Bearing seat body for a rotor shaft of an electric machine, rotor shaft, rotor, electric machine and motor vehicle

Abstract

The invention relates to a bearing seat body (1), to a rotor shaft (3) having the bearing seat body (1), to a rotor, to an electric machine, and to a motor vehicle having the electric machine. The aim of the invention is to provide a particularly reliable connection option between a bearing seat of a rotor shaft and a radial bearing designed to support the rotor shaft. The bearing seat body (1) has a line channel assembly (4) comprising a line channel (5), which passes through a shaft body (2) of the bearing seat body (1) along the direction (x) of longitudinal extent thereof and the channel opening (6) of which opens at an end face (7) of the shaft body (2). Furthermore, the bearing seat body (1) has a compensating opening assembly (8) comprising a compensating opening (9) which passes through the shaft body (2) along the direction (x) of longitudinal extent, the opening orifice (10) of which opens at the end face (7) and which runs, starting from the end face (7), completely through a bearing seat longitudinal portion (15) of the shaft body (2) in which a bearing seat (11) of the bearing seat body (1) is provided.

Description

[0001] Bearing seat body for a rotor shaft of an electric machine, rotor shaft, rotor, electric machine and motor vehicle

[0002] The present invention relates to a bearing seat body for a rotor shaft of an electric machine, and to a rotor shaft comprising such a bearing seat body and a rotor shaft body fixed thereto in a rotationally fixed manner. The invention further relates to a rotor comprising such a rotor shaft. The invention also relates to an electric machine comprising such a rotor and to a motor vehicle comprising such an electric machine.

[0003] In externally excited or electrically excited synchronous machines, a field coil assembly is mounted on the rotor shaft. To generate torque with such an electric machine, electrical excitation energy must be supplied to the field coil assembly, for example, via slip rings. This necessitates routing conductor elements (such as cables, wires, etc.) through corresponding channels inside the rotor shaft. These channels are arranged, for example, so that they enter the rotor shaft via an end face, which means that the channels pass axially through a bearing seat of the rotor shaft. Consequently, the rotor shaft is weakened at the bearing seat by the channels passing through it. If an inner ring of a radial bearing is then pressed onto the (weakened) bearing seat, the rotor shaft will be deformed at this point in an undesirable way, becoming out of round.In other words, the outer surface of the rotor shaft is deformed at the bearing seat. As a result, the radial bearing does not sit perfectly round or evenly on the outer surface of the rotor shaft along the entire circumference of the inner ring. Furthermore, during operation of the electric machine—that is, when the rotor shaft is rotating—an unfavorable dynamic imbalance arises, which can lead to bearing failure and / or acoustic problems. To compensate for this geometric deviation during operation, correspondingly robust radial bearings are currently used, but these result in an unfavorably high mass for the electric machine.

[0004] Other measures known from the prior art for reducing the dynamic imbalance of an electric machine rotor are known, for example, from DE 10 2021 202 963 A1 or DE 10 2012 205 756 A1. However, these do not solve the problem of the deformed bearing seat of the respective rotor shaft.

[0005] The object of the present invention is to create a particularly reliable connection between a bearing seat of a rotor shaft and a radial bearing designed to support the rotor shaft.

[0006] This problem is solved by the subject matter of the independent claims. Further possible embodiments of the invention are disclosed in the dependent claims, the description, and the figures. Features, advantages, and possible embodiments set forth in the description for one of the subject matter of the independent claims are to be regarded, at least analogously, across categories and embodiments as features, advantages, and possible embodiments of the respective subject matter of the other independent claims, as well as of any possible combination of the subject matter of the independent claims, optionally in conjunction with one or more of the dependent claims.

[0007] According to the invention, a bearing seat body for a rotor shaft of an electric machine is proposed. In its intended installation position, the bearing seat body forms part of a rotor shaft for the electric machine, the rotor shaft itself being also an object of the invention. The rotor shaft comprises the bearing seat body and a rotor shaft body, the bearing seat body and the rotor shaft body being rotationally fixed to one another. A further object of the invention is a rotor for an electric machine comprising the rotor shaft and a field coil assembly mounted rotationally fixed to the rotor shaft body. The invention also relates to an electric machine comprising the rotor. In its intended installation position, the rotor forms part of the electric machine. Finally, according to the invention, a motor vehicle comprising the electric machine, in particular as a traction machine, is proposed.The motor vehicle in question is therefore, in particular, a purely or hybrid-electrically powered motor vehicle.

[0008] The bearing seat body has a shaft body, which can be designed, in particular, as a hollow shaft body. The shaft body has a bearing seat in a section along its length, which is designed to be connected to an inner ring of a radial bearing for supporting the rotor shaft. Specifically, an interference fit is provided between an outer surface of the bearing seat and an inner surface of the inner ring to connect the inner ring and the rotor shaft.

[0009] Furthermore, the bearing seat body features a conduit arrangement, which includes a conduit with a channel opening that terminates at an end face of the shaft body. The conduit penetrates the shaft body along its longitudinal direction and completely traverses the bearing seat section of the shaft body in which the bearing seat is located. The conduit can be arranged parallel and / or obliquely to a longitudinal axis of the shaft body; for example, it can have a conduit section parallel to the longitudinal axis of the shaft body and / or an oblique or skewed section relative to the longitudinal axis of the shaft body.Furthermore, the respective conduit section can have a kink, meaning that a second straight conduit section connects to a first straight conduit section starting from the end face. The point where the first straight conduit section and the second straight conduit section meet – i.e., the kink – can be located within the bearing seat length section. Alternatively or additionally, the respective conduit section can have a material recess at the conduit opening and / or at a second conduit opening located at the other end of the same conduit, enlarging the opening to facilitate the insertion of the associated conduit element.

[0010] The bearing seat body further comprises a compensating opening arrangement, which includes a compensating opening with a terminal that opens onto the same end face of the shaft body as the conduit channel. The compensating opening penetrates the shaft body along its longitudinal direction. The compensating opening can be arranged parallel or obliquely to the longitudinal center axis of the shaft body. Starting from the end face where the conduit channel and the compensating opening open, the compensating opening extends completely through the bearing seat section of the shaft body in which the bearing seat is located. Therefore, the compensating opening has at least one section that extends completely through the bearing seat section in its longitudinal direction. It is specifically designed that the compensating opening is shorter than the conduit channel along its longitudinal direction.

[0011] Naturally, the conduit arrangement can be designed to have two or more such conduits, particularly an even number. In such a case, it is advantageous for the conduits to be evenly spaced relative to each other along one circumferential direction of the shaft body and arranged in pairs opposite each other, offset by 180 degrees. Alternatively or additionally, the compensating opening arrangement can have two or more such compensating openings, either an even or odd number.

[0012] By forming the compensating opening arrangement, the bearing seat body is selectively weakened in the bearing seat section of the shaft body. This targeted weakening results in the bearing seat section exhibiting lower resistance to deformation than the rest of the shaft body. This is advantageous because, when creating the interference fit between the outer surface of the shaft body or bearing seat and the inner surface of the inner bearing ring, the bearing seat section will more easily and uniformly conform to the shape of the inner bearing ring. In particular, an interference or press fit is used to connect the shaft body to the radial bearing, which has a greater overlap between the inner diameter of the inner bearing ring and the outer diameter of the bearing seat than previously possible. This creates a particularly tight connection between the bearing seat and the inner bearing ring, with the bearing seat body being pressed firmly against the bearing seat.The bearing seat is deformed in the desired manner within the corresponding section of its length. It does not become out of round; instead, due to the strategically placed compensating opening(s), it conforms to the inner surface of the bearing's inner ring. In other words, the inner surface of the inner ring sits flush against the outer surface of the bearing seat body along its entire circumference. This results in a particularly low dynamic imbalance of the bearing seat body during rotation, and consequently, a smoother, quieter operation of the electric machine. Therefore, during operation, the radial bearing only needs to absorb or compensate for these exceptionally small dynamic imbalances, allowing for the use of less robust bearings than previously possible. These bearings are lighter, enabling a more energy-efficient design for the electric machine.

[0013] In the rotor shaft, the rotor shaft body and the bearing seat body are rotationally fixed to each other along a common longitudinal axis of the rotor shaft. The rotor shaft body, which is designed to support the field coil assembly, and the bearing seat body are, for example, initially manufactured separately and then joined together by force-fit, form-fit, and / or material-fit. Furthermore, it is conceivable that the rotor shaft body and the bearing seat body—particularly including the conduit assembly and the compensating opening assembly—are formed integrally. To manufacture the conduit assembly and the compensating opening assembly, if they do not have a perfectly straight profile, during the simultaneous / integral production of the bearing seat body and the rotor shaft body, an additive manufacturing process can be employed.In particular, each conductor channel is continued by means of a respective connecting channel that penetrates the rotor shaft body.

[0014] In a possible further development of the bearing seat body, the channel opening, or—if the conduit arrangement has two or more conduit channels—the channel openings, and the opening opening, or—if the compensating opening arrangement has two or more compensating openings—the opening openings, are arranged on a common bolt circle or along a common bolt circle on the end face. In other words, the center point of each channel opening and the center point of each opening opening lie on the common bolt circle. Furthermore, in this further development, the openings, i.e., the channel and opening openings, are equidistant from each other along the bolt circle. This means that the bolt circle is divided into arcs of equal size by the centers of the openings.

[0015] In an alternative embodiment of the bearing seat body, the channel outlet or – if the conduit arrangement has two or more conduits – the channel outlets are arranged on a channel outlet circle, with the opening outlet or – if the compensating opening arrangement has two or more compensating openings – the opening outlets being arranged on an opening outlet circle that differs from the channel outlet circle. The channel outlet circle and the opening outlet circle are each a bolt circle along which the channel outlet(s) or opening outlet(s) is / are arranged. The channel outlet circle and the opening outlet circle differ from each other in that they have different diameters.In this further development, the openings, that is, both the channel and the openings, are designed and arranged such that they each radially tangentially touch a common circumferential circle. It follows that the channel openings in this further development have a different diameter—that is, a smaller or larger diameter—than the openings. Because the openings radially tangentially touch the common circumferential circle, the bearing seat has a constant wall thickness along its circumference, resulting in particularly uniform deformation when the inner bearing ring is pressed on.

[0016] It can therefore be seen that the bearing seat body can be adapted to different requirements or boundary conditions particularly easily during its manufacture, especially by selecting one of the further developments described above.

[0017] According to another possible embodiment, which can be combined with both of the aforementioned further developments, the conduit channel section of the conduit, which runs completely through the bearing seat length section, and the compensating opening section of the compensating opening, which also runs completely through the bearing seat length section, are each designed as a straight hollow cylinder. This makes the conduit channel section and the compensating opening section particularly easy to manufacture, for example, by drilling.

[0018] The conduit section and the equalization opening section can be manufactured even more easily, particularly in a single operation, if – as provided in another possible embodiment – ​​the diameter of the conduit section and the diameter of the equalization opening section are the same. This makes it possible, in particular, to manufacture the conduit section and the equalization opening section using the same tool, for example, the same drilling or milling tool.

[0019] The manufacturing of the conduit section and the compensating opening section can be further simplified. According to another possible embodiment, a longitudinal center axis of the conduit section and the longitudinal center axis of the shaft body form a first angle with each other, while a longitudinal center axis of the compensating opening section and the longitudinal center axis of the shaft body form a second angle with each other. The first and second angles have the same measure, i.e., they are equal in magnitude, and are, in particular, greater than 0 degrees and less than 90 degrees. This means that the conduit section and the compensating opening section are, for example, both arranged obliquely or skewed with respect to the longitudinal center axis of the shaft body.When considering each angle, it is assumed that it lies in an imaginary plane containing both the longitudinal center axis of the shaft body and the longitudinal center axis of the conduit or compensating opening section—essentially a plane defined by the shaft body's longitudinal center axis and a radius of the shaft body. In any case, the conduit section and the compensating opening section are particularly easy to manufacture, as the time-consuming repositioning of a tool after one section has been produced is unnecessary for manufacturing the other. For example, it is conceivable to simply rotate the shaft body around its longitudinal center axis, while the angle between the tool and the shaft body's longitudinal center axis remains unchanged.

[0020] According to another possible embodiment, the compensating opening is designed as a blind hole, which terminates axially, in particular, at the same point as the bearing seat section. In other words, the compensating opening has a closed opening or hole bottom, which can be, for example, circular disc-shaped, conical, or shaped like a spherical cap. The opening bottom of the compensating opening, designed as a blind hole, can extend longitudinally from the end face behind a distal end of the bearing seat. This design of the compensating opening allows the shaft body to be more easily deformed in the bearing seat section for pressing in the inner bearing ring, while the remaining shaft body remains unchanged and stable. Further features of the invention may become apparent from the claims, the figures, and the description of the figures.The features and combinations of features mentioned above in the description, as well as the features and combinations of features shown below in the figure description and / or in the figures alone, can be used not only in the combination specified in each case, but also in other combinations or on their own, without leaving the scope of the invention.

[0021] The drawing shows in

[0022] Fig. 1 shows a schematic and cutaway view of a rotor shaft having a bearing seat body,

[0023] Fig. 2 shows a perspective view of the bearing seat body along a shaft body longitudinal center axis,

[0024] Fig. 3 shows a perspective view of the bearing seat body and in

[0025] Fig. 4 shows a perspective view of the bearing seat body along the longitudinal center axis of the shaft body in an alternative further development.

[0026] The following section describes a bearing seat body 1 for a rotor shaft 3 of an electric machine, the rotor shaft 3, a rotor comprising the rotor shaft 3, the electric machine, and a motor vehicle comprising the electric machine. In the figures, identical and functionally equivalent elements are designated with the same reference numeral. The rotor, the electric machine, and the motor vehicle are not shown in the figures.

[0027] The motor vehicle can be driven purely electrically or hybrid-electrically and therefore has one or more electric machines as its traction or drive machine(s). Each electric machine has a fixed stator and rotor, the rotor being rotatably mounted relative to the stator. The electric machine is a separately excited synchronous machine, which is why the rotor, which has the rotor shaft 3, also has a field coil assembly that is fixedly mounted to a rotor shaft body 3a of the rotor shaft 3. The rotor shaft body 3a and the bearing seat body 1 are rotationally connected to each other in the rotor shaft 3.

[0028] The bearing seat body 1 forms one rotor shaft end of the rotor shaft 3, allowing the rotor shaft 3 to be rotatably mounted, for example, in a housing of the electric machine. Logically, the rotor shaft 3 has a second rotor shaft end (not shown), which can be designed analogously to the rotor shaft end or bearing seat body 1 described below. In other words, the rotor shaft 3 can have two bearing seat bodies 1, each forming one of the rotor shaft ends.

[0029] Fig. 1 shows a schematic, sectional view of one of the two axial ends of the rotor shaft 3. It can be seen in Fig. 1 that a shaft body 2 of the bearing seat body 1 is designed as a hollow shaft body. The bearing seat body 1 has a channel arrangement 4, which includes a channel 5 – in this example (see Fig. 2), two channels 5. Each channel 5 penetrates the shaft body 2 along its longitudinal direction x. The channels 5 each have a channel opening 6, through which the respective channel 5 opens at an end face 7 of the shaft body 2. The channels 5 can, for example, each be designed as a bore, whereby the bore in Fig. 1 may have been formed from the left or from the right. Furthermore, it is possible that both a bore from the left and a bore from the right were formed to create the same channel 5.It is conceivable that the two bores were machined at different angles, so that the corresponding conduit 5 has a kink (not shown). Figure 1 further shows that each conduit 5 has a material recess 5c, which significantly facilitates the insertion of a conduit element (not shown) into the conduit 5. Figure 1 also shows that each conduit 5 can connect to a continuation channel 3b of the rotor shaft body 3a. If the bearing seat body 1 and the rotor shaft body 3a are formed integrally or bonded together, it is possible that the continuation channel 3b and the associated conduit 5 were produced by a single manufacturing process, such as drilling together.

[0030] The bearing seat body 1 also has a compensating opening arrangement 8, which includes a compensating opening 9 – in particular, a plurality of compensating openings 9, here in the example (see Fig. 2) six compensating openings 9. Each compensating opening 9 penetrates the shaft body 2 along its longitudinal direction x. The compensating openings 9 each have an opening 10, by means of which the respective compensating opening 9 opens at the same end face 7 as the conduit channels 5. A bearing seat 11 of the bearing seat body 1 is designed to be connected to a bearing inner ring 12 of a radial bearing 13 for supporting the bearing seat body 1 or the rotor shaft or the rotor. The bearing seat 11 is formed by a portion of an outer surface 14 of the shaft body 2. Starting from the end face 7, the compensating openings 9 pass completely through a bearing seat length section 15 of the shaft body in which the bearing seat 11 is arranged.In other words, the compensating openings 9 each have a compensating opening section 9a extending from the end face 7 and extending along the longitudinal direction x at least as far as the compensating opening section 9a completely traverses the bearing seat length section 15. Furthermore, the conduit channels 5 each have a conduit channel section 5a that also completely traverses the bearing seat length section 15 along the longitudinal direction x.

[0031] Fig. 2 shows a perspective view of the bearing seat body 1 along a longitudinal center axis 16 of the shaft body 2. It can be seen that, in the example described here, the channel openings 6 and the openings 10 are arranged on a common bolt circle 17 of the end face 7, and the openings 6 and 10 are equidistant from each other along the bolt circle 17. It can also be seen in Fig. 2 that the guide channels 5 are evenly spaced relative to each other along a circumferential direction of the shaft body – thus along the bolt circle 17 – and are arranged radially opposite each other in pairs offset by 180 degrees. Figs. 2, 3, and 4 further show that a filler element F is inserted into each of the guide channels 5, for example, by injection molding the respective filler element F into the corresponding guide channel 5.The respective conductor element, which was arranged in the corresponding conductor channel 5, may have been overmolded with the injection molding material, which makes it particularly secure in the corresponding conductor channel 5.

[0032] Fig. 1 also shows that the conduit sections 5a and the compensating opening sections 9a are each designed as a straight hollow cylinder and have the same diameter 18. In other words, the diameter of the conduit section 5a and the diameter of the compensating opening section 9a are the same. Fig. 1 also shows that the conduit sections 5a and the compensating opening sections 9a each have a longitudinal center axis 5b. The respective longitudinal center axis 5b and the shaft body longitudinal center axis 16 form a first angle α with each other, and a second angle β with each other, where α = β. Further details can be seen in Fig. 1.1 shows that the angles a, ß are each different from both 0 degrees and 90 degrees, which means that the conduit sections 5a and the compensating opening sections 9a are arranged obliquely in relation to the longitudinal center axis 16 of the shaft body.

[0033] Furthermore, as can be seen in Fig. 1, the compensating openings 9 are each designed as a blind hole 19, which in this example ends axially together with the bearing seat length section 15. The respective compensating opening has a closed opening or hole bottom, which in this case is designed in a circular disk shape and which ends behind the bearing seat 11 in the longitudinal direction x starting from the end face 7.

[0034] Fig. 3 shows a perspective view of the bearing seat body 1, showing that the shaft body 2 can be designed as a stepped shaft body or as a stepped hollow shaft body, with the guide channels 5 and the compensation openings 9 penetrating into a material of the shaft body 2 from the end face 7.

[0035] Fig. 4 shows a perspective view of an alternative embodiment of the bearing seat body 1 along the longitudinal center axis 16 of the shaft body. This alternative embodiment differs from the embodiment described above by a different design of the compensating openings 9. Apart from this, the above description applies analogously to the alternative embodiment of the bearing seat body 1.

[0036] In contrast to the embodiment described above, the channel outlets 6 are arranged on a channel outlet circle 20, whereas the opening outlets 10 are arranged on an opening outlet circle 21 that differs from the channel outlet circle 20. The channel outlet circle 20 and the opening outlet circle 21 differ from each other in that they have different diameters; in this case, the channel outlet circle 20 has a smaller diameter than the opening outlet circle 21. According to this embodiment, the outlets 6 and 10 are also designed and arranged such that they each radially tangent to a common circumferential circle 22. In other words, both the channel outlets 6 and the opening outlets 10 radially tangent to the common circumferential circle 22, particularly as shown in Fig. 4.4 further to recognize that in this further development the channel outlets 6, and consequently the pipe channel sections 5a, have a different - here larger - diameter than the opening outlets 10 or the compensating opening sections 9a.

[0037] Due to the compensating opening arrangement 8, the bearing seat body 1 is specifically weakened in the bearing seat length section 15, and thus more easily or uniformly deformable than the remaining shaft body 2 without the compensating opening arrangement 8. This allows for a more favorable manufacturing process when a

[0038] The press fit or interference fit 23 between the outer surface 14 or the bearing seat 11 and the inner bearing ring 12 allows the bearing seat length section 15 to be deformed more easily and uniformly according to the shape of the inner bearing ring 12. Thus, a solution is provided for the task outlined at the beginning: to create a particularly reliable connection between a bearing seat of a rotor shaft and a radial bearing designed to support the rotor shaft.

[0039] Reference symbol list

[0040] 1 bearing seat body

[0041] 2 wave bodies

[0042] 3 Rotor shaft

[0043] 3a Rotor shaft body

[0044] 3b Continuation Channel

[0045] 4. Cable duct arrangement

[0046] 5 cable duct

[0047] 5a Conduit section

[0048] 5b Longitudinal center axis

[0049] 5c Material recess

[0050] 6 Canal Mouth

[0051] 7 Front

[0052] 8 Compensation opening arrangement

[0053] 9 Compensation opening

[0054] 9a Compensation opening section

[0055] 9b Longitudinal center axis

[0056] 10 Opening mouth

[0057] 11 bearing seat

[0058] 12 inner bearing ring

[0059] 13 radial bearings

[0060] 14 Outer shell area

[0061] 15 Bearing seat length section

[0062] 16 Shaft body longitudinal center axis

[0063] 17-inch bolt circle

[0064] 18 Diameter measurement

[0065] 19 dead end

[0066] 20 Canal estuary district

[0067] 21 Opening estuary

[0068] 22 Circumference

[0069] 23 Press fit or interference fit x Longitudinal direction a First angle ß Second angle

[0070] F Filler

Claims

Patent claims 1. Bearing seat body (1) for a rotor shaft (3) of an electric machine, comprising: - a conduit arrangement (4) comprising a conduit channel (5) which penetrates a shaft body (2) of the bearing seat body (1) along its longitudinal extension direction (x) and opens with its channel opening (6) at an end face (7) of the shaft body (2), - a compensating opening arrangement (8) comprising a compensating opening (9) which - penetrates the wave body (2) along the longitudinal direction (x), - with its opening (10) on the front side (7) opens and, - starting from the end face (7), completely passes through a bearing seat length section (15) of the shaft body (2) in which a bearing seat (11) of the bearing seat body (1) is arranged.

2. Bearing seat body (1) according to claim 1 , characterized in that the channel opening (6) or, if the conduit channel arrangement (4) has two or more conduit channels (5), the channel openings (6a) and the opening opening (10) or, if the compensating opening arrangement (8) has two or more compensating openings (9), the opening openings (10) are arranged on a common bolt circle (17) of the end face (7), and the openings (6, 10) are equidistantly spaced apart from each other along the common bolt circle (17).

3. Bearing seat body (1) according to claim 1, characterized in that the channel opening (6) or, if the conduit channel arrangement (4) has two or more conduit channels (5), the channel openings (6) are arranged on a channel opening circle (20), wherein the opening opening (10) or, if the compensating opening arrangement (8) has two or more compensating openings (9), the opening openings (10) are arranged on an opening opening circle (21) different from the channel opening circle (20), wherein the openings (6, 10) are radially tangential to a common circumferential circle (22).

4. Bearing seat body (1) according to one of the preceding claims, characterized in that a conduit channel section (5a) of the conduit channel (5) which completely extends through the bearing seat length section (15) and a compensating opening section (9a) of the compensating opening (10) which completely extends through the bearing seat length section (15) are each designed according to a straight hollow cylinder.

5. Bearing seat body (1) according to claim 1 or 2 with reference to claim 4, characterized in that a diameter of the conduit section (5a) and a diameter of the compensation opening section (9a) are the same.

6. Bearing seat body (1) according to claim 4 or 5, characterized in that a longitudinal center axis (5b) of the conduit section (5a) and a shaft body longitudinal center axis (16) enclose a first angle (a) with each other, wherein a longitudinal center axis (9b) of the compensating opening section (9a) and the shaft body longitudinal center axis (16) enclose a second angle (ß) with each other, and the angles (a, ß) have the same angular measure, in particular differing from 0 degrees and from 90 degrees.

7. Bearing seat body (1) according to one of the preceding claims, characterized in that the compensating opening (9) is designed as a blind hole (19) which in particular ends axially together with the bearing seat length section (15).

8. Rotor shaft (3) with a bearing seat body (1) designed according to one of the preceding claims, which is connected to a rotor shaft body (3a) of the rotor shaft (3) in a rotationally fixed manner.

9. Rotor for an electric machine, comprising the rotor shaft (3) designed according to claim 8, wherein a field coil arrangement is fixed to the rotor shaft body (3a) in a rotationally fixed manner.

10. Electric machine with a rotor designed according to claim 9.

11. Motor vehicle comprising an electric machine designed according to claim 10.

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