DE102015216319A1 - Turbocharger rotor for an exhaust gas turbocharger and turbocharger - Google Patents

Abstract

The invention relates to a turbocharger rotor (10) for an exhaust gas turbocharger having an exhaust gas turbocharger (71) and an exhaust gas turbocharger (70) with such a turbocharger rotor (10), wherein the turbocharger rotor (10) has at least one rotor shaft (30) a turbine-side shaft end (31) and a compressor-side shaft end (32), a turbine runner (50) connected non-rotatably to the turbine-side shaft end (31) and a compressor runner (20) connected in a rotationally fixed manner to the compressor-side shaft end (32) characterized in that the non-rotatable connection of the compressor impeller (20) to the compressor-side shaft end (32) comprises a weld joint (65) made in a friction-stir welding process.This arrangement has the advantages of providing a positive-lock connection between the compressor impeller and the rotor shaft is made, whereby a slippage of the compaction terlaufrades is reliably prevented

Description

The invention relates to a turbocharger rotor and an exhaust gas turbocharger with such a turbocharger rotor, wherein the turbocharger rotor has at least one rotor shaft, a turbine wheel rotatably connected to the turbine end and a compressor rotor rotatably connected to the compressor side shaft end.

Exhaust gas turbochargers with corresponding turbocharger rotors are increasingly used to increase performance in automotive internal combustion engines. This happens more frequently with the aim to reduce and the combustion engine with the same or even increased performance in size and weight at the same time the consumption and thus in this respect to reduce in view of increasingly stringent legal requirements, the CO ₂ emissions. The operating principle is to use the energy contained in the exhaust gas flow to increase the pressure in the intake tract of the engine and thus to better fill the combustion chamber with air-oxygen and thus implement more fuel, gasoline or diesel, per combustion process, so to increase the performance of the internal combustion engine.

An exhaust gas turbocharger has for this purpose a turbine arranged in the exhaust gas line of the internal combustion engine with a turbine runner driven by the exhaust gas flow and a compressor arranged in the intake tract with a compressor runner building up the pressure. Turbine rotor and compressor impeller are rotatably secured to the opposite ends of a rotor shaft and thus form the turbocharger rotor, which is rotatably mounted with its rotor shaft in a bearing assembly arranged between the turbine and compressor. Thus, with the aid of the exhaust gas mass flow, the turbine wheel and the rotor shaft in turn driven the compressor and the exhaust gas energy used to build up pressure in the intake.

For example, an exhaust gas turbocharger has for this purpose a turbine arranged in the exhaust gas line of the internal combustion engine with a turbine runner driven by the exhaust gas flow and a compressor arranged in the intake tract with a compressor runner building up the pressure. Turbine wheel and compressor wheel each have a matched to the application blading and are rotatably secured to the opposite ends of a common rotor shaft with which they form the so-called turbocharger rotor. The turbocharger rotor is mounted with its rotor shaft radially and axially rotatably in a bearing unit arranged between the turbine and the compressor. Thus, with the aid of the exhaust gas mass flow, the turbine wheel and the rotor shaft in turn driven the compressor and the exhaust gas energy used to build up pressure in the intake.

The structural design of a conventional exhaust gas turbocharger usually requires a multi-part construction of the turbocharger rotor, as in 1 illustrated by an example. At the same time, considerable torques must be transmitted via the rotor shaft at very high rotational speeds (a few tens of thousands to more than 100,000 revolutions per minute). In addition, the turbocharger rotor 30 during operation, in particular on the side of the turbine wheel 31 a thermal cycling with temperatures up to 1000 ° C applied. Furthermore, the moment of inertia of the turbocharger rotor must be minimized in order to ensure a fast speed adjustment to the changing operating conditions.

The resulting requirements require the use of selected materials and a robust bearing of the turbocharger rotor 30 , For example, the turbine wheel 31 made of a lightweight, high temperature resistant material, such as a titanium aluminide alloy. The rotor shaft 32 is made of steel because of the required wear resistance and the compressor impeller 1 For example, is made of an aluminum alloy to ensure a low weight and thus a low moment of inertia of the compressor impeller in operation. The turbine wheel 31 and the rotor shaft 32 are usually materially firmly connected to a component. The compressor impeller 1 By design, however, can be mounted and fixed on the rotor shaft only during assembly of the exhaust gas turbocharger together with the other components mentioned below.

The bearing of the usually consisting of a steel material rotor shaft 32 is commonly used as a radial plain bearing, for example, with floating radial bushings 34 executed and is supplied via a lubricant supply with lubricant. On the rotor shaft 32 are accordingly two radial bushings 34 in one by a bearing spacer sleeve 33 arranged certain axial distance. Furthermore, on the rotor shaft 32 a sealing ring bush 35 for the sealing of the oil chamber in the bearing housing with respect to the compressor housing of the exhaust gas turbocharger, a thrust washer 36 and a thrust bearing confining disc 37 , for supporting the turbocharger rotor against axial forces occurring during operation, between a shaft shoulder 32a and the compressor impeller 1 arranged. The sealing ring bush 35 , the thrust washer 36 and the thrust bearing confining disc 37 are together with the compressor impeller 1 with the help of a shaft nut 40 and the threaded stem 38 on the rotor shaft 32 tightened.

Such a structure of the turbocharger rotor is for example also from the document DE 10 2009 060 056 A1 known. Also the patent application DE 10 2013 213 023.6 discloses such a construction, in which, moreover, the sealing ring bush, the thrust washer 36 and the thrust bearing limiting element 37 are combined to form a component, this component is additionally equipped with an internal thread for additional clamping against the shaft shoulder. In such concepts, it comes due to the setting behavior and the different thermal expansion of the individual components, especially in the thermal cycling occurring during operation, sometimes to ease the connection to the total failure of the turbocharger rotor.

document US 4,705,463 discloses a compressor rotor for turbochargers, to the hub of which a cylindrical bushing component is connected by means of a friction-welded connection. The bushing component has a concentrically arranged threaded bore for connection to a rotor shaft. As a result, a hole in the compressor wheel hub and thus a weakening of the mechanical stability is avoided. The compressor impeller is made of an aluminum alloy, the female component is made of machine steel. However, it is known to the person skilled in the art that frictional welding connections between aluminum alloys and steel can frequently lead to residual stresses, cracking and embrittlement of the material in the connection region due to the high temperatures and different thermal expansion coefficients of the various materials.

The invention is therefore based on the object to provide a turbocharger rotor and an exhaust gas turbocharger with increased reliability and durability available.

The objects underlying the invention are achieved with the features of the subject invention according to the main claim with respect to a turbocharger rotor and the features of the independent claim with respect to the exhaust gas turbocharger. The dependent claims represent advantageous embodiments and modifications of the invention.

Accordingly, a turbocharger rotor is proposed for a turbocharger having an exhaust gas turbine and a fresh air compressor, wherein the turbocharger rotor has at least one rotor shaft with a turbine end shaft end and a compressor side shaft end, a turbine wheel rotatably connected to the turbine end and a compressor impeller rotatably connected to the compressor end shaft end , The turbocharger rotor is characterized in that the rotationally fixed connection of the compressor impeller to the compressor-side shaft end has a welded connection produced in a friction-stir welding process.

The exhaust gas turbocharger according to the invention for an internal combustion engine of a motor vehicle with an exhaust gas turbine a fresh air compressor and a bearing housing arranged therebetween is characterized in that it has a turbocharger rotor according to the invention.

The inventive design of the turbocharger rotor and the exhaust gas turbocharger has the advantage that a secured against loosening connection between the compressor impeller and rotor shaft is made, whereby slipping of the compressor impeller and optionally additional functional parts such as sealing bush, thrust washer, thrust bearing boundary plate and Ölabweisscheibe together with the compressor impeller reliably prevented. The secure connection between the compressor impeller and rotor shaft is made regardless of the material from the compressor impeller and rotor shaft, as can be connected by the friction-stir welding process and different materials reliably and permanently cohesively.

Advantageous embodiments of the invention are disclosed in the subclaims.

Embodiments and developments of the invention will be explained in more detail below with reference to the figures in the drawing.

Show it:

1 a turbocharger rotor according to the invention with the essential components and additional functional parts mounted on the rotor shaft, in sectional view;

2 an enlarged section Z of the compressor-side shaft end of the turbocharger rotor 1 in section and front view showing an embodiment of the welded connection between the compressor impeller and the rotor shaft produced by the friction stir welding method;

3 a further enlarged section Z of the compressor-side shaft end of the turbocharger rotor 1 in section and front view to illustrate another embodiment of the friction-stir welding process manufactured weld joint for mounting the compressor impeller on the rotor shaft;

4 a schematic representation of the manufacturing process of a friction-stir welded joint;

5 a simplified schematic representation of an embodiment of an exhaust gas turbocharger according to the invention in combination with a turbocharger rotor according to the invention.

Function and designation same parts are provided in the figures with the same reference numerals.

In 1 is a turbocharger rotor according to the invention 10 shown. The functional parts mounted from the compressor side are shown in section, whereas the rotor shaft 30 and the associated turbine runner 50 are shown uncut. The essential components of the turbocharger rotor 10 are the turbine wheel 50 , the rotor shaft 30 and the compressor impeller 20 , turbine impeller 50 and compressor impeller 20 are each rotationally fixed and axially in fixed position with the rotor shaft 30 connected.

The compressor impeller 20 has an impeller blading 21 and an impeller hub 22 with a turbine runner 50 facing inner end face 24 and a turbine runner 50 facing away from the outer end face 25 and a central through-hole 23 , for receiving the rotor shaft 30 on. The rotor shaft 30 penetrates the through hole 23 at full length, leaving the compressor-side shaft end 32 the rotor shaft 30 plan with the outer end face 25 of the compressor impeller 20 completes or surpasses them slightly.

Other functional components are between the turbine runner 50 and compressor impeller 20 on the rotor shaft 30 assembled. These are two radial bearing bushes 40 for the rotary bearing of the turbocharger rotor 10 in a bearing housing of an exhaust gas turbocharger, a bearing spacer sleeve 41 between the two radial bearing bushes 40 , which specifies the axial distance between the radial bearing bushes. For axial bearing of the turbocharger rotor are a thrust washer 46 and a thrust bearing confining disc 47 and for sealing the storage area relative to the compressor area of the exhaust gas turbocharger a sealing bushing 45 on the rotor shaft 30 between a wave shoulder 34 and the inner end face 24 of the compressor impeller 20 clamped against rotation.

In the 1 Detail Z marked with a circle contains the non-rotatable connection between the compressor impeller 20 and the compressor side shaft end 32 the rotor shaft 30 , which is a welded joint made in a friction-stir welding process 65 having. Two different versions of this non-rotatable connection are in the 2 and 3 shown as a detail Z enlarged.

2 shows on the basis of the detail Z in section (left half of the picture) and in front view of the compressor end of the shaft 32 Her (right half of the picture) an embodiment of a friction-stir welded joint 65 having rotationally fixed connection between the compressor impeller 20 and the compressor-side rotor shaft end 32 , This is characterized in that the compressor impeller 20 an impeller hub 22 with a centrally arranged through hole 23 , an inner end face facing the turbine runner 24 (not shown here) and a turbine wheel facing away from the outer end face 25 and that the compressor-side shaft end 32 a compressor-side shaft end face 33 having.

The rotor shaft 30 is from the inner end face 24 the impeller hub 22 so far into the through hole 23 the impeller hub 22 inserted that the compressor side shaft end face 33 with the outer end face 25 the impeller hub 22 lies in a plane and an annular gap 26 between the compressor side shaft end 32 and the through hole 23 is trained. Here, the welded joint produced in the friction-stir welding process 65 as a continuous continuous connection seam (see upper half in the front view) or as individual separate connection seam sections (see lower half in the front view) in the region and along the annular gap 26 educated.

The in the compressor side shaft end 32 introduced threaded hole 37 used for mounting purposes, such as the clamping of the rotor shaft 30 under tension during the execution of the friction-stir welding process, for example, a bias for clamping the functional components sealing bushing 45 , Thrust washer 46 and thrust bearing limiting disc 47 between wave shoulder 34 and inner face 24 to ensure the compressor impeller.

3 shows on the basis of the detail Z in section (left half of the picture) and in front view of the compressor end of the shaft 32 Her (right half of the picture) another embodiment of a friction-stir welded joint 65 having rotationally fixed connection between the compressor impeller 20 and the compressor-side rotor shaft end 32 , This is characterized in that the compressor-side shaft end 32 the rotor shaft 30 an external thread 38 having self-locking thread pitch and that the compressor impeller 20 an impeller hub 22 with a centrally arranged through hole 23 , one of the turbine runner 50 facing inner end face 24 and a turbine runner 50 facing away from the outer end face 25 having, wherein from the outer end face 25 fro a threaded insert 27 with an external thread 38 the rotor shaft 30 corresponding internal thread concentric to the through hole 23 in a receiving recess 29 the impeller hub 22 is inserted. Here is the rotor shaft 30 from the inside front 24 the impeller hub 22 into the through hole 23 inserted and stands with the threaded insert 29 in screw connection, wherein the compressor impeller 22 by means of the screw connection against a shaft shoulder 34 the rotor shaft 30 rotatably clamped. The threaded insert face 28 lies with the outer end face 25 the impeller hub 22 in a plane being between the outer shell of the threaded insert 27 and the receiving recess 29 an annular gap is formed. For non-rotatable connection of the impeller hub 22 with the threaded insert 27 is a weld joint made in the friction stir welding process 65 as a continuous connecting seam (see upper half in the front view) or as a single separate Verbindungsnahtabschnitte (see lower half in the front view) in the region and along the circumference of the annular gap 26 educated.

• 1.) Der Gewindeeinsatz 27 wird mittels Reib-Rühr-Schweißverfahrens vor der eigentlichen Montage des Turboladerläufers mit dem Verdichterlaufrad 20 verschweißt. Das Verdichterlaufrad 20 wird dann wie eine Wellenmutter, mit einem vorbestimmten Anzugsmoment, aufgeschraubt und erzeugt dadurch die Vorspannung im Wellenverband. Zu diesem Zweck kann das Verdichterlaufrad 22 Merkmale, zum Beispiel eine Schlüsselweite SW aufweisen (siehe 3, rechte Darstellung), die geeignet sind ein Festschraubmoment mit einem korrespondierenden Werkzeug auf das Verdichterlaufrad zu Übertragen. Dadurch werden die sich zwischen einer Wellenschulter 34 und der Laufradnabe 22 angeordneten weiteren Funktionsteile, wie z. Bsp. Dichtungsbuchse 45, Axiallagerscheibe 46 und Axiallager-Begrenzungsscheibe 47 zwischen Laufradnabe 22 und Wellenschulter 34 eingespannt
• 2.) Der Gewindeeinsatz 27 wird erst nach dem Aufschieben des Verdichterlaufrades 20 auf das Außengewinde 38 des verdichterseitigen Wellenendes 32 geschraubt und mit einem entsprechenden Anzugsmoment festgezogen, wodurch das Verdichterlaufrad 20 zusammen mit den weiteren Funktionskomponenten, z. B. Dichtungsbuchse 45, Axiallagerscheibe 46 und Axiallager-Begrenzungsscheibe 47 gegen die Wellenschulter 34 eingespannt werden. Zu diesem Zweck kann der Gewindeeinsatz 27 Merkmale, zum Beispiel Bohrungen 28a in der Gewindeeinsatzstirnfläche 28, aufweisen (siehe 3, linke Darstellung), die geeignet sind ein Festschraubmoment mit einem korrespondierenden Werkzeug auf den Gewindeeinsatz 27 zu übertragen. Nach dem Festziehen des Gewindeeinsatzes 27 wird dieser dann mittels einer im Reib-Rühr-Schweißverfahren hergestellte Schweißverbindung 65 in der oben beschriebenen Art mit dem Verdichterlaufrad 20 verbunden.

In the manufacture or assembly of a turbocharger rotor of the aforementioned embodiment, two different variants of the assembly process result:

• 1.) The thread insert 27 is done by means of friction-stir welding process before the actual assembly of the turbocharger rotor with the compressor impeller 20 welded. The compressor impeller 20 is then screwed like a shaft nut, with a predetermined torque, thereby creating the bias in the wave structure. For this purpose, the compressor impeller 22 Features, for example, have a key width SW (see 3 , right-hand illustration), which are suitable for transmitting a screwing torque with a corresponding tool to the compressor impeller. This will be between a wave shoulder 34 and the impeller hub 22 arranged further functional parts, such. Ex. Sealing bush 45 , Thrust washer 46 and thrust bearing limiting disc 47 between impeller hub 22 and wave shoulder 34 clamped
• 2.) The thread insert 27 is only after pushing the compressor impeller 20 on the external thread 38 the compressor side shaft end 32 screwed and tightened with a corresponding torque, causing the compressor impeller 20 together with the other functional components, eg. B. Sealing bush 45 , Thrust washer 46 and thrust bearing limiting disc 47 against the wave shoulder 34 be clamped. For this purpose, the threaded insert 27 Features, for example holes 28a in the threaded insert face 28 , (see 3 , left illustration), which are suitable a Festschraubmoment with a corresponding tool on the threaded insert 27 transferred to. After tightening the threaded insert 27 this is then by means of a welded joint produced in the friction stir welding process 65 in the manner described above with the compressor impeller 20 connected.

It is particularly advantageous if the connection of the compressor impeller 20 with the compressor side shaft end 32 a welded joint made in a friction stir welding process 65 in one embodiment of the turbocharger rotor 10 characterized in that the compressor impeller 20 made of a light metal material and the rotor shaft 30 made of a steel material. By using a light metal material for the compressor impeller 20 becomes the inertial mass of the compressor impeller 20 and thus the turbocharger rotor 10 reduced overall, resulting in an improved response of an exhaust gas turbocharger having such a turbocharger rotor leads. In this case, the peculiarity of the friction-stir welding process has a particularly advantageous effect, namely that different materials are virtually joined in a hot forming process and the process takes place in temperature ranges below the melting temperature of the material to be joined, resulting in unfavorable material structure changes and residual stresses are largely avoidable in the connection area.

In a further embodiment or in development of the turbocharger rotor according to the invention 10 is, as well as in the 1 shown, between the inner end face 24 the impeller hub 22 and a wave shoulder 34 the rotor shaft 30 at least one more of the functional elements sealing bushing 45 , Thrust washer 46 , Axial bearing limiting disc 47 and oil deflector 48 is arranged. In the illustration in 1 are the thrust washer 46 and the oil deflector 48 combined in one component.

In development of the aforementioned embodiment, the turbocharger rotor 10 characterized in that at least one of the further functional elements 45 . 46 . 47 . 48 by means of a positive connection or a press fit or by means of axial clamping against the shaft shoulder 34 on the rotor shaft 30 is fixed. This reliably prevents a rotation of the functional elements 45 . 46 . 47 . 48 relative to the rotor shaft 30 and bows that way Wear between rotor shaft 30 and the functional elements 45 . 46 . 47 . 48 in front.

This in 4 Simplified friction stir-welding process is in itself already for example from EP 0 615 480 B1 known as "friction-butt-welding" or "butt-welding" and makes it possible to connect a variety of different workpieces by means of a "non-consumable" probe. The representation in 4 should illustrate the process. This will be the probe tip 61 a largely unconsumable friction stir welding probe 60 with a probe contact force F in the by a blunt bump 64 formed gap between the materials to be joined with the friction-stir welding probe 60 at a certain speed ω around its own probe longitudinal axis 62 turns to generate frictional heat. The probe tip 61 is completely submerged in the gap until the friction stir welding probe 60 with its probe face 63 rests on the workpiece surface. Upon sufficient heating, a layer of plasticized material is formed around the probe, which is largely composed of the two materials to be joined, such that upon slow traversing the rotating friction stir weld probe 60 a probe feed path S, along the connecting line or the blunt impact 64 and perpendicular to the probe longitudinal axis 62 the friction stir welding probe 60 , the plastified material is "stirred" along the connecting line with each other. During the cooling of the plasticized material, with respect to the probe feed path S behind the probe tip 61 , the plasticized material forms a welding bond 65 along the dull push 64 and thus connects the components in the desired manner with each other. The cross-sectional area of the cohesive connection depends on the geometry of the probe tip 61 the friction stir welding probe 60 which may, for example, have a conical shape with a rounded tip.

The advantage of this method is mainly that different materials are virtually connected in a hot forming process, with no special seam preparation is required and no additional materials are needed. Furthermore, the process is carried out in temperature ranges below the melting temperature of the material to be joined, whereby unfavorable material structure changes and residual stresses in the connection region are largely avoidable.

5 schematically shows an exhaust gas turbocharger 70 in section illustration of an exhaust gas turbine 71 , a compressor 72 and a bearing housing 73 includes. The exhaust gas turbine is equipped with a wastegate valve 75 equipped and the exhaust mass flow AM is indicated by arrows. The compressor has a thrust recirculation valve 76 on and the fresh air mass flow FM is also indicated by arrows. The so-called turbocharger rotor 10 the exhaust gas turbocharger 70 consists essentially of the turbine wheel 50 , the compressor impeller 20 as well as the rotor shaft 30 , The turbocharger rotor 10 rotates during operation around the rotor axis of rotation 11 the rotor shaft 30 , which is represented by the drawn center line. The turbocharger rotor 10 is with his runner shaft 30 by means of two radial bearings 35 and a thrust bearing (not shown) stored.

The non-rotating connection between the compressor-side shaft end 32 and the compressor impeller 20 has a welded connection made in a friction-stir welding method, such as one of the methods disclosed in U.S. Pat 2 or 3 illustrated embodiments of the detail Z.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102009060056 A1 [0008]
• DE 102013213023 [0008]
• US 4705463 [0009]
• EP 0615480 B1 [0036]

Claims (7)

Turbocharger rotor ( 10 ), for an exhaust gas turbine ( 71 ) and a fresh air compressor ( 72 ) having exhaust gas turbocharger ( 70 ), the at least one rotor shaft ( 30 ) with a turbine-side shaft end ( 31 ) and a compressor-side shaft end ( 32 ), one with the turbine end ( 31 ) rotatably connected turbine runner ( 50 ) and one with the compressor-side shaft end ( 32 ) rotatably connected compressor impeller ( 20 ), characterized in that the rotationally fixed connection of the compressor impeller ( 20 ) with the compressor-side shaft end ( 32 ) a welded connection produced in a friction-stir welding method ( 65 ) having. Turbocharger rotor ( 10 ) according to claim 1, characterized in that the compressor impeller ( 20 ) an impeller hub ( 22 ) with a centrally arranged through-bore ( 23 ), a turbine runner ( 50 ) facing inner end face ( 24 ) and a turbine runner ( 50 ) facing away from the outer end face ( 25 ) and that the compressor-side shaft end ( 32 ) a compressor-side shaft end face ( 33 ) and the inner end face ( 24 ) of the impeller hub ( 22 ) so far into the through hole ( 23 ) of the impeller hub ( 22 ) is inserted, that the compressor-side shaft end face ( 33 ) with the outer end face ( 25 ) of the impeller hub ( 22 ) lies in a plane and an annular gap ( 26 ) between the compressor-side shaft end ( 32 ) and the through hole ( 23 ), wherein the welded connection produced in the friction stir welding method (US Pat. 65 ) as a continuous continuous connecting seam or as individual mutually separate connecting seam sections in the region and along the annular gap ( 26 ) is trained. Turbocharger rotor ( 10 ) according to claim 1, characterized in that the compressor-side shaft end ( 32 ) of the rotor shaft ( 30 ) an external thread ( 38 ) with self-locking thread pitch and that the compressor impeller ( 20 ) an impeller hub ( 22 ) with a centrally arranged through-bore ( 23 ), a turbine runner ( 50 ) facing inner end face ( 24 ) and a turbine runner ( 50 ) facing away from the outer end face ( 25 ), wherein from the outer end face ( 25 ) ago a threaded insert ( 27 ) with an external thread ( 38 ) of the rotor shaft ( 30 ) corresponding internal thread concentric to the through hole ( 23 ) in a receiving recess ( 29 ) of the impeller hub ( 22 ), the rotor shaft ( 30 ) from the inner end face ( 24 ) of the impeller hub ( 22 ) into the through hole ( 23 ) and with the threaded insert ( 27 ) is in screw connection, wherein the compressor impeller ( 20 ) by means of the screw connection directly or indirectly against a shaft shoulder ( 34 ) of the rotor shaft ( 30 ) is rotationally clamped, wherein a threaded insert face ( 28 ) with the outer end face ( 25 ) of the impeller hub ( 22 ) lies in a plane and an annular gap ( 26 ) between an outer shell of the threaded insert ( 27 ) and the receiving recess ( 29 ) is formed and wherein, for the rotationally fixed connection of the impeller hub ( 22 ) with the threaded insert ( 27 ), the welded connection produced in the friction-stir welding method ( 65 ) as a continuous continuous connecting seam or as individual mutually separate connecting seam sections in the region and along the annular gap ( 26 ) is trained. Turbocharger rotor ( 10 ) according to claim 1 or 2, characterized in that the compressor impeller ( 20 ) made of a light metal material and the rotor shaft ( 30 ) consists of a steel material. Turbocharger rotor ( 10 ) according to one of claims 1 to 4, characterized in that between the inner end face ( 24 ) of the impeller hub ( 22 ) and a wave shoulder ( 34 ) of the rotor shaft ( 30 ) at least one further of the functional elements sealing bushing ( 45 ), Axial bearing washer ( 46 ), Thrust bearing boundary plate ( 47 ) and oil deflector ( 48 ) is arranged. Turbocharger rotor ( 10 ) according to claim 5, characterized in that at least one of the further functional elements ( 45 . 46 . 47 . 48 ) by means of a positive connection or an interference fit or by means of axial clamping against the shaft shoulder ( 34 ) on the rotor shaft ( 30 ) is fixed. Exhaust gas turbocharger ( 70 ) for an internal combustion engine of a motor vehicle with an exhaust gas turbine ( 71 ) a fresh air compressor ( 72 ) and an interposed bearing housing ( 73 ), characterized in that it comprises a turbocharger rotor ( 10 ) according to one of claims 1 to 6.

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