DE102018221134A1 - Rotor for an electric drive machine for driving a compressor, a turbine or a supercharger shaft of an exhaust gas turbocharger, electric drive machine with such a rotor and method for producing such a rotor - Google Patents

Abstract

The invention relates to a rotor for an electric drive machine (1) for driving a compressor (3), a turbine (4) or a supercharger shaft (5) of an exhaust gas turbocharger (2), with a rotor (100) around an axis of rotation (A) Rotor body (101), a receptacle (190) for at least one permanent magnet (130) being formed on the rotor body (101), at least one permanent magnet (130) being arranged in the receptacle (190) of the rotor body (101), the Rotor body (101) can be fastened to a supercharger shaft (5) of the exhaust gas turbocharger (2). It is proposed that the rotor body (101) have at least one connection element (110) and a sleeve (120) produced separately from the connection element (110), the sleeve being connected to the connection element (110) by means of a welded connection (204). Furthermore, an electric drive machine with such a rotor and method for producing such a rotor is presented.

Description

State of the art

Various electrical drive machines for an exhaust gas turbocharger are known from the prior art. For example, the DE 10 2017 207 532 A1 an exhaust gas turbocharger with an electric drive machine. Exhaust gas turbochargers of this type are used in particular in motor vehicle construction to increase the air filling in cylinders of an internal combustion engine in order to increase the performance of the internal combustion engine. An exhaust gas turbocharger is provided with an electric drive machine in order to drive the supercharger shaft of the exhaust gas turbocharger, on which a compressor wheel and a turbine wheel are arranged. By means of the electric drive machine, fresh air drawn in independently of an exhaust gas flow of the internal combustion engine can be compressed and supplied to the internal combustion engine with increased boost pressure. In this way, for example, the otherwise delayed build-up of boost pressure can be significantly accelerated.

Such an electric drive machine usually has a stator with a multi-phase drive winding for generating a drive magnetic field and a rotor. The rotor has at least one permanent magnet and is arranged in a rotationally fixed manner on the shaft of the exhaust gas turbocharger. The realization of the electromotive support by an electric drive machine integrated in the compressor or the turbine has the advantage that the motor support can be arranged in the exhaust gas turbocharger in a particularly space-saving manner. By energizing the phases of the drive winding by means of a power electronics provided for this purpose, a rotating drive magnetic field is generated, by means of which the rotor, which is rotatably supported by the charger shaft, is driven with a predeterminable torque. The permanent magnet interacts with the rotating magnetic field. With the from the DE 10 2017 207 532 A1 In known electric drive machines, the rotor has a rotor body which is formed concentrically about an axis of rotation of the rotor, a receptacle for at least one permanent magnet being formed on the rotor body, at least one permanent magnet being arranged in the receptacle of the rotor body. The one from the DE 10 2017 207 532 A1 Known electric drive machine uses an advantageous structure in which the only flow path of the medium is formed through the stator of the media splitting machine.

Furthermore, from the WO 2008/141710 A1 Embodiments of an electric drive machine for driving a compressor of an exhaust gas turbocharger are known, in which the rotor body of a rotor of the electric drive machine can be fastened to a supercharger shaft of the exhaust gas turbocharger by means of various fastening means.

Disclosure of the invention

The rotor presented here for an electric drive machine for driving a compressor, a turbine or a supercharger shaft of an exhaust gas turbocharger has a rotor body formed about an axis of rotation of the rotor, a receptacle for at least one permanent magnet being formed on the rotor body, at least one permanent magnet in the receptacle of the rotor body is arranged, the rotor body being attachable to a supercharger shaft of the exhaust gas turbocharger. It is proposed that the rotor body have at least one connection element and a sleeve produced separately from the connection element, the sleeve being connected to the connection element by means of a welded connection.

Furthermore, the invention relates to an exhaust gas turbocharger with an electric drive machine for driving a compressor, a turbine or a supercharger shaft of the exhaust gas turbocharger, which has such a rotor.

• - Bereitstellen eines konzentrisch zu einer Drehachse ausgebildeten Anschlusselementes,
• - Bereitstellen einer zylindermantelförmigen Hülse mit einem ersten Ende und einem davon abgewandten zweiten Ende und mit einer äußeren Mantelfläche und einer Innenwand,
• - Bereitstellen einer kreisrunden Stützscheibe und einer weiteren kreisrunden Stützscheibe,
• - Bereitstellen eines Rohlings für den späteren Permanentmagneten,
• - Aufbringen der kreisrunden Stützscheibe und der weiteren kreisrunden Stützscheibe auf voneinander angewandte Stirnseiten des Rohlings, so dass eine um eine Mittelachse herum zylindrisch ausgebildete Baugruppe aus dem Rohling und den darauf aufgebrachten Stützscheiben erhalten wird,
• - Aufbringung der Hülse auf die vorstehend genannte Baugruppe, wobei die Innenwand der Hülse kraftschlüssig mit der Baugruppe verbunden wird,
• - Aufsetzen der Hülse mit der darin enthaltenen Baugruppe auf das Anschlusselement derart, dass eine Mittelachse der Baugruppe und die Drehachse des Anschlusselementes konzentrisch zueinander ausgerichtet sind,
• - Verschweißen der Hülse mit dem Anschlusselement entlang einer umlaufenden Schweißverbindung und
• - Magnetisieren des Rohlings zum Erhalt eines Permanentmagneten.

The invention further relates to a method for producing a rotor for an electric drive machine for driving a compressor, a turbine or a supercharger shaft of an exhaust gas turbocharger according to one of the preceding claims, comprising the following steps:

• Provision of a connection element which is concentric with an axis of rotation,
• Provision of a cylindrical jacket-shaped sleeve with a first end and a second end facing away from it and with an outer jacket surface and an inner wall,
• Providing a circular support disc and a further circular support disc,
• Provision of a blank for the later permanent magnet,
• Applying the circular support disk and the further circular support disk to the front sides of the blank that are facing each other, so that an assembly of cylindrical shape around a central axis is obtained from the blank and the support disks applied thereon,
• - Application of the sleeve to the assembly mentioned above, the inner wall of the sleeve being non-positively connected to the assembly,
• - Placing the sleeve with the assembly contained therein on the connection element in such a way that a central axis of the assembly and the axis of rotation of the connection element are aligned concentrically to one another,
• - Welding the sleeve to the connecting element along a circumferential weld connection and
• - Magnetize the blank to obtain a permanent magnet.

Advantages of the invention

A technical connection in the development of an electric drive machine of an electrically assisted exhaust gas turbocharger can be seen in the relationship between the torque of the electric drive machine and the mass moment of inertia of the rotor group of the turbocharger. The mass of the rotor of the electric drive machine mounted on the charger shaft leads to an additional load on the charger shaft and the associated bearing bushes in comparison to an exhaust gas turbocharger without an electric drive machine. The high speed level of the exhaust gas turbocharger presents a particular difficulty. It is important that the overall structure is mechanically and electrically stable even at high speeds. The additional mass of the rotor increases the mass of the entire rotor arrangement mounted on the loader shaft. This means not only an increase in the moment of inertia of the loader, but also a shift in the center of gravity almost in the center of one of the bearing bushes of the loader shaft. This effect can have a negative impact on the resulting bearing load, since the surface pressure in the two running surfaces of the bearing bushes can vary greatly.

The rotor according to the invention advantageously makes it possible to produce an electric drive machine with the smallest possible imbalance of the rotor arrangement, consisting of the supercharger shaft, compressor or turbine wheel and rotor. In addition, the permanent magnet of the rotor can be protected against harmful environmental influences, in particular exhaust gases and condensates, and thus corrosion can be avoided or at least reduced.

The rotor presented here is mechanically robust and advantageously makes it possible to mount the rotor on a supercharger shaft of an exhaust gas turbocharger in a simple manner and to screw it onto the supercharger shaft, for example, with a low load on the components.

One difficulty is that, on the one hand, fastening means have to be formed on the rotor body, on the other hand, a sufficiently robust and secure fastening for the permanent magnet in the rotor body must also be represented, the overall structure of the rotor body should minimize the risk of imbalance on the supercharger shaft.

According to the invention, this is achieved in that the rotor body has at least one connection element and a sleeve which is produced separately from the connection element, the sleeve being connected to the connection element by means of a welded connection. The separate production of the connecting element and the sleeve advantageously makes it possible to improve the arrangement of the permanent magnet on the rotor and the attachment of the rotor body to a supercharger shaft, with greater degrees of freedom in the design and the material selection of the connecting element and the sleeve.

The sleeve represents a bandage or reinforcement for the at least one permanent magnet, in order to effectively protect it even under high centrifugal forces and harsh temperature influences on the exhaust gas turbocharger. The sleeve should not affect the magnetic properties of the permanent magnet and the stator. The material of the sleeve should therefore be non-magnetic. In addition, the sleeve can advantageously have a small wall thickness, since this also has an influence on the magnetic flux. In addition, corrosion of the at least one permanent magnet by the sleeve can advantageously be avoided. The at least one permanent magnet (for example a magnet made of SmCo, Sm2Co17 or NdFeB) can advantageously be pressed into the sleeve. As a semi-finished tube, the sleeve can be made of a non-magnetic material (e.g. Inconel®718, nickel alloys, titanium or fine-grain hard metal).

The connecting element can be inexpensively manufactured as a turned part made of, for example, stainless steel (in particular stainless steel X5CrNiCuNb16-4). The connection element has means for fastening the rotor body to the loader shaft, which can be done, for example, by screwable fastening means.

The sleeve is welded onto the connecting element in a simple manner, which is particularly simple and reliable to manufacture.

Advantageous refinements and developments of the invention are made possible by the features contained in the dependent claims.

In a preferred embodiment, the connection element can be an outer jacket, a have the inside and at least one permanent magnet facing away from the inside, the connecting element has a platform on the inside, the platform having a circumferential surface parallel to the axis of rotation, the diameter of the platform being smaller than that in a cross-sectional plane perpendicular to the axis of rotation Outside diameter of the outer jacket, whereby a shoulder is formed on the connection element. The sleeve has a first end and a second end facing away from it in the direction of the axis of rotation. In order to be able to join the sleeve with the connection element, the sleeve can be placed with the second end on the platform, an inner wall of the sleeve being guided over the circumferential surface and an end face of the sleeve arranged on the second end of the sleeve resting against the shoulder. This advantageously enables easier alignment of the sleeve with the magnet assembly relative to the connection element during assembly, since the central axis of the magnet assembly and thus the center of gravity of the magnet assembly should coincide with the axis of rotation of the connection element in order to avoid imbalance of the rotor body.

The sleeve can advantageously have an outer lateral surface which is aligned with the outer jacket of the connecting element in the direction of the axis of rotation. In this way, a step or edge in the transition area between the sleeve and the connecting element is avoided and a smooth surface is made possible, which makes it more difficult for corrosive exhaust gases or aggressive substances to penetrate into the rotor body.

A support disk can be arranged in the rotor body between the connection element and the at least one permanent magnet. Furthermore, the rotor body can have a further support disk on a side of the permanent magnet facing away from the support disk. The at least one permanent magnet has the task of driving the exhaust gas turbocharger by means of a magnetic field which is induced by the stator. The press fit between the permanent magnet and the sleeve must therefore be dimensioned sufficiently to be able to transmit the required torque. For this purpose, it is advantageous if a support disk is provided between the inside of the connection element and the at least one permanent magnet. Furthermore, the rotor body can have a further support disk on a side of the permanent magnet facing away from the support disk. The support disks can be made of the same material as the sleeve. With a press fit of the permanent magnet in the sleeve, higher joint pressures and tangential stresses could occur without the support disks and the connecting element at the outlet of the sleeve. The support disks advantageously protect the permanent magnet against high mechanical loads during the pressing in the sleeve, in particular at its edges. During the manufacture of the rotor, the sleeve can be pressed on via the magnet unit consisting of support disks and permanent magnet. The sleeve with the assembled magnetic assembly can then be welded radially to the connection element. The permanent magnet is supported axially via the support disks. The further support disk on the end face of the rotor body can be welded axially or radially to the sleeve after mounting on the connection element.

The connection element can have a cylindrical bore concentric to the axis of rotation, which serves to introduce the loader shaft. The bore may further include a first portion and at least a second portion, the first portion having an inner diameter, the inner diameter being formed to form an interference fit between the charger shaft and the inner wall of the bore, and the second portion being internally threaded or forms a receptacle for a threaded bushing arranged in the rotor body. The first section can advantageously be formed with a centering diameter, so that, for example, the rotor body can be centered on the charger shaft independently of the screw connection by pressing the inner wall of the bore onto the outside diameter of the charger shaft.

During manufacture, a circular support disk and a further circular support disk can first be applied, for example, to end faces of the blank for the permanent magnet facing away from one another, so that an assembly which is cylindrical around a central axis and is made up of the blank and the support disks attached to it is produced. The sleeve can then be applied to the above-mentioned assembly, the inner wall of the sleeve being applied to the assembly with a defined force, so that the inner wall is non-positively connected to the assembly, which can be done by pressing and / or heating the sleeve. The sleeve with the assembly contained therein forms a magnetic assembly which can be placed on the connection element, a central axis of the assembly and the axis of rotation of the connection element being aligned concentrically to one another in order to avoid imbalance of the rotor body. The sleeve is then welded all around to the connection element, so that a firm bond is created. Finally, the blank can preferably be magnetized as one of the last steps, but this can also be done beforehand.

The alignment and connection of the magnet assembly and the connection element can advantageously be improved if the connection element has an outer jacket, an inside facing the at least one permanent magnet and an outside facing away from it, the connection element having a platform on the inside, the platform parallel to the axis of rotation has a circumferential surface, the diameter of the platform in a cross-sectional plane perpendicular to the axis of rotation being smaller than the outer diameter of the outer jacket, as a result of which a shoulder is formed on the connecting element. During the assembly of the magnetic assembly, the sleeve with a circumferential collar made thereon can be pushed onto the pedestal, an inner wall of the sleeve being guided over the circumferential surface of the pedestal in the region of the collar until an end face of the sleeve arranged at the second end of the sleeve fits the shoulder. In a simple manner, the sleeve can be welded all around the shoulder in the region of the shoulder, the welding device preferably being oriented perpendicular to the axis of rotation.

To further stabilize the rotor, a further welding process can be carried out between the further support disk and the first end of the sleeve, in which the outer edge of the further support disk is welded all round to the inner wall of the sleeve, the welding device preferably being aligned parallel to the axis of rotation.

Figure list

• 1 eine schematische Schnittansicht eines Abgasturboladers mit einer elektrischen Antriebsmaschine gemäß einer Ausführungsform der Erfindung,
• 2a einen Rotor der elektrischen Antriebsmaschine mit einer Gewindebuchse in einer gegenüber 1 leicht veränderten zweiten Ausführungsform,
• 2b einen Rotor der elektrischen Antriebsmaschine in einer dritten Ausführungsform
• 3 eine perspektivische Ansicht eines Rotors gemäß einer vierten Ausführungsform,
• 4 eine perspektivische Ansicht eines Rotors gemäß einer fünften Ausführungsform,
• 5 eine perspektivische Ansicht eines Spannwerkzeuges,
• 6a bis 6c Querschnitte durch eine Magnetbaugruppe, während der Herstellung,
• 7a bis 7e weitere Querschnitte durch die Magnetbraugruppe und den Rotorkörper während der Herstellung des Rotors.

Show it:

• 1 2 shows a schematic sectional view of an exhaust gas turbocharger with an electric drive machine according to an embodiment of the invention,
• 2a a rotor of the electric drive machine with a threaded bush in one opposite 1 slightly modified second embodiment,
• 2 B a rotor of the electric drive machine in a third embodiment
• 3rd 2 shows a perspective view of a rotor according to a fourth embodiment,
• 4th 2 shows a perspective view of a rotor according to a fifth embodiment,
• 5 a perspective view of a clamping tool,
• 6a to 6c Cross sections through a magnetic assembly, during manufacture,
• 7a to 7e further cross sections through the magnetic brewing group and the rotor body during the manufacture of the rotor.

Embodiments of the invention

1 shows a longitudinal section through an exhaust gas turbocharger 2nd an internal combustion engine with an electric drive machine 1 . The exhaust gas turbocharger comprises a housing which is shown only schematically here 6 , which in particular can also be made in several parts with a bearing housing, a compressor housing and turbine housing, not shown. The exhaust gas turbocharger comprises a compressor 3rd and a turbine 4th . In 1 is a compressor wheel 13 of the compressor 3rd and a turbine wheel 14 the turbine 4th shown schematically. The compressor wheel 13 and the turbine rim 14 can on a common supercharger shaft 5 be rotatably arranged. The supercharger shaft 5 is in bushings 15 in the housing 6 of the exhaust gas turbocharger 2nd about an axis of rotation A rotatably mounted.

The turbine 4th can be understood as a rotating fluid machine, which is set up to convert a drop in an internal energy of a flowing fluid into a mechanical power, which it generates via the supercharger shaft 5 delivers. Part of an internal energy, in particular comprising kinetic energy, positional energy and / or pressure energy, which can be transferred to rotor blades of the turbine, can be extracted from a fluid flow by a laminar flow around turbine blades which is as free of eddies as possible. The supercharger shaft can then pass over part of the internal energy 5 can be rotated and a usable power can be coupled to a work machine, such as a compressor 3rd be delivered. The turbine 4th may be configured to be driven by exhaust gases from an internal combustion engine.

The compressor 3rd is set up to increase a pressure and / or a density of a flowing gas and in particular flowing air. The compressor can in particular be a radial compressor. The radial compressor can be used to add energy to a flowing fluid by a rotating rotor according to the laws of fluid mechanics. The radial compressor can be designed such that the gas essentially axially into a compressor wheel 13 flows and then radially, ie is deflected outwards.

The electric prime mover 1 is set up to generate a rotational movement of a rotor by applying an electrical current. All or part of the electric drive machine is designed as an electric motor. In particular, the electric drive machine is used to the compressor, the turbine or the supercharger shaft 5 of the exhaust gas turbocharger 2nd to drive. The electric prime mover 1 can in particular like that in the DE 10 2017 207 532 A1 described electric drive machine are installed in an exhaust gas turbocharger, the electric drive machine presented here one opposite DE 10 2017 207 532 A1 has novel and easy to manufacture structure of the rotor.

The electric drive machine has a rotor 100 and a stator 20th on. The stator 20th forms a fixed component of the electric drive machine 1 and has, for example, an annular stator yoke and stator teeth protruding radially inward from the stator yoke, which are spaced apart from one another in the circumferential direction and are evenly distributed. The stator teeth are usually of a multi-phase drive winding 21st wrapped, by energizing the phases of the drive winding 21st the rotating drive magnetic field is generated by means of a power electronics provided for this purpose, through which the through the charger shaft 5 rotatably mounted rotor 100 is driven with a predeterminable torque. The rotor 100 has a rotor body 101 which is set up to have at least one permanent magnet 130 to record. The rotor body 100 can also do more than one permanent magnet 130 record, tape. The rotor 100 works with the rotating magnetic field of the stator 20th together. The rotor body 101 of the rotor 100 is a body of revolution around an axis of rotation A formed around, in particular concentric about the axis of rotation A educated. The axis of rotation is preferably A of the rotor body 101 identical to the axis of rotation of the loader shaft 5 .

As best with the help of 2a can be seen is on the rotor body 101 a recording 190 for the at least one permanent magnet 130 educated. The rotor body 101 can in the embodiment of 2a by means of a threaded bush 140 on an external thread 51 the supercharger shaft 5 be screwed on in such a way that a result of the screw connection and in the direction of the axis of rotation A acting axial clamping force the rotor body 101 directly or indirectly with the compressor wheel in between 13 and possibly other components, for example an axial bearing of the loader shaft, against a stop 52 on the loader shaft 5 pressed. The supercharger shaft 5 can be formed in one piece as shown. The supercharger shaft 5 But can also be formed in several parts and have a rotor shaft connected to the rotor, which can be rotatably coupled to the loader shaft, for example via a coupling device. The supercharger shaft 5 has a cylindrical outer jacket which on its the rotor 100 facing end with the external thread 51 is provided.

First, the construction of the rotor 100 based on 2a described in more detail. The rotor 100 is preferably constructed in several parts and has at least the rotor body 101 who have favourited Threaded Bushing 140 and the at least one permanent magnet 130 on. As shown, the permanent magnet has at least one north and south pole and can be, for example, a magnet made of SmCo, Sm2Co17 or NdFeB. The rotor body 101 is made up of several parts. In particular, the rotor body has 101 one the permanent magnet 130 surrounding sleeve 120 on, with the sleeve 120 on a connection element 110 of the rotor body 101 is arranged. The term “sleeve” basically describes any elongated hollow body. The hollow body can have a length and a diameter. The length can be greater than the diameter, for example by a factor of 1.5, preferably by a factor of 2, particularly preferably by a factor of 3. The diameter can in particular have a round shape. However, other configurations are also conceivable in principle. The sleeve can therefore also be referred to as a "pipe". The cylindrical inner wall 123 the sleeve 120 forms a recording 190 for the permanent magnet 130 . The permanent magnet 130 can in the sleeve 120 be used non-positively, as will be explained below. The sleeve 120 can in particular be made of a non-magnetic material. As a result, an influence of the sleeve on magnetic properties of the permanent magnet and / or of the stator can be avoided or at least further reduced. The sleeve 120 can also be set up to protect the permanent magnet, in particular radially, from corrosion. At higher speeds, the permanent magnet can be pressed and / or bandaged so that it is not damaged by the centrifugal forces. A higher compression can lead to an increase in the tension in the sleeve, which in turn can be reduced by increasing the wall thickness. For example, the sleeve can be formed from the material NiCr19Fe19Nb5Mo3. The sleeve can have a wall thickness of 0.1 mm to 5 mm, in particular 0.5 mm to 2 mm, preferably 0.8 mm to 1.5 mm and particularly preferably 1.025 mm.

The connection element 110 can have a cylindrical outer jacket 111 , one of the at least one permanent magnet 130 facing inside 113 and an outside that repels it 112 exhibit. The connection element 110 can for example be made as a simple turned part made of stainless steel. On the inside 113 of the connection element 110 is in the embodiment of 2a concentric to the axis of rotation A a Lowering 182 trained that another shot 180 for the threaded beech 140 trains. Between the inside 113 of the connection element 110 and the at least one permanent magnet 130 is a the threaded bush 140 on the inside 113 of the connection element 110 covering support disc 160 arranged. On the of the threaded bush 140 opposite side of the permanent magnet 130 points the rotor body 101 another support disc 170 , which is also referred to below as the outer support disk. Furthermore, the connection element 110 concentric to the axis of rotation A a cylindrical bore 150 on. The inside diameter D1 the cylindrical bore 150 is smaller than the inside diameter D2 the further recording 180 , creating a level 114 is formed, which is an edition 115 for the threaded bush 140 forms.

The threaded bush 140 can preferably from the inside 113 in the further admission 180 be used. As continues in 2a is recognizable, the threaded bushing 140 an internal thread 142 and an outer jacket 141 on. The outer jacket 141 the threaded bushing and the inner wall 181 the further recording 180 are designed such that the outer jacket 141 when rotating around the axis of rotation A relative to the rotor body 101 on an inner wall 181 the further recording 180 comes to the plant. The outer jacket can do this 141 have a projection, not shown, when rotating about the axis of rotation A relative to the rotor body 101 on a step of the inner wall, also not shown 181 comes to the plant. The outer jacket can be an example 141 the threaded bush 140 be formed by a hexagon. The inner wall can correspond to this 181 of the connection element 110 also be formed as a complementary hexagon. In addition, the inside diameter D2 the further recording 180 somewhat larger than the outer diameter of the threaded bush 140 . This ensures that perpendicular to the axis of rotation A between the threaded bush 140 and the rotor body 101 a game in the radial direction S1 consists, as in 2nd is recognizable. The threaded bush 140 is with play in the further admission 180 inserted, but can be rotated around the axis A nevertheless for contact with the inner wall 181 the further recording 180 reach. Alternatively, it is also possible to use the outer jacket 141 the threaded bushing with a harmonic triangular profile or P3G profile. The harmonious polygon profile with a continuous P3 shape curve results in a "constant thickness" in all angular positions and thus a high-quality profile for torque transmission. In the embodiment in 2a can be between the inner support disc 160 and threaded sleeve 140 another game S2 consist. This is the threaded sleeve 140 in the axial direction (i.e. in the direction of the axis of rotation A ) and because of the game S1 Movable in the radial direction (perpendicular to the axis of rotation) and more or less as a “floating” socket in the further holder 180 movable.

An alternative embodiment of the rotor 100 is in 2 B shown. In this embodiment, the rotor body has 101 no threaded bush. The connection element in turn points concentrically to the axis of rotation A a cylindrical bore 150 having. The hole 150 has a first section and at least a second section, the first section being similar to that in FIG 2a an inner diameter D1 on, with the inside diameter D1 to form an interference fit between the supercharger shaft 5 and the inner wall 151 the hole 150 is trained. In contrast to 2a but is now a second section of the hole 150 with an internal thread 143 is provided, in which the external thread 51 the supercharger shaft 5 can be screwed in. In this embodiment, the supercharger shaft 5 screwed directly to the connection element.

Before going on to further details of the attachment of the rotor 100 on the loader shaft 5 is a method of manufacturing the rotor 100 to 2a and 2 B and the further construction of the rotor 100 based on 6a to 6c and 7a to 7e explained. In these figures, only the rotor design is shown 2a shown. However, the manufacturing process is for the in 2 B shown rotor feasible analog.

In a first step to manufacture the rotor 100 is, for example, in 6a a not yet magnetized blank 130a for the later permanent magnet 130 provided with cylindrical dimensions. The face of the blank 130a are in the 6a abraded by the dashed line axial end faces. Then a support disc 160 and another support disc 170 on the end faces of the blank facing away from one another 130a applied, which can be done for example by gluing, as in 6b is shown. The support washers 160 , 170 can be produced as stamped parts from non-magnetic material and then subjected to a heat treatment and a grinding process.

As in 6c the assembly can be shown 400 consisting of the blank 130 and the glued on support discs 160 , 170 undergo a further grinding process on the surface. Then the assembly 400 , as in 7a shown in the sleeve 120 be introduced. This can be done, for example, by pressing. In addition or as an alternative, heat treatment of the sleeve can also be carried out 120 respectively. It is also possible to heat the sleeve and the assembly 400 insert into the sleeve and then cool the entire assembly. The pressing force or the frictional connection between the sleeve and the permanent magnet must be large enough to be able to transmit the required torques. The support washers 160 , 170 protect in particular the edges of the blank 130a before damage when pressing on the sleeve 120 .

The sleeve 120 can be manufactured as an axial turned part and on the inner wall 123 be subjected to a grinding process. The sleeve 120 preferably has a circumferential collar 121 on, as an axial extension in the direction of the axis of rotation A over the support disc 160 cantilevered from the assembly.

As in 7a is recognizable, the blank fills 130a the entire space between the inside of the sleeve 120 and the support washers 160 , 170 out.

As in 7b shown, the assembled magnetic assembly can 7a on the connection element described above 110 to be ordered. First, the threaded bush 140 in the further admission 180 of the connection element 110 inserted and then the magnet assembly with the collar 121 on a pedestal 116 on the inside 113 of the connecting element pushed or pressed.

As in 2a and 2 B The connection element shows better 110 an outer jacket 111 , an inside facing the at least one permanent magnet 113 and an outside that repels it 112 on, with the connector on the inside 113 the podium 116 having. The podium 116 has parallel to the axis of rotation A a peripheral surface 118 , the diameter of the pedestal 116 in the cross-sectional plane perpendicular to the axis of rotation A is smaller than the outer diameter of the outer jacket 111 , whereby on the connection element 110 one shoulder 119 is formed. The sleeve 120 has in the direction of the axis of rotation A or seen in the direction of the central axis M a first end 129 and a second end turned away from it 128 . The sleeve 120 will end with the second 128 on the pedestal ( 116 ) is placed, the inner wall 123 the sleeve over the peripheral surface 118 is guided until one at the second end 128 the end face of the sleeve 125 the sleeve 120 on the shoulder 119 is present. By sliding it over the platform 116 can be achieved in a simple manner that the central axis M of the sleeve with the assembly contained therein 400 with the axis of rotation A of the connection element 110 coincides. The sleeve preferably has 120 an outer surface 122 on that with the outer jacket 111 of the connection element 110 in the direction of the axis of rotation A flees.

Then, as in 7c shown the all-round collar 121 in the radial direction with the connecting element 110 at the position 202 are welded all round, the welding device preferably perpendicular to the axis of rotation ( A ) is aligned and a circumferential weld connection 204 arises. A weld 203 arises between the face 125 the sleeve 120 and the shoulder 119 of the connection element 110 .

In addition, in the axial or (not shown) radial direction, a further welding process can take place between the peripheral edge of the further support disk 170 and the sleeve 120 at the position 201 occur.

In a further step, the in 7d is indicated, the almost finished rotor 100 in levels at the positions W1 and W2 from 7d be balanced.

Finally, as in 7e is shown, the blank 130a be magnetized and thereby in the permanent magnet 130 be changed.

3rd shows a perspective view of a rotor body 101 according to a further embodiment. To facilitate the assembly of the rotor 100 on the loader shaft 5 can the rotor body 101 have a shape that allows the attachment of an assembly tool. As in 3rd shown, the rotor body 101 on the outer jacket 111 of the connection element 110 a key area 117 for attaching a tool wrench. At the in 3rd The embodiment shown is the key surface 117 double-shaped.

4th shows a perspective view of a rotor body 101 according to a further embodiment. Only the differences from the exemplary embodiment are shown below 3rd and the same components are provided with the same reference numerals. As in 4th shown, the key surface 117 be hexagonal. Alternatively, the key surface 117 be square or similar.

5 shows a perspective view of a collet 300 . The collet is a clamping device to clamp workpieces or tools quickly and force-fit with high accuracy. It consists of an externally conical, radially slotted sleeve with a round, sometimes square or hexagonal hole of a defined size. A collet has a collet holder with one to the collet matching inner cone. Clamping is done by tightening a union nut with which the collet is pressed into the inner cone of the collet holder. Due to the slot in the collet, the bore is evenly compressed inside, which means that the workpiece or tool is held firmly. Collets clamp bare or machined parts quickly, firmly and precisely in the center. The outer jacket 111 of the connection element 110 can have a mounting section for attaching the collet 300 exhibit. The rotor can accordingly 100 using the collet 300 on the loader shaft 5 are attached, in particular by holding the supercharger shaft in the area of the turbine wheel and / or countering.

It is also possible to use the rotor 100 in the area of the additional support disc 170 to be provided with an inner torx (not shown) in which a tool for screwing on the rotor 100 on the supercharger shaft 5 can be used.

Furthermore, it is also possible, in an embodiment not shown in the figures, the connection element without the pedestal 116 form and instead a further circumferential collar on the connection element 110 to provide the one with the face 125 the sleeve 120 is welded.

The rotor 100 can be screwed to the loader shaft in all embodiments 5 screwed on and at the same time, for example, with a cylindrical press fit to the axis of rotation A the supercharger shaft 5 be aligned. As already shown, the connection element 110 of the rotor 100 concentric to the axis of rotation A a cylindrical bore 150 on. The inside diameter D1 this cylindrical bore 150 is for forming an interference fit between the supercharger shaft 5 and the inner wall 151 the bore trained.

A "fit" is a dimensional relationship between two components that should fit together without rework. These components have the same contour at the joint, once as the inner shape and once as the outer shape. Both contours have the same nominal size. The two tolerance fields are different, within which the actual dimensions of the inner shape and outer shape that arise during production must lie.

A press fit is a dimensional relationship between two components in the form of an inner shape and an outer shape, in which the largest dimension of an inner contour of the outer shape is in any case smaller than a smallest dimension of an outer contour of the inner shape. The interference fit can also be called an interference fit. In principle, the excess should be made as small as possible due to an expected increase in torque when the rotor is mounted on the supercharger shaft. The torsional moment can generally increase the higher the compression is selected.

The supercharger shaft 5 points at their for fastening the rotor 100 provided end a first section with an external thread 51 on ( 1 ). On the one with the external thread 51 provided section closes in the direction of the axis of rotation A on the side of the external thread facing away from the rotor 51 an area where the supercharger shaft 5 a cylindrical outer jacket 53 which is provided as a press area. The cylindrical outer jacket 53 points at the in 1 illustrated embodiment in this area a diameter D3 on which is larger than the inside diameter D1 the cylindrical bore 150 is.

When fixing the rotor 100 on the loader shaft 5 , is in the embodiment according to 2a the one with the external thread 51 area through the hole 150 of the rotor body 101 pushed through and into the threaded bush 140 screwed in. At the same time, the inner wall 151 the hole 150 on the cylindrical outer jacket 53 pressed on. When screwing on the rotor 100 on the supercharger shaft 5 acts the threaded bush 140 thereby as a floating threaded bush and allowed due to the play S1 radial tolerance compensation. The threaded bush 140 has an internal thread 142 which can be an internal fine thread or an internal regular thread. The fine thread can have an advantage over a regular thread in terms of a higher self-locking. The standard thread can be a standardized thread with metric dimensions. This usually has a 62 ° flank angle. Such threads are standardized, for example, according to DIN 13-1. The standard thread can also be a UNF thread. In the context of the present invention, a “fine thread” is to be understood as a thread that has a narrower thread profile in comparison to the standard thread. To distinguish it, it is usually marked in addition to the outside diameter with the dimension of its smaller pitch.

In the embodiment of 2 B becomes the external thread 51 the supercharger shaft 5 directly into the internal thread 143 the hole 150 screwed in. In both embodiments 2a and 2 B can center the rotor relative to the axis of rotation A the supercharger shaft 5 by means of the press fit between the inner wall 151 the hole 150 and the outer jacket 53 the supercharger shaft 5 respectively. An axial clamping force is generated by means of the screw connection, as a result of which the connecting element 110 with its outside 112 against a stop surface on the compressor wheel 13 is pressed as best in 1 can be seen. The compressor wheel 13 is supported directly (or indirectly via an axial bush) on a stop 52 the supercharger shaft 5 off so the compressor wheel 13 between the stop 52 and the connecting element 110 of the rotor 100 is clamped. Thus, by means of the rotor 100 a defined axial preload force can be applied to the compressor wheel.

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included 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.

Patent literature cited

• DE 102017207532 A1 [0001, 0002, 0027]
• WO 2008/141710 A1 [0003]

Claims (13)

Rotor for an electric drive machine (1) for driving a compressor (3), a turbine (4) or a supercharger shaft (5) of an exhaust gas turbocharger (2), with a rotor body (101) formed around an axis of rotation (A) of the rotor (100) ), a receptacle (190) for at least one permanent magnet (130) being formed on the rotor body (101), at least one permanent magnet (130) being arranged in the receptacle (190) of the rotor body (101), the rotor body (101 ) can be fastened to a supercharger shaft (5) of the exhaust gas turbocharger (2), characterized in that the rotor body (101) has at least one connection element (110) and a sleeve (120) produced separately from the connection element (110), the sleeve being by means of a welded connection (204) is connected to the connection element (110). Rotor after Claim 1 characterized in that the connection element (110) has an outer jacket (111), an inside (113) facing the at least one permanent magnet and an outside (112) facing away from it, the connection element on the inside (113) having a platform (116) The platform (116) has a circumferential surface (118) parallel to the axis of rotation (A), the diameter of the platform (116) in a cross-sectional plane perpendicular to the axis of rotation (A) being smaller than the outer diameter of the outer casing (111) , whereby a shoulder (119) is formed on the connection element (110). Rotor after Claim 2 , characterized in that the sleeve (120) in the direction of the axis of rotation (A) has a first end (129) and a second end (128) facing away from it and that the sleeve (120) with the second end (128) on the platform (116) is placed, an inner wall (123) of the sleeve being guided over the circumferential surface (118) and an end face (125) of the sleeve (120) arranged on the second end (128) of the sleeve resting against the shoulder (119) . Rotor according to one of the preceding claims, characterized in that the sleeve (120) has an outer lateral surface (122) and in that the outer lateral surface (122) of the sleeve is aligned with the outer jacket (111) of the connecting element in the direction of the axis of rotation (A). Rotor according to one of the preceding claims, characterized in that a support disk (160) is arranged in the rotor body (101) between the connection element (110) and the at least one permanent magnet (130). Rotor according to one of the preceding claims, characterized in that the rotor body (101) has a further support disk (170) on a side of the permanent magnet (130) facing away from the support disk (160). Rotor according to one of the preceding claims, characterized in that the connecting element (110) has a cylindrical bore (150) concentric to the axis of rotation (A). Rotor after Claim 7 , characterized in that the bore (150) has a first section and at least a second section, the first section having an inner diameter (D1), the inner diameter (D1) for forming an interference fit between the charger shaft (5) and the inner wall (151) of the bore (150), and wherein the second section is provided with an internal thread (143) or forms a receptacle (180) for a threaded bushing (140) arranged in the rotor body (101). Electric drive machine (1) for driving a compressor (3), a turbine (4) or a supercharger shaft (5) of an exhaust gas turbocharger (2) with a rotor (100) according to one of the preceding claims. A method for producing a rotor (100) for an electric drive machine (1) for driving a compressor (3), a turbine (4) or a supercharger shaft (5) of an exhaust gas turbocharger (2) according to one of the preceding claims, the method comprising the following steps comprising: - providing a connecting element (110) which is concentric with an axis of rotation (A), - providing a cylindrical jacket-shaped sleeve (120) with a first end (129) and a second end (128) facing away from it and with an outer jacket surface (122) and an inner wall (123), - providing a circular support disc (160) and a further circular support disc (170), - providing a blank (130a) for the later permanent magnet (130), - applying the circular support disc (160) and the others circular support disc (170) on mutually facing end faces of the blank (130a), so that an assembly (400) which is cylindrical around a central axis s the blank (130) and the support disks (160, 170) mounted thereon, - application of the sleeve (120) to the above-mentioned assembly (400), the inner wall (123) of the sleeve (120) being non-positively connected to the assembly (400) is connected - placing the sleeve (120) with the assembly (400) contained therein on the connection element (110) such that a central axis (M) of the assembly (400) and the axis of rotation (A) of the connection element are concentric with each other are aligned, Welding the sleeve (120) to the connecting element along a circumferential weld connection (204), - magnetizing the blank (130a) to obtain a permanent magnet (130). Procedure according to Claim 10 characterized in that the connection element (110) has an outer jacket (111), an inside (113) facing the at least one permanent magnet and an outside (112) facing away from it, the connection element on the inside (113) having a platform (116) The platform (116) has a circumferential surface (118) parallel to the axis of rotation (A), the diameter of the platform (116) in a cross-sectional plane perpendicular to the axis of rotation (A) being smaller than the outer diameter of the outer casing (111) , whereby a shoulder (119) is formed on the connection element (110) and the sleeve (120) is arranged on the assembly (400) when the sleeve (120) is applied in such a way that the sleeve (120) at its second end (128) protrudes a little above the support disc (160), so that a circumferential collar (121) is created, and that the sleeve (120) with the circumferential collar (121) is pushed onto the platform (116), an inner wall ( 123) the Hüls e (120) is guided in the region of the collar (121) over the peripheral surface (118) until an end face (125) of the sleeve (120) arranged on the second end (128) of the sleeve (120) on the shoulder (119) is present. Procedure according to Claim 10 or 11 , characterized in that the sleeve (120) is welded circumferentially in the region of the shoulder (119) to the connecting element (110), the welding device preferably being oriented perpendicular to the axis of rotation (A). Procedure according to Claim 10 to 12 , characterized in that a further welding process is carried out between the further support disk (170) and the first end (129) of the sleeve (120), in which the outer edge of the further support disk (170) runs all the way around with the inner wall (123) of the sleeve ( 120) is welded, the welding device preferably being aligned parallel to the axis of rotation (A).

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