departing from the basic scope, which is defined by the appended claims.

[0052] List of reference numerals

[0053] 10 Damping components

[0054] 11-axis

[0055] 110 axis centerline

[0056] 111 Shaft shoulder

[0057] 12 Integrated bushings

[0058] 121 First end portion of the bushing

[0059] The second end portion of the 122 bushing

[0060] 123 First Axial End

[0061] 124 Second Axial End

[0062] 125 Increasing diameter bushing section

[0063] 126 Radial outer base

[0064] 127 First end shoulder

[0065] 128 Second end shoulder

[0066] 131 First peripheral pressure mating part

[0067] 132 Second peripheral pressure mating part

[0068] 133 Third peripheral pressure mating part

[0069] 134 Fourth peripheral pressure mating part

[0070] 13 Radial clearance

[0071] 135 Radial clearance at the first axial end

[0072] 136 Radial clearance at the second axial end

[0073] 14 Axial clamping part

[0074] 141 First Axial Clamping Part

[0075] 142 Second Axial Clamping Part

[0076] 15-ring element

[0077] 16 Threaded connection

[0078] 17 Rotors

[0079] 18 nuts

[0080] 19 Radial discs

[0081] 20 turbines

[0082] 21 Compressor

[0083] 211 Compressor impeller

[0084] 22 Turbo

[0085] 221 Turbine impeller

[0086] 23 Motors

[0087] 231 One or more rotor magnets of an electric motor

[0088] 232 One or more stator magnets

[0089] 24 Balance Board

[0090] 25 coils

[0091] 30. Methods for suppressing torsional vibration of shafts

[0092] 31, 32 Flowchart frames illustrating embodiments of methods for suppressing torsional vibration of a shaft

[0093] axial length of the diameter-increasing bushing section

[0094] L Axial length of the integral bushing

[0095] D max Maximum diameter of the diameter-enlarging bushing section

[0096] D out Outer diameter of integrated bushing

[0097] D p1 The inner diameter of the integral bushing at the first peripheral press-fit portion

[0098] L p1The axial distance between the first peripheral pressing part and the first axial pressing part

[0099] D p2 The inner diameter of the integral bushing at the second peripheral press fit portion

[0100] L p2 The axial distance between the second peripheral pressing part and the second axial pressing part

[0101] D1 First diameter of the diameter-enlarging bushing section

[0102] D2 The second diameter of the diameter-increasing bushing section

[0103] The diameter of the d-axis

[0104] r radial direction

[0105] x-axis direction

Claims

1. A damping assembly (10) for suppressing torsional vibrations of a shaft (11), in particular of a main shaft of a turbomachine (20), the damping assembly (10) comprising: - an integral shaft sleeve (12) arranged around the shaft (11), the integral shaft sleeve (12) having an aspect ratio L / D out ≥ 2, wherein L is the axial length of the integral shaft sleeve (12), and wherein D out is the outer diameter of the integral shaft sleeve (12); an axial clamping portion (14) of the one-piece shaft sleeve (12); a first peripheral press-fit portion (131) between a first end portion (121) of the one-piece shaft sleeve (12) and the shaft (11); and a second peripheral press-fit portion (132) between a second end portion (122) of the one-piece shaft sleeve (12) and the shaft (11); wherein a radial gap (13) between the one-piece shaft sleeve (12) and the shaft (11) is provided between the first peripheral press-fit portion (131) and the second peripheral press-fit portion (132).

2. The damping assembly (10) according to claim 1, wherein The axial clamping portion (14) is provided by a first axial compression (141) at a first axial end (123) of the one-piece shaft sleeve (12) and a second axial compression (142) at a second axial end (124) of the one-piece shaft sleeve (12).

3. The damping assembly (10) according to claim 1 or 2, wherein The shaft (11) comprises a shaft shoulder portion (111) for providing a stop for the axial clamping portion (14) of the one-piece shaft sleeve (12), in particular the shaft shoulder portion (111) is provided on a turbine side of the main shaft of the turbomachine.

4. The damping assembly (10) according to claim 3, wherein A ring element (15), in particular a thrust ring, is provided between the shaft shoulder portion (111) and the one-piece shaft sleeve (12), in particular between the shaft shoulder portion (111) and the second axial end (124) of the one-piece shaft sleeve (12).

5. The damping assembly (10) according to any one of claims 1 to 4, wherein, The axial clamping portion (14) is provided by a preload of a threaded connection (16).

6. The damping assembly (10) of claim 5, wherein, The threaded connection (16) providing the preload is a threaded connection of a rotor (17) to the shaft (11) or a threaded connection of a nut (18) to the shaft, in particular the nut (18) is used to axially fix the rotor on the shaft (11).

7. The damping assembly (10) according to claim 6, wherein The rotor (17) is a compressor wheel (211).

8. The damping assembly (10) according to any one of claims 2 to 7, further comprising a radial disc (19), in particular a sealing disc, provided at the first axial end (123) of the one-piece shaft sleeve (12), in particular the radial disc (19) is provided between the rotor (17) and the first axial end (123) of the one-piece shaft sleeve (12).

9. The damping assembly (10) according to any one of claims 1 to 8, further comprising at least one of a third peripheral press-fit portion (133) between the one-piece shaft sleeve (12) and the shaft (11) and a fourth peripheral press-fit portion (134) between the one-piece shaft sleeve (12) and the shaft (11), in particular wherein the third peripheral press-fit portion (133) is provided at the first end portion (121) and in particular wherein the fourth peripheral press-fit portion (134) is provided at the second end portion (122).

10. The damping assembly (10) according to any one of claims 1 to 9, wherein, The one-piece bushing (12) has a diameter-increased bushing portion (125) having a maximum diameter D max and an axial length l, wherein the ratio D max / l is 0.54 ≤ D max / l ≤ 2.8, and / or wherein the ratio D max / L is 0.24 ≤ D max / L ≤ 0.38, wherein L is the total axial length of the bushing (12).

11. The damping assembly (10) according to any one of claims 1 to 10, wherein, The one-piece bushing (12) has a radially outer base (126) for one or more magnets (231) of an electric machine (23), in particular a permanent magnet electric machine, in particular the radially outer base (126) is provided at the enlarged diameter bushing portion (125) of claim 10.

12. The damping assembly (10) according to any one of claims 2 to 11, wherein, aspect ratio L p1 / D p1 ≥ 0.6, wherein L p1 is an axial distance between the first peripheral press fit portion (131) and the first axial pinch portion (141), and wherein D p1 is an inner diameter of the one-piece bushing (12) at the first peripheral press fit portion (131).

13. The damping assembly (10) according to any one of claims 2 to 12, wherein, aspect ratio L p2 / D p2 ≥ 0.6, wherein L p2 is an axial distance between the second peripheral press fit portion (132) and the second axial compression portion (142), and wherein D p2 is an inner diameter of the one-piece bushing (12) at the second peripheral press fit portion (132).

14. A turbomachine (20), in particular a turbocharger, comprising a damping assembly (10) according to any one of claims 1 to 12, in particular the shaft (11) connects a compressor wheel (211) of a compressor (21) with a turbine wheel (221) of a turbine (22).

15. The turbomachine (20) of claim 13, further comprising an electric machine (23), in particular a permanent magnet electric machine, provided between the compressor wheel (211) and the turbine wheel (221), in particular the electric machine (23) comprises one or more magnets (231) mounted on a radially outer base (126) of the one-piece bushing (12), in particular the one or more magnets (231) are provided between balance plates (24) mounted on the one-piece bushing.

16. A method (30) of suppressing torsional vibrations of a shaft (11), in particular of a main shaft of a turbomachine (20), the method (30) comprising suppressing (31) torsional vibrations by friction, in particular microfriction, between an integral shaft sleeve (12) provided around the shaft (11), the integral shaft sleeve (12) having an aspect ratio L / D out ≥ 2, wherein L is an axial length of the integral shaft sleeve (12), and wherein D out is an outer diameter of the integral shaft sleeve (12), the friction being provided at an interface of an axial clamping portion (14) of the integral shaft sleeve (12), at an interface between a first end portion (121) of the integral shaft sleeve (12) and the shaft (11) at a first peripheral press fit portion (131), and at an interface between a second end portion (122) of the integral shaft sleeve (12) and the shaft (11) at a second peripheral press fit portion (132), wherein a radial gap (13) between the integral shaft sleeve (12) and the shaft (11) is provided between the first peripheral press fit portion (131) and the second peripheral press fit portion (132).

17. The method (30) of claim 16, further comprising using (32) a damping assembly (10) according to any one of claims 1 to 13.

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