COMPRESSOR WHEEL ARRANGEMENT AND METHOD FOR THE PRODUCTION OF A COMPRESSOR WHEEL ARRANGEMENT

Abstract

A compressor wheel arrangement for an electrically powered turbocharger, which can be connected with a rotor shaft of the turbocharger, having a compressor wheel made of a first metallic material, a shaft made of a second metallic material, which is tightly connected with the compressor wheel, at least one permanent magnet, which is non-rotatably arranged on the section of the shaft, in a ring-shaped area around a section of the shaft that extends behind the compressor wheel, between a casing and the shaft.

Claims

1. A compressor wheel arrangement for an electrically powered turbocharger, which can be connected to a rotor shaft of the turbocharger, having a compressor wheel made of a first metallic material, a shaft made of a second metallic material, which is tightly connected with the compressor wheel, at least one permanent magnet, which is non-rotatably arranged on the section of the shaft, in a ring-shaped area around the section of the shaft, this shaft section extending behind the compressor wheel, between a casing and the shaft.

2. The compressor wheel arrangement according to claim 1, wherein the permanent magnet is thermally coupled with the compressor wheel.

3. The compressor wheel arrangement according to claim 1, wherein the shaft is tightly connected to the compressor wheel by a friction-welded connection.

4. The compressor wheel arrangement according to claim 1, wherein the compressor wheel is formed of one part and the shaft has a first shaft section and a second shaft section, wherein the first shaft section, at the end of the shaft, and a recess of the compressor wheel, in which the first shaft section engages, form a shaft-hub connection and the second shaft section extends behind the compressor wheel.

5. The compressor wheel arrangement according to claim 1, wherein the compressor wheel is formed of at least two parts, with a blade section and a hub projection, and wherein the shaft has a first shaft section and a second shaft section, and the first shaft section, at the end of the shaft, and a recess of the hub projection, in which the first shaft section engages, form a shaft-hub connection and the second shaft section extends behind the compressor wheel.

6. The compressor wheel arrangement according to claim 4, wherein the shaft-hub connection is formed as a press-fit connection or as a shrink-fit connection.

7. The compressor wheel arrangement according to claim 4, wherein the first shaft section, at the end of the shaft, has a structure with elevations and/or indentations, in particular a structure with grooves.

8. The compressor wheel arrangement according to claim 1, wherein the shaft comprises a ferromagnetic material, in particular steel, and/or the compressor wheel comprises aluminium.

9. The compressor wheel arrangement according to claim 1, wherein the at least one permanent magnet us formed as a magnetic sleeve.

10. The compressor wheel arrangement according to claim 1, wherein an adhesive layer is arranged between the at least one permanent magnet and the shaft, as well as between the at least one permanent magnet and the compressor wheel.

11. The compressor wheel arrangement according to claim 1, wherein the casing is formed as a coil or as a sleeve.

12. A method for the manufacture of a compressor wheel arrangement for an electrically powered turbocharger, comprising: forming a blank by the assembly of a first component made of a first metallic material and a second component made of a second metallic material, so that the second component extends along a longitudinal axis of the blank, processing the blank via material-removing method steps in the same clamping device for the manufacture of a compressor wheel with a shaft protruding from the back of the first or second components respectively, or for the manufacture of a hub projection of an at least two-part compressor wheel with a shaft protruding from the back from the first and second components respectively, arranging at least one permanent magnet in a ring-shaped area around a section of the shaft that extends behind the compressor wheel, so that the at least one permanent magnet is fixed non-rotatably to the section of the shaft between a casing and the shaft.

13. The method according to claim 12, wherein the first component and the second component are connected by friction welding.

14. The method according to claim 12, wherein the second component has an end region and the first component has a recess, so that the end region that engages in the recess and the recess form a shaft-hub connection of the compressor wheel arrangement to be manufactured, which is in particular formed by press fitting or shrink-fitting.

15. The method according to claim 12, wherein the compressor wheel with blades is milled either before or after the arrangement of the at least one permanent magnet and the casing.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Some exemplary embodiments are, on the basis of the drawing, illustrated in more detail below. Here are shown:

[0044] FIG. 1 a sectional representation of a central region of an exemplary embodiment of an electrically powered turbocharger,

[0045] FIG. 2 a sectional representation of an exemplary embodiment of a compressor wheel arrangement,

[0046] FIG. 3 a sectional representation of a further exemplary embodiment of a compressor wheel arrangement,

[0047] FIG. 4 a three-dimensional representation of an exemplary embodiment of a first component of a blank,

[0048] FIG. 5 a three-dimensional representation of an exemplary embodiment of a second component of a blank,

[0049] FIG. 6 a three-dimensional representation of an exemplary embodiment of a blank with bonded first and second components,

[0050] FIG. 7 a three-dimensional representation of the further processed exemplary embodiment of a blank,

[0051] FIG. 8 a three-dimensional sectional view of an exemplary embodiment of a module with the further processed exemplary embodiment of a blank and further components,

[0052] FIG. 9 a further exemplary embodiment of a compressor wheel arrangement in an exploded view, and

[0053] FIG. 10 a sectional view of a further exemplary embodiment of a compressor wheel arrangement.

DETAILED DESCRIPTION

[0054] In the figures, components that are identical or have the same functional effect are labelled with the same reference numerals.

[0055] FIG. 1 shows a sectional representation of a central region of an exemplary embodiment of an electrically powered turbocharger. For the compressor and the turbine, the depiction focuses on a compressor wheel 49 and a turbine wheel 37 respectively. The surrounding compressor housing or turbine housing are, for the sake of clarity, not depicted.

[0056] The turbocharger comprises a rotor 31, which is rotatably mounted in a bearing apparatus 33. The rotor 31 comprises a compressor wheel arrangement 35, the turbine wheel 37 and a rotor shaft 39, the rotor shaft connecting the turbine wheel 35 with the compressor wheel arrangement 35. The bearing apparatus 33 comprises a bearing housing 41, in which radial and axial bearings 43, 45 for the rotor shaft 31 are arranged, as well as an oil feed 47, in order to provide an oil film for the bearings 43, 45.

[0057] The compressor wheel arrangement 35 comprises the compressor wheel 49 with integrated shaft 51, the shaft extending behind the compressor wheel 49 and being shorter than the rotor shaft 39. The term “integrated shaft” refers to the fixed connection, here as a shaft-hub connection 63, between compressor wheel 49 and shaft 51. A cylindrical recess 53 extends along a longitudinal axis of the compressor wheel arrangement 35. The rotor shaft 39 runs from the turbine wheel 37 through the bearing apparatus 33 and the compressor wheel arrangement 35. The latter is arranged outside the bearing apparatus 33 and is non-rotatably connected with the rotor shaft 39.

[0058] An electric motor 55 is arranged between the compressor wheel 49 and the bearing apparatus 33, said electric motor comprising stators 57 with coils and a sleeve-shaped permanent magnet 15. The magnet 15 is arranged non-rotatably on the shaft 51 of the compressor wheel arrangement 35. It is enclosed by a sleeve-shaped casing 17 on the outside, and covered by a covering disc 19 at the ends. The stators 57 with coils are arranged radially around the sleeve-shaped magnet 15.

[0059] During the operation of the turbocharger, the rotation of the turbine wheel 37, which is powered by exhaust gases from an internal combustion engine, causes the rotation of the compressor wheel 49, with which the air fed into the internal combustion engine is compressed. The rotation of the turbine wheel 37 is transferred to the compressor wheel arrangement 35 via the rotor shaft 39. The rotation of the compressor wheel can additionally or alternatively be caused by the electric motor 55, in which changing fields in the stators 57 set the permanent magnet 15, and with it the shaft 51 and the whole rotor 31 in rotation.

[0060] FIG. 2 shows a sectional representation of an exemplary embodiment of a compressor wheel arrangement 35 with a compressor wheel 49 and a shaft 51.

[0061] The shaft 51 is formed of a ferromagnetic material and is in particular steel and hollow. The compressor wheel 49 is made of aluminium or a material comprising aluminium. The compressor wheel 49 has a recess that goes right through it. The compressor wheel 49 has blades 59 on its front side, said blades being designed to compress air that is fed into the internal combustion engine. A hub projection 61 extends on the back of the compressor wheel 49, the inner diameter of which is widened in steps at the front. A section 7 at the end of the shaft 51 engages in the widened recess, so that a shaft-hub connection 63 is formed, which is designed to transfer the torque from the shaft 51 to the compressor wheel 49. Such a shaft-hub connection 63 can, for example, be formed as a press-fit connection or as a shrink fit connection, also called a press fit or shrink fit. With the press-fit connection, the engagement of the end region 7 in the recess accompanies a deformation, which leads to a force-fitting connection. With the shrink fitting, the components are assembled once heated, and the cooling leads to shrinking, and with it a force-fitting, fixed connection.

[0062] A sleeve-shaped permanent magnet 15 is arranged next to the shaft-hub connection 63 on the shaft 51, so that the facing end sides of the magnet 15 and the hub projection 61 of the compressor wheel 49 are adjacent. The magnet 15 and the compressor wheel 49 are thermally coupled. This can occur due to contact of the components or due to a thermal coupling agent. A covering disc 19 is arranged on the side of the permanently magnetic sleeve facing away from the compressor wheel 49. On the outside of the sleeve-shaped permanent magnet 15, a hollow cylindrical casing 17 is provided, which also extends over the covering disc 19 and the hub projection 61 of the compressor wheel 49. The casing 17 is formed as a sleeve, which has been pressed or shrunk. The sleeve can be metallic. Alternatively, it can be made of carbon.

[0063] Between the permanent magnet 15 and the adjacent surfaces of the components surrounding it, there is an adhesive layer 75, which not only forms a fixed connection, but also produces a thermal coupling, in particular to the compressor wheel 49 and to the shaft 15. As the permanent magnet 15 is usually made of a brittle material, its complete coverage with adhesive 75 and other components prevents damage at high speeds by the centrifugal forces acting on the magnet 15.

[0064] The described compressor wheel arrangement 35 is a module which is already balanced before assembly with the other components of the turbocharger, so that the observance of manufacturing tolerances is facilitated, in order to achieve smooth running.

[0065] FIG. 3 shows a further exemplary embodiment of the compressor wheel arrangement 35, the casing 17 of which differs from the one previously described. The following description concentrates on this aspect, in order to avoid repetition.

[0066] The casing 17 in this exemplary embodiment is a coil instead of a sleeve. The material for the coil is fibrous or strip-shaped. So that the coil does not slip off and fully covers the outside of the magnet 15, both the compressor wheel 49 and the covering disc 19 form walls 65 in sections, which restrict the axial expansion of the coil 17. The sections control the coil-shaped casing 17 with their position and width and height, so that the coil is radially flush with the compressor wheel 49 and the covering disc 19.

[0067] In the following, the manufacture of an exemplary embodiment of a compressor wheel arrangement 35 is described.

[0068] FIG. 4 shows an exemplary embodiment of a first component 1 of a blank, from which a compressor wheel 49 with integrated shaft 51, compressor wheel-shaft device for short, for an electrically powered turbocharger can be formed by machining. The compressor wheel 49 of the compressor wheel-shaft device is formed from the first component 1.

[0069] The first component 1 comprises a first metal. In view of its later use as a compressor wheel 49, the first metal is advantageously aluminium or an aluminium alloy, so that the future compressor wheel 49 is lightweight and stable.

[0070] The first component 1 has a disc-shaped, rotationally symmetrical original form, which is referred to as a circular blank. An edge of the cross-section of the disc-shaped first component 1 rests on an external contour of the compressor wheel 49 that is later to be formed from said first component, but extends beyond it due to the removal of material in production that is still to follow. The first component 1 has a recess 3 with a circular cross section in the middle. The recess 3 extends along the rotational axis and is designed as a blind hole formed by drilling.

[0071] FIG. 5 shows an exemplary embodiment of a second component 5 of a blank, from which a compressor wheel 49 with integrated shaft 51 for an electrically powered turbocharger can be formed by machining. The shaft 51 of this compressor wheel-shaft device is formed from the second component 5.

[0072] The second component 5 is made of a second metal. In view of its later use as a shaft 51 of an electric motor, the second metal is preferably a ferromagnetic material, in particular steel. The second component 5 is combined with the first component 1 to form the blank.

[0073] The second component 5 is stick-shaped and has a cylindrical original form. An end region 7 of the second component 5, which is pressed into the recess 3 of the first component 1 during its assembly, is rounded on the front side and has external toothing, with longitudinally extending grooves 9. The grooves 9 extend into the area that is pressed into the recess 3. They can also extend beyond that. Advantageously, the grooves are not sharp-edged, rather they are rounded, so that no high notch stress occurs.

[0074] The end region 7 is designed in such a way that it can be pressed into the recess 3 of the first component 1, so that the end region 7 and the recess 3 form a press-fit connection. The bottom of the recess 3 formed as a blind hole forms a stop for the end region 7 that is pressed into it. The highest diameter of the end region 7 has an oversized fit in relation to the diameter of the recess 3. Due to the oversizing, the recess 3 is elastically widened and the end region 7 is compressed, which is further supported by the structure of the end region 7 with the grooves 9. A polygon-shaped cross section of the end region in an alternative exemplary embodiment would likewise have this assisting effect. Due to the deformations during widening and pressing, contact pressure is created, which, as a fixed, force-fitting press-fit connection between the end region 7 and the recess 3, is suited to transfer a torque from the first component 1 to the second component 5. Due to the press-fit connection, the shaft-hub connection of the future compressor wheel 49 and the shaft 51 is already formed before the completion of the compressor wheel 49 and the shaft 51, the shaft-hub connection being suited to transfer a torque form the shaft 51 to the compressor wheel 49. In an alternative exemplary embodiment, shrink-fitting is used for forming the shaft-hub connection.

[0075] FIG. 6 shows a three-dimensional depiction of an exemplary embodiment of a blank 11, formed from a first and a second component 1, 5, which are connected by a press-fit connection. From such a blank 11, a compressor wheel 49 with integrated shaft 51 for an electrically powered turbocharger is manufactured, using machining. The compressor wheel 49 is manufactured from the first component 1, and the shaft 51 is manufactured from the second component 5.

[0076] The blank 11 is a hybrid blank, made of the bonded first and second components 1, 5. The longitudinal axis 13 of the blank 11 is the symmetrical axis of the blank 11 and runs through the recess 3 and along the stick-shaped second component 5. In this exemplary embodiment, the grooves 9 of the external toothing extend over the end region 7 that is pressed into the recess 3, so that they are still visible under the pressed-on first component 1.

[0077] As the blank 11 is further processed in a milling machine, the tightly connected first and second components 1, 5 are processed together, so that the compressor wheel 49 and the shaft 51 are formed from the same blank 11, without releasing the shaft-hub connection already formed through the press-fit connection between the future shaft and the future compressor wheel in production. The shaft-hub connection is designed to transfer torque and power from the turning shaft to the compressor wheel in the completed module. The step of assembling the finished compressor wheel and finished shaft is thereby eliminated, so that dimensional variations accompanying assembly are avoided.

[0078] When pressing together the first and the second components 1, 5, asymmetries that can arise are largely eliminated by the subsequent removal of material to form the compressor wheel 49 with integrated shaft 51. As the steps of further processing the blank 11 can be done in the same clamping device, accumulating dimensional variations that would occur through several clamping steps are avoided.

[0079] FIG. 7 shows a three-dimensional representation of an exemplary embodiment of a further processed blank, in which a hole has been bored into the end face of the second component 5 that is facing away from the first component 1, in order to form a hollow shaft. Additionally, the protruding external toothing has been removed by turning or milling, and the outer contour of the blank has been brought into the shape of the outer contour at least of the shaft 51 of the future compressor wheel-shaft device. In a subsequent milling step, blades 59 of the compressor wheel 49 are also formed. In this milling step, the outer contour of the compressor wheel 49 can still be adjusted.

[0080] FIG. 8 shows a three-dimensional sectional representation of an exemplary embodiment of a module with the further-processed exemplary embodiment of the blank from FIG. 7 and further components for the powering of the compressor wheel 49 by electric motor, the blades of the compressor wheel not yet having been formed.

[0081] In the further-processed blank, the press-fit connection 21 of the first and the second components 1, 5 forms a fixed shaft-hub connection between the shaft and the future compressor wheel. The second component 5 has been bored out, in order to form a hollow shaft. Further components of the electric motor have already been mounted. The shaft formed from the second component 5 is arranged in a hollow cylindrical magnet 15, which is placed in a casing 17 formed as a sleeve. On the front sides of the magnet 15, washers 19 are provided. The outer washer 19 serves as a covering disc. The washer 19 between the magnet 15 and the future compressor wheel forms a thermal coupling. Alternatively, instead of the washer 19, a thermal coupling can be made by contact, adhesive or thermally conductive paste.

[0082] The manufacturing steps still to follow comprise milling, in order to form the compressor wheel 49 with its blades 59 in the module, and the balancing of the module. In an alternative production, milling takes place, in order to form the compressor wheel 49 and its blades 59 in the module, before the assembly of the magnet, the casing and the washers.

[0083] The manufacture of a further exemplary embodiment of a compressor wheel device from a hybrid blank comprises lathe machining of a contour side and machining of the future shaft. The lathe machining of the back of the compressor wheel and the boring of the future compressor wheel with integrated shaft then follow. Adhesive is applied to the shaft and/or to the magnet, and the magnet and the covering disc are joined, the latter in particular by thermal joining. The casing is assembled, for example by carbon pressing or winding. After the hardening of the adhesive and the assembly, the blades of the compressor wheel are milled and the assembled rotor is balanced with the compressor wheel arrangement. Washing then takes place. Alternatively, the step in which the blades of the compressor wheel are milled is brought forward before the assembly of the further components, that is before the application of the adhesive.

[0084] FIG. 9 shows a further exemplary embodiment of a compressor wheel arrangement in an exploded view.

[0085] The compressor wheel arrangement comprises a two-part compressor wheel 49 with a blade section 67 and a hub projection 61, which are separate components. They are made of aluminium, or an alloy comprising aluminium. The blade section 67 is the front region of the compressor wheel 49 with the blades 59. On the back side of this is provided the hub projection 61. The recess 3 of the hub projection 61 has a stepped cross-sectional widening. Both the blade section 67 and the hub projection 61 have an axial recess going all the way through them for the rotor shaft 39, which connects the blade section 67 and the hub projection 61 in the mounted compressor wheel arrangement 35, so that the blade section 67 and the hub projection 61 are thermally coupled. This can be done by contact between the components 67, 61 or with an adhesive or a thermally conductive paste between the components 67, 61.

[0086] The compressor wheel arrangement 35 further comprises a hollow shaft 51, a sleeve-shaped magnet 15, a covering disc 19 and a casing 17 formed as a carbon sleeve. Alternatively, the casing 17 can be formed as a coil. The shaft 51 has an end region 7, which engages in the recess 3 of the hub projection 61 and abuts the step, so that a shaft-hub connection is formed. The connection can be, for example, a press-fit connection or a shrink-fit connection, as described in relation to the previous exemplary embodiments. The sleeve-shaped magnet 15 and the covering disc 19 that is facing away from the compressor wheel 49 on the end face are arranged between the sleeve-shaped casing 17 and the shaft 51.

[0087] Besides the fact that the compressor wheel 49 is formed in two parts and its components 67, 61 can be separately manufactured, the compressor wheel arrangement 35 can be manufactured similarly to the exemplary embodiments described earlier. The production steps previously described in relation to the compressor wheel, however, only concern the hub projection 61 in this exemplary embodiment. The hybrid blank, from which the hub projection 61 with integrated shaft 51 is manufactured, has, in comparison to the previously described manufacture, a smaller circular blank, from which only the hub projection 61 is produced. The blade section 67 is made separately, also comprising the milling of the blades 59, and is only rotationally joined to the hub projection 61 with integrated shaft 51 and the components arranged on it during the assembly on the rotor shaft 39.

[0088] This exemplary embodiment makes the magnetisation and the joining of the magnet 15 easier, due to the smaller dimensions of the hub projection 61 with integrated shaft 51. However, due to the additional components of the two-part compressor wheel 49, it can be more difficult to adhere to manufacturing tolerances. The manufacture becomes more complicated, in particular in the assembly of the turbocharger. The balancing is also more complicated than with the one-part compressor wheel 49 that has been described in previous exemplary embodiments.

[0089] FIG. 10 shows a further exemplary embodiment of a compressor wheel arrangement 35 in a sectional view.

[0090] The one-part compressor wheel 49 made of aluminium or an alloy comprising aluminium tapers to a base 71 on the back, the diameter of which corresponds to that of the magnet 15. The hollow shaft 51 is connected to the base 71 by a friction-welded connection 73. The sleeve-shaped magnet 15 and the front covering disc 19 are arranged on the shaft 51 and are surrounded on the outside by the casing 17, which extends beyond the base 71. The casing 17 can be formed as a sleeve shape or as a coil. Between the magnet 15 and the other components, in particular the base of the compressor wheel, there is an adhesive layer 75 which serves as a thermal coupling agent.

[0091] The manufacture of this exemplary embodiment occurs similarly to what has been described previously; however, the blank for the machining manufacture is formed by friction welding between a first and second component. Lathe machining of the blank then takes place, both for the round blank as the first component and also for the second component connected to it. An adhesive 75 is then applied to the shaft 51 and the sleeve-shaped magnet 15 is attached. The covering disc 19 is attached, for example by thermal joining. Then the casing 17, which is formed as a sleeve, is attached. After the adhesive 75 has hardened, the blades 59 of the compressor wheel 49 are milled. The balancing takes place after the assembly of the compressor wheel arrangement 35 and rotor shaft 39 Then the washing takes place.

[0092] Although the present invention has been described above and is defined in the accompanying claims, it should be understood that the invention can also alternatively be defined in compliance with the following embodiment:

[0093] Blank (11) for the machining manufacture of a compressor wheel with integrated shaft for an electrically powered turbocharger, comprising a first component (1) made of a first metallic material with a recess (3), in which an end region (7) of a second component (5), made of a second metallic material, engages, so that the end region (7) and the recess (3) form a press-fit connection (21) or shrink-fit connection and the second component (5) extends along a longitudinal axis (13) of the blank (11), which also runs through the recess (3). [0094] 1. Blank (11) according to embodiment 1, wherein the first component (1) has an original form that is rotationally symmetrical relative to the longitudinal axis. [0095] 2. Blank (11) according to embodiment 1 or 2, wherein the first component (1) has a disc-shaped original form, the maximum diameter of which is larger than its maximum thickness. [0096] 3. Blank (11) according to one of the preceding embodiments, wherein an edge of the cross-section of the first component (1) has a curved shape, which is based on the external contour of the compressor wheel to be manufactured. [0097] 4. Blank (11) according to one of the preceding embodiments, wherein the second component (5) is stick-shaped and its end region (7) is rounded on the front face. [0098] 5. Blank (11) according to one of the preceding embodiments, wherein the end region (7) is a structure with elevations and/or indentations, in particular a structure with grooves (9). [0099] 6. Blank (11) according to one of the preceding embodiments, wherein the end region (7) has an external toothing with longitudinal grooves (9). [0100] 7. Blank (11) according to one of the preceding embodiments, wherein the end region (7) has a polygon-shaped cross section. [0101] 8. Blank (11) according to one of the preceding embodiments, wherein the second component (5) is steel. [0102] 9. Blank (11) according to one of the preceding embodiments, wherein the first component (1) comprises aluminium. [0103] 10. Compressor wheel with integrated shaft for an electrically powered turbocharger, which is machined out of the blank (11) according to one of the preceding claims, so that the press-fit connection (21) or the shrink-fit connection forms a shaft-hub connection between the shaft, made of the second material, and the compressor wheel, made of the first material. [0104] 11. Electrically powered turbocharger having a compressor wheel with integrated shaft, according to embodiment 11. [0105] 12. Method for the manufacture of a compressor wheel with integrated shaft for an electrically powered turbocharger, having the steps: formation of a blank (11) by assembling a first component (1), made of a first metallic material, with a recess (3) and a second component (5), made of a second metallic material, which has an end region (7), so that the end region (7) that engages in the recess (3) and the recess (3) form a press-fit connection (21) or a shrink-fit connection, and the second component (5) extends along a longitudinal axis (13) of the blank (11), said axis also running through the recess (3), and processing of the blank (11) by machining methods, in the same clamping device as used for the manufacture of the compressor wheel with integrated shaft for an electrically powered turbocharger.

[0106] Alternatively or additionally, the above embodiments can also refer to a hub projection with integrated shaft of a compressor wheel with at least two parts, instead of to the compressor wheel with integrated shaft.

[0107] The features above and those specified in the claims, as well as those that can be taken from the illustrations, can advantageously be implemented both individually and in different combinations. The invention is not limited to the described exemplary embodiments, but rather it is modifiable in a number of ways, within the scope of those skilled in the art.

REFERENCE NUMERALS

[0108] 1 first component [0109] 3 recess [0110] 5 second component [0111] 7 end region [0112] 9 groove [0113] 11 blank [0114] 13 longitudinal axis [0115] 15 magnet [0116] 17 sleeve [0117] 19 washer [0118] 21 press-fit connection [0119] 31 rotor [0120] 33 bearing device [0121] 35 compressor wheel arrangement [0122] 37 turbine wheel [0123] 39 rotor shaft [0124] 41 bearing housing [0125] 43 radial bearing [0126] 45 axial bearing [0127] 47 oil feed [0128] 49 compressor wheel [0129] 50 shaft [0130] 53 recess [0131] 55 electric motor [0132] 57 stator [0133] 59 blade [0134] 61 hub projection [0135] 63 shaft-hub connection [0136] 65 wall [0137] 67 blade section [0138] 71 base [0139] 73 friction-welded connection [0140] 75 adhesive