Connection adapter for the detachable connection of an impeller to a shaft, rotor unit formed thereby, and method for manufacturing a turbo compressor with such a rotor unit.

Abstract

The invention relates to a connecting adapter (1) for the detachable connection of an impeller (2) with a shaft (3) comprising, in particular, ceramic or tungsten carbide, to a rotor unit (4) rotatable about an axis of rotation (A) for a turbo compressor, wherein the connecting adapter (1) comprises an impeller section (20) for fixing the impeller (2) to the connecting adapter (1) and a shaft section (30) for fixing the connecting adapter (1) to the shaft (3), wherein the impeller section (20) comprises a first axial alignment means (21) for axial alignment and a first radial alignment means (22) for radial alignment of the impeller (2) on the connecting adapter (1), and the shaft section (30) comprises a second axial alignment means (31) for axial alignment and a second radial alignment means (32) for radial alignment of the shaft (3) on the connecting adapter (1).by which the impeller (2) and the shaft (3) can be fixed to the connecting adapter (1) in a predetermined axial and radial orientation relative to each other.

Description

[0001] The invention relates to a connecting adapter for the detachable connection of an impeller with a shaft, in particular comprising ceramic or tungsten carbide, or in particular consisting of ceramic or tungsten carbide, a rotor unit formed by the connection of the impeller with the shaft by the connecting element, and a method for manufacturing a turbo compressor with such a rotor unit.

[0002] Numerous turbomachines or turbocompressors with rotor units comprising an impeller and shaft are known from the prior art, with the impeller and shaft often being directly fixed to one another. Reference is made to DE 10 101 165 A1 and US 2015 / 0 198 043 A1 for the relevant prior art.

[0003] However, if one of the components, i.e., the impeller or the shaft, is made of certain materials, such as ceramic or a tungsten carbide alloy, or contains these materials in high concentrations, problems may arise in the connection of the impeller and shaft, as the necessary fastening means can no longer be easily designed or foreseen on the respective component.

[0004] If, for example, the impeller is to be fixed to the shaft with a screw, a hole cannot be drilled and an internal thread cut into a shaft made of ceramic or with a high ceramic content without a very high probability of destroying the shaft.

[0005] The invention is therefore based on the objective of overcoming the aforementioned disadvantages and enabling or simplifying the fixing of an impeller to a shaft, in particular one comprising ceramic or a tungsten carbide alloy.

[0006] This problem is solved by the combination of features according to claim 1.

[0007] According to the invention, a preferably one-piece connecting adapter is proposed for the detachable connection of an impeller with a shaft, which in particular comprises ceramic or tungsten carbide or a tungsten carbide alloy and in particular consists entirely of ceramic or a tungsten carbide alloy, to a rotor unit rotatable about an axis of rotation for a turbo compressor, in particular an oil-free turbo compressor, which is, for example, a high-speed turbo compressor. The term turbo compressor is used to encompass radial, axial, and diagonal compressors, so that the turbo compressor in this case can also be an axial compressor, a radial compressor, or a diagonal compressor.The connecting adapter comprises an impeller section for the impeller to be attached to the connecting adapter in a manner that is specifically designed to be detachable, and a shaft section for the connecting adapter to be attached to the shaft in a manner that is specifically designed to be permanent. "Detachable in a manner that is specifically designed to be detachable" means that the connection can be easily and non-destructively loosened and later re-established using appropriate hand tools, such as a wrench or Allen key. "Permanent" means that the connection can only be loosened with considerable effort, but preferably without causing damage.The impeller section has a first axial alignment means for axial alignment and a first radial alignment means for radial alignment of the impeller on the connecting adapter, and the shaft section has a second axial alignment means for axial alignment and a second radial alignment means for radial alignment of the shaft on the connecting adapter, by which the impeller and the shaft can be fixed to the connecting adapter in a predetermined axial and radial, i.e. in particular concentric, alignment with each other.

[0008] Because the impeller and shaft can be fixed to each other in a predetermined orientation, any balancing performed on a rotor unit formed by the impeller, the shaft and the connecting adapter is retained even if the fixing or connection, in particular of the impeller, is temporarily loosened during the assembly of the rotor unit or the turbo compressor and later restored.

[0009] In the context of this description, axial direction, radial direction and circumferential direction refer to the axis of rotation, unless otherwise specified in the specific case.

[0010] An advantageous variant of the connecting adapter provides that the impeller section has a thread for creating a screw connection with the impeller. This thread can be an internal thread extending axially along its longitudinal axis, allowing the impeller to be screwed to the internal thread via a screw or an external thread formed by the impeller. Alternatively, the thread can be an external thread extending axially along its longitudinal axis, allowing the impeller to be screwed to the external thread via a nut or an internal thread formed by the impeller.

[0011] When using a screw or a nut, it should be noted that the wheel is preferably pressed against the connecting adapter by these, i.e., fixed to it in a force-fit manner.

[0012] Furthermore, the shaft section may be designed to form or have a joining section configured as a mating component of a fit. The joining section may be configured as a pin, projecting axially with its longitudinal axis, for mating with a corresponding receptacle provided on the shaft, such that the connecting adapter can be permanently connected to the shaft via the fit formed by the pin and the receptacle. Alternatively, the joining section may be configured as a sleeve extending axially with its longitudinal axis or as a cup for mating with a corresponding projection provided on the shaft, such that the connecting adapter can be permanently connected to the shaft via the fit formed by the sleeve and the projection. The fit may be, in particular, a transition fit or an interference fit.

[0013] The impeller section can also be equipped with a first circumferential alignment device for aligning the impeller with the connecting adapter in a predetermined position. Additionally or alternatively, the shaft section can be equipped with a second circumferential alignment device for aligning the connecting adapter with the shaft in a predetermined position. Accordingly, the impeller and / or the shaft can be fixed to the connecting adapter in a predetermined circumferential orientation relative to each other by means of the first and / or second circumferential alignment device.

[0014] In a simple case, the first and / or the second circumferential guide can be provided as a marker by which the respective component can be brought into a predetermined orientation in the circumferential direction with a respective corresponding marker and then fixed in this orientation.

[0015] Alternatively, the first and / or second circumferential alignment device could also be, for example, a coding pin, for which a corresponding recess must be provided in the respective component, i.e., in the impeller or shaft. The functional reversal is also possible, so that the respective recess can be located on the connecting adapter and the coding pin on the respective component.

[0016] Furthermore, a further development of the connecting adapter is designed to extend at least with its impeller section in the axial direction into the impeller or to encompass the impeller radially outside, so that the connecting adapter overlaps with the impeller at least in its impeller section in the axial direction.

[0017] Furthermore, the connecting adapter can be designed to extend at least its shaft section axially into the shaft or to encompass the shaft radially outside, so that the connecting adapter overlaps the shaft at least in its shaft section axially.

[0018] Preferably, the impeller section and the shaft section are designed such that an axial overlap of the impeller fixed to the connecting adapter with the shaft fixed to the connecting adapter is created, i.e., the impeller and shaft overlap in the axial direction.

[0019] Furthermore, the connecting adapter can have a balancing section, provided or arranged particularly between the impeller section and the shaft section, for balancing the connecting adapter or a unit consisting of the connecting adapter and shaft, or a unit consisting of the connecting adapter and impeller, or the rotor unit. For this purpose, the balancing section includes a material removal mass, i.e., an excess of material designed for material removal, and / or interfaces for fixing balancing weights.

[0020] To ensure a thermal connection between the impeller and the shaft, the impeller section can be thermally connected to the shaft section, and the connecting adapter can be designed to connect the impeller to the shaft in a thermally conductive manner or for heat dissipation.

[0021] For the connecting adapter, materials such as steel, titanium or corrosion-resistant nickel-based alloys can be used, with the latter being particularly suitable an alloy widely marketed under the brand name Inconel at the time of application.

[0022] A further aspect of the invention relates to a rotor unit comprising an impeller, a shaft, and a connecting adapter according to the invention that connects the impeller to the shaft. The impeller and the shaft are aligned axially and radially, and preferably circumferentially, with respect to each other in a predetermined position and are fixed to each other in this position via the connecting adapter.

[0023] A further aspect of the invention relates to a method for manufacturing a turbo compressor, or an axial, radial, or diagonal compressor, with a rotor unit driven by an electric motor. According to the method, the impeller is fixed to the shaft in a predetermined orientation via the connecting adapter, and the resulting rotor unit is balanced. Subsequently, the impeller of the balanced rotor unit is removed from the connecting adapter, which can be done during the initial manufacturing of the turbo compressor or, for example, during later maintenance or repair. Particularly in the context of maintenance or repair, the connecting adapter with the shaft of the balanced rotor unit fixed to it remains in a housing of the turbo compressor or is inserted into such a housing, for example, during initial manufacturing.At a later point, the impeller is then fixed to the connecting adapter inserted with the rotor unit in the housing of the turbo compressor in the predetermined axial and / or radial orientation and / or circumferential orientation, so that the previously carried out balancing is retained despite temporary disassembly of the rotor unit.

[0024] The features disclosed above can be combined in any way, provided that this is technically possible and they do not contradict each other.

[0025] Other advantageous embodiments of the invention are characterized in the dependent claims or are described in more detail below together with the description of the preferred embodiment of the invention with reference to the figures. The figures show: Fig. 1 comprising a rotor unit, a first variant of a connection adapter; Fig. 2 a rotor unit comprising a second variant of a connection adapter.

[0026] The figures are schematic examples. Identical reference symbols in the figures indicate identical functional and / or structural features.

[0027] The Fig. 1 and Fig. Figures 2 each show a rotor unit 4 rotatable about a rotation axis A, which, however, provide differently designed connecting elements 1 with a corresponding impeller 2 and a shaft 3.

[0028] Regardless of the specific design, the connecting elements 1 each have a wheel section 20 and a shaft section 30.

[0029] The impeller 2 can be axially and radially aligned on the impeller section 20 via a first axial alignment means 21 designed as an axial stop and a first radial alignment means 22 designed as an (outer) fitting surface extending in the circumferential direction U.

[0030] Similarly, the shaft 3 can be aligned axially and radially on the shaft section 30 via a second axial straightening means 31 designed as an axial stop and a second radial straightening means 32 designed as an (inner) fitting surface of a sleeve 33 extending in the circumferential direction U.

[0031] The shaft 3, which is preferably made entirely or at least substantially of ceramic or tungsten carbide, is pressed into the sleeve 33 via a press or transition fit and thereby fixed with the connecting adapter 1.

[0032] According to the in Fig. In the variant shown in Figure 1, an internal thread is provided in the impeller section 20, into which a screw 5 can be screwed to fix the impeller 2.

[0033] In contrast, in Fig.2 adjacent to the first radial alignment means 22 designed as an (outer) fitting surface, an external thread is formed by the connecting adapter 1, on which a nut 6 can be screwed for fixing the impeller 2.

[0034] In order to be able to balance the rotor unit 4 or to pre-balance the rotor unit 4 before a subsequent final balancing, a balancing section 10 is provided in each case, at which material can be removed for balancing.

[0035] The invention is not limited in its implementation to the preferred embodiments specified above. Rather, a number of variants are conceivable which make use of the solution presented even in fundamentally different designs.

Claims

[1] Connection adapter (1) for the detachable connection of an impeller (2) with a shaft (3), in particular made of ceramic or tungsten carbide, to a rotor unit (4) for a turbocompressor, which can be rotated about a rotation axis (A), wherein the connecting adapter (1) has an impeller section (20) for fixing the impeller (2) to the connecting adapter (1) and a shaft section (30) for fixing the connecting adapter (1) to the shaft (3), wherein the impeller section (20) has a first axial aligning means (21) for axial alignment and a first radial aligning means (22) for radial alignment of the impeller (2) on the connecting adapter (1), and the shaft section (30) has a second axial aligning means (31) for axial alignment and a second radial aligning means (32) for radial alignment of the shaft (3) on the connecting adapter (1), by means of which the impeller (2) and the shaft (3) can be fixed to the connecting adapter (1) in a predetermined axial and radial alignment with respect to one another. [2] Connection adapter 1 according to claim 1, wherein the impeller section (20) has a thread for establishing a screw connection with the impeller 2, wherein the thread is an internal thread extending in particular with its longitudinal axis in the axial direction, so that the impeller (2) can be screwed to the internal thread via a screw (5) or an external thread formed by the impeller (2), or wherein the thread is an external thread extending in particular with its longitudinal axis in the axial direction, so that the impeller (2) can be screwed to the external thread by a nut (6) or an internal thread formed by the impeller (2). [3] Connection adapter 1 according to claim 1 or 2, wherein the shaft section (30) forms or has a joining section designed as a joining partner of a fit, wherein the joining section is designed as a pin, in particular with its longitudinal axis projecting in the axial direction, for joining with a receptacle provided on the shaft (3) and corresponding thereto, so that the connecting adapter (1) can be connected to the shaft (3) via the fit formed by the pin and the receptacle, or wherein the joining section is designed as a sleeve (33) extending in particular with its longitudinal axis in the axial direction for joining with a projection provided on the shaft (3) and corresponding thereto, so that the connecting adapter (1) can be connected to the shaft (3) via the fit formed by the sleeve (33) and the projection, and wherein the fit is in particular a transition fit or an interference fit. [4] Connection adapter 1 according to one of the preceding claims, wherein a first circumferential aligning means for aligning the impeller (2) on the connecting adapter (1) in a predetermined position is provided on the impeller section (20) and wherein a second circumferential aligning means is provided on the shaft portion (30) for aligning the connecting adapter (1) on the shaft (3) in a predetermined position, by means of which the impeller (2) and the shaft (3) can be fixed to one another on the connecting adapter (1) in a predetermined orientation in the circumferential direction (U). [5] Connection adapter 1 according to one of the preceding claims, which is designed to extend at least with its impeller section (20) in the axial direction into the impeller (2) or to encompass the impeller (2) radially outwardly, so that the connection adapter (1) overlaps with the impeller (2) in the axial direction at least in its impeller section (20). [6] Connection adapter 1 according to one of the preceding claims, which is designed to extend at least with its shaft section (30) in the axial direction into the shaft (3) or to encompass the shaft (3) radially outwardly, so that the connection adapter (1) overlaps with the shaft (3) in the axial direction at least in its shaft section (30). [7] Connection adapter 1 according to one of the preceding claims, wherein the impeller section (20) and the shaft section (30) are designed to produce an axial overlap of the impeller (2) fixable to the connection adapter (1) with the shaft (3) fixable to the connection adapter (1). [8] Connection adapter 1 according to one of the preceding claims, further comprising a balancing section (10) provided in particular between the impeller section (20) and the shaft section (30) for balancing the connecting adapter (1) or a unit comprising the connecting adapter (1) and the shaft (3) or a unit comprising the connecting adapter (1) and the impeller (2) or the rotor unit (4), wherein a mass designed for material removal and / or interfaces for fixing balancing weights are provided in the balancing section (10). [9] Connection adapter 1 according to one of the preceding claims, wherein the impeller section (20) is thermally conductively connected to the shaft section (30) and the connection adapter (1) is designed to thermally conductively connect the impeller (2) to the shaft (3). [10] Rotor unit (4) with an impeller (2), a shaft (3), and a connecting adapter (1) connecting the impeller (2) to the shaft (3) according to one of the preceding claims, wherein the impeller (2) and the shaft (3) are fixed to one another via the connecting adapter (1) in an axially and radially aligned manner. [11] Method for producing a turbocompressor with a rotor unit (4) driven by an electric motor according to the preceding claim, wherein the impeller (2) is fixed to the shaft (3) in a predetermined orientation via the connecting adapter (1) and the rotor unit (4) formed thereby is balanced, wherein the impeller (2) of the balanced rotor unit (4) is dismantled from the connecting adapter (1), wherein the connecting adapter (1) with the shaft (3) of the balanced rotor unit (4) fixed thereto remains or is inserted into a housing of the turbocompressor, and wherein the impeller (2) is fixed in the predetermined orientation to the connecting adapter (1) inserted with the rotor unit (4) in the housing of the turbocompressor.

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