阅读说明：本技术 特别用于电或混合动力车辆的电机单元 (Electric motor unit, in particular for an electric or hybrid vehicle ) 是由 福尔克尔·迪茨 于 2016-09-29 设计创作，主要内容包括：本发明涉及一种电机单元,其包括具有定子(22)和带有转子轴(18)的转子(20)的电机(2)。定子(22)与无接触的转动力矩测量装置(6)的静止的部件(28)连接并且转子轴(18)与其转动的部件(30)连接。转动的部件(30)设计用于,测量转子轴(18)的由转动力矩引起的扭力并且将测量值无接触地发送到静止的部件(28)处。电机单元特别设置用于电或混合动力车辆。(The invention relates to an electric machine unit comprising an electric machine (2) having a stator (22) and a rotor (20) with a rotor shaft (18). The stator (22) is connected to a stationary part (28) of the contactless rotational torque measuring device (6) and the rotor shaft (18) is connected to a rotating part (30) thereof. The rotating component (30) is designed to measure the torque of the rotor shaft (18) caused by the torque moment and to transmit the measured value to the stationary component (28) without contact. The electric machine unit is provided in particular for an electric or hybrid vehicle.)

1. An electric motor unit having an electric motor (2), wherein the electric motor (2) comprises a stator (22) and a rotor (20) having a rotor shaft (18), characterized in that a stationary part (28) of a contactless rotation torque measuring device (6) is connected to the stator (22) and a rotating part (30) of the contactless rotation torque measuring device is connected to the rotor shaft (18), and the rotating part (30) is designed to measure a rotation torque of the rotor shaft (18) caused by the rotation torque and to transmit the measured value contactlessly to the stationary part (28).

2. An electric machine unit as claimed in claim 1, characterized in that the electric machine unit is used in an electric or hybrid vehicle.

3. The motor unit according to claim 1 or 2, characterized in that the rotating component (30) has a magnetic field generator (34, 54) which is designed to vary the magnetic field generated by the anti-magnetostrictive effect depending on the rotational torque transmitted by the rotor shaft (18) while making full use of the anti-magnetostrictive effect, in that the stationary component (28) comprises a magnetic field sensor (36) which is designed to detect the magnetic field generated by the magnetic field generator (34, 54), and in that an evaluation unit (56) is connected to the magnetic field sensor (36) which is designed to determine the rotational torque acting at the rotor shaft (18) from the magnetic field variations.

4. A motor unit according to claim 3, characterized in that the magnetic field generator (34, 54) and the magnetic field sensor (36) are arranged at the same axial position (32) of the motor (2).

5. The motor unit according to claim 3 or 4, characterized in that the magnetic field generator (34, 54) and the magnetic field sensor (36) are arranged radially spaced apart from each other.

6. The motor unit according to any one of claims 3 to 5, characterized in that the magnetic field generator (34) is configured as a permanent magnet.

7. The motor unit according to claim 6, characterized in that the magnetic field generator (34) is configured as magnetized or magnetizable ferrite.

8. The motor unit according to any one of claims 3 to 5, characterized in that the rotor shaft (18) consists of a magnetizable material at least in the region of the magnetic field generator (34), and the rotor shaft (18) is correspondingly magnetized in the region of the magnetic field generator (34).

9. The motor unit as claimed in claim 8, characterized in that the rotor shaft (18) is constructed in one piece with the magnetic field generator (34).

10. The motor unit according to any one of claims 3 to 9, characterized in that the magnetic field sensor (36) is designed for detecting an axial component of the magnetic field generated by the magnetic field generator (34, 54).

11. The motor unit according to any one of claims 3 to 10, characterized in that the motor (2) comprises a bearing end cap (14), in which the rotor shaft (18) is supported, and in that the magnetic field sensor (36) is fixedly connectable with the bearing end cap (14).

12. The motor unit according to claim 11, characterized in that the magnetic field sensor (36) is embodied in a detachable manner again integrated in the bearing end cap (14).

13. The motor unit according to any one of claims 3 to 10, characterized in that the rotor shaft (18) is supported in a bearing end cap (14) by means of a rolling bearing (26), in which rolling bearing (26) rolling bodies are arranged at a rolling surface (38), and in that the magnetic field sensor (36) is fastened at the rolling surface (38) of the rolling bearing (26) which is fixedly arranged in the bearing end cap (14).

14. The motor unit according to any one of claims 3 to 13, characterized in that the magnetic field sensor (36) is configured as a hall probe.

15. The electrical machine unit according to any one of claims 3 to 13, characterized in that the magnetic field sensor (36) is configured as an electrical coil.

16. The motor unit according to any one of claims 1 to 15, characterized in that the electric motor (2) is connected to a power and control unit (40), wherein the power and control unit (40) is designed to control the power of the electric motor (2) as a function of a control signal of a higher-level control device (70), and the contactless rotational torque measuring device (6) is connected to the power and control unit (40).

17. The motor unit according to claim 16, characterized in that the power and control unit (40) is arranged at the motor (2) and the magnetic field sensor (36) magnetically shields (60) the power and control unit (40).

18. The motor unit according to any one of claims 1 to 17, characterized in that the contactless rotation torque measuring device (6) is arranged in a separate section in the axial extension of the rotor shaft (18).

19. The motor unit according to claim 18, characterized in that the contactless rotational torque measuring device (6) is arranged in a transmission section (80) which is mechanically operatively connected to the rotor shaft (18) and can be driven by the rotor shaft (18).

20. The electrical machine unit according to any one of claims 1 to 19, characterised in that the contactless rotational torque measuring device (6) is arranged at a transmission shaft (86) of a vehicle transmission, which is arranged effectively parallel to the rotor shaft (18), in order to measure the rotational torque transmitted by a transmission section (80) and to transmit it contactlessly to the stationary component (28) of the contactless rotational torque measuring device (6).

Technical Field

The invention relates to an electric machine unit, in particular for an electric or hybrid vehicle, having an electric machine, wherein the electric machine comprises a stator and a rotor having a rotor shaft.

Background

An electric machine is generally understood to be an electromechanical converter, which can have various operating modes. It can therefore be used as an electric drive only or as a generator only or alternatively as an electric drive or as a generator. For example, an electric machine in an electric or hybrid vehicle operates in a motor operating mode when driving the vehicle and in a generator operating mode when braking.

In general, it is important for the operation of an electric machine to know which rotational torque is currently transmitted via the rotor shaft of the electric machine.

It is known that the torque applied to the electric machine is determined directly via the current electrical variable at the electric machine.

Various types of torsion sensors are also known from the prior art for the purpose of directly mechanically carrying out load detection on the shaft. Which is arranged, for example, on the rotor shaft. Thus, a strain sensor (shortly DMS) can be arranged on the shaft in order to detect the mechanical load on the shaft. However, this arrangement has the disadvantage that the DMS must be connected via signal lines to a corresponding control device, which is physically connected in order to be able to carry out the signal transmission. In particular, this contact is inconvenient in the case of rotatable shafts, since slip rings or similar contact interfaces have to be installed for signal transmission.

Furthermore, contactless methods for measuring a rotational torque are known, which use the inverse magnetostrictive effect (also referred to as magnetoelastic effect (magnetoelastic effect) or the vilari effect (Villari-effect)) for measuring the rotational torque on a shaft. This effect is greatest in ferromagnetic materials and is present in changes in the susceptibility to mechanical stress. Such a contactless method of measuring a rotational torque is widely used in sensor bearings of the pedelc ("Pedal Electric Cycle", short for Pedal Electric vehicles). However, the geometry of such a contactless measurement method of the rotational torque in the sensor bearing of petelec is sometimes unreliable and/or prone to interference, since for the measurement of the rotational torque, precise positioning of the measured, respectively detected sensor bearing component relative to the rotating component is taken into account. This is achieved with the prior art mainly by means of costly additional structures of the housing, in particular additional carriers or sleeve elements, which are mostly made of plastic with low mechanical stability. Furthermore, the problem with the aforementioned petelec is that the integration of the contactless rotational torque measurement method into a complex (electrified) overall system is only possible with high effort, since such sensor bearings have hitherto been able to transmit only reaction-free control signals. Furthermore, the sensor bearing is not sufficiently shielded from the direct environmental electrical interference influences with the prior art.

Disclosure of Invention

The object of the present invention is to structurally and functionally improve the aforementioned prior art. In particular, the electric machine should have an improved device for measuring the rotational torque.

This object is achieved by the motor unit featuring the present invention. In the case of the motor unit described at the outset, the stationary part of the contactless torque measuring device is connected to the stator, and the rotating part of the contactless torque measuring device is connected to the rotor shaft, and the rotating part is designed to measure the torque of the rotor shaft caused by the torque and to transmit the measured value to the stationary part in a contactless manner.

The contactless design of the rotational torque measuring device is significantly simplified and also its reliability is increased compared to the design with a wired connection of the DMS.

Furthermore, it is advantageously possible to control or regulate the drive or the recuperation power of the electric motor as a function of the measured, respectively detected rotational torque.

Furthermore, in an electric or hybrid vehicle designed with the machine unit according to the invention, the driving command, which is transmitted by the driver with the aid of the pedal force to the driving pedal (known as "accelerator") and transmitted via a so-called driving pedal module control (FPM control) to the motor control or to the converter of the electric or hybrid vehicle, can be tested for plausibility with the aid of the measured respectively detected rotational torque. In this way, additional diagnostic functions can be provided for the driving pedal and/or the driving pedal module control.

Another advantage can be that the mechanical loads occurring in special vehicle situations are limited to the rotor shaft in order to minimize wear of mechanically moving parts of the electric machine and/or to prevent the risk of damage at the electric machine or adjacent components. The rotational torque on the rotor shaft is limited in this case, for example, by means of a method implemented in the motor control device.

Another advantage can be that the drive power of the electric machine is limited to a specific characteristic curve. The power output of the electric machine can thus be controlled, for example, via a corresponding characteristic curve, in such a way that the highest possible travelable distance is achieved with the provision of stored energy in the energy store, so-called path-available distance being achieved.

On the basis of the advantages of the above-described embodiments, it is now also possible to equip the rotor shaft with a rotational torque detection system for an electric or hybrid drive. The instantaneous value of the torque can be used in various drive variants, in particular also in vehicles, for drive control in the control device and/or the converter. Alternatively, the momentary value can also take into account an electronic on-board diagnosis (E-OBD) for the drive control.

An advantageous embodiment of the invention provides that the rotating component has a magnetic field generator which is designed to vary the magnetic field generated by the anti-magnetostriction effect as a function of the rotation torque transmitted by the rotor shaft while making full use of the anti-magnetostriction effect, that the stationary component comprises a magnetic field sensor which is designed to detect the magnetic field generated by the magnetic field generator, and that an evaluation unit is connected to the magnetic field sensor, which is designed to determine the rotation torque acting on the rotor shaft from the magnetic field variations, wherein the magnetic field generator and the magnetic field sensor are arranged at the same axial position of the electric machine and, advantageously, are arranged radially spaced apart from one another. The improved design of the electric machine according to the invention makes it possible to measure the rotational force acting on the rotor shaft with a high degree of accuracy also in environments loaded with a high level of disturbance. In this case, the change in the magnetization of the magnetic field generator is measured via the antimagnetic effect by means of a stress which is mechanically derived from the torsional force of the rotor shaft.

A further particularly advantageous embodiment of the invention provides that the magnetic field generator is designed as a permanent magnet, in particular as a magnetized or magnetizable ferrite, and that the rotor shaft is designed in one piece with the magnetic field generator, and that the rotor shaft is made of a magnetizable material at least in the region of the magnetic field generator, and that the rotor shaft is correspondingly magnetized in the region of the magnetic field generator, and that the magnetic field sensor is designed to detect an axial component of the magnetic field generated by the magnetic field generator. The particular one-piece construction of the rotor shaft and the magnetic field generator has the advantage that no notches or recesses have to be introduced in the circumferential direction of the rotor shaft for using a separate magnetic field generator. The cross section of the rotor shaft at the location of the magnetic field generator is therefore reduced without change, and the transmittable rotational torque is therefore not reduced. The rotor shaft is particularly advantageously embodied as a hollow shaft.

Advantageously, the invention also provides that the electric machine comprises a bearing shield in which the rotor shaft is supported, and that the magnetic field sensor can be fixedly connected to the bearing shield and can be embodied, in particular, again detachably integrated in the bearing shield. The rotor shaft is embodied as a hollow shaft, which improves the cooling of the electric machine. By conducting a fluid or gas, possibly in the form of a coolant or in the form of oil, the rotor shaft can be flowed through from the inside by the fluid. This enables an improved removal of the operating heat of the electric machine via the fluid.

A further advantageous embodiment of the invention provides that the rotor shaft is mounted in a bearing end cap by means of a rolling bearing, in which rolling bearing rolling bodies are arranged at the rolling surfaces, and that the magnetic field sensor is fastened to the rolling surfaces of the rolling bearing, which rolling surfaces are arranged fixedly in the bearing end cap, wherein the magnetic field sensor is designed as a hall probe or as an electrical coil. The integration of the magnetic field sensors into the outer bearing ring, respectively into the rolling surfaces of the rolling bearing, which are arranged fixedly with the bearing end caps, results in a compact design of the motor unit.

A further advantageous embodiment of the invention provides that the electric machine is connected to a power and control unit, wherein the power and control unit is designed to control the power of the electric machine as a function of a control signal of a superordinate control device, and the contactless rotational torque measuring device is connected to the power and control unit, wherein the power and control unit is arranged on the electric machine and the magnetic field sensor magnetically shields the power and control unit. The magnetic shielding of the magnetic field generator allows the use of a rotational torque measuring device in the vicinity of the electrical and electronic circuitry, which is sensitive to electromagnetic interference fields. The magnetic shielding also protects the magnetic field sensor from high magnetic interference fields, as they are also generated by the power unit.

A further advantageous embodiment of the invention provides that the contactless torque measuring device is arranged in a separate section of the axial extension of the rotor shaft, in particular in a transmission section which is mechanically operatively connected to the rotor shaft and can be driven by the rotor shaft, wherein the contactless torque measuring device is arranged on a transmission shaft of the vehicle transmission which is arranged effectively parallel to the rotor shaft, in order to measure the torque transmitted by the transmission section and to transmit it contactlessly to a stationary component of the contactless torque measuring device. By arranging the rotation torque measuring device in a separate section in the axial extension of the rotor shaft, alternatively in an arrangement effectively parallel to the rotor shaft, the physical distance to the electrical and electronic circuitry, which is sensitive to electromagnetic interference fields, can be extended. This can be used for better magnetic shielding and also to protect the magnetic field sensor from high magnetic interference fields, as they are also generated by the power unit. It has proven to be particularly advantageous if the separate section is a transmission section which is mechanically coupled to the rotor shaft, so that the rotational torque to be transmitted via the rotor shaft is guided via the transmission section.

Drawings

The above features, characteristics and advantages of the present invention and the manner and method of accomplishing the same will become more apparent from the following description of the embodiments, which is set forth in detail in connection with the accompanying drawings. Here, it is schematically shown that:

FIG. 1 is a sectional view of a motor unit with a motor and a first variant of a contactless rotational torque measuring device arranged at its bearing end cap,

FIG. 2 is a sectional view of a motor unit with a second variant of the motor with an integrated power and control unit and a contactless rotary torque measuring device,

FIG. 3 is a block diagram of a motor unit having a turning torque control device, and

fig. 4 is a schematic illustration of an electric machine unit with a transmission section which is mechanically coupled to the rotor shaft of the electric machine.

Detailed Description

Before describing the illustrated embodiments in detail, a brief background of known mechanical workings between torque force and turning torque or torques is first presented.

When a turning moment causes a torsion (torsional) of a rod, beam or axle, it is referred to as a torque. The torque acts on both ends of the twisted object as an active and a reactive. In a shaft with a constant cross section, the elastic torsion is proportional to the amount of torque. Similarly to in the control, only shear stress or torsional stress occurs in the torsional force. The torsional stress is defined as the ratio of the torque acting when the object is twisted to the resistance torque. The respective currently acting torque can be detected by measuring the respective current torque or torsion.

However, in practical applications several boundary conditions have to be taken care of. Only relatively small torsion angles should therefore occur in reversible or elastic torsion. Furthermore, no deformation or bending of the shaft cross section should occur during the twisting. However, this precondition can be observed in many application cases.

Fig. 1 shows a schematic longitudinal section through an electric machine 2, the electromechanical working parts of which are enclosed by a housing 4. A first variant of the contactless rotational torque measuring device 6 is connected to the housing 4.

The housing 4 comprises a first housing part 8 having a substantially cylindrical inner chamber 10. Bearing caps 12 and 14 are fastened to the two end sides of the housing part 8. Arranged rotationally symmetrically to the axis 16 is a rotor shaft 18, on which a rotor 20 of the electric machine 2 is fastened. A stator 22 of the electric machine 2 is likewise fastened to the first housing part 8 in a rotationally symmetrical manner to the axis 16. The rotor shaft 18 is designed here as a hollow shaft for improved cooling of the electric machine 2. The rotor shaft 18 can be flowed through from the inside by a fluid by introducing a flow-conducting body or gas, possibly in the form of a coolant or in the form of oil. This enables an improved removal of the operating heat of the electric machine 2 via the fluid.

The rotor shaft 16 is rotatably mounted in the two bearing covers 12, 14 by means of rolling bearings 24, 26. For example, its support in the bearing end cap 12 is realized via a fixed bearing and its support in the bearing end cap 14 is realized via a floating bearing (Loslager).

Via the rotor shaft 18, mechanical power is output by the electric machine 2 in the electric machine operating mode and mechanical power is received in the generator operating mode. These two operating states are indicated by the double arrow 27.

The contactless rotational torque measuring device 6 comprises a stationary part 28 which is fixedly connected to the housing 4 and a rotating part 30 which is fixedly connected to the rotor shaft 18. The stationary part 28 and the rotating part 30 are arranged at the same axial position at radial intervals, which is illustrated here by a dashed line 32.

The rotating component 30 comprises a magnetic field generator which changes its magnetic field via a reverse magnetostrictive effect in dependence on the torque acting on the rotor shaft 18. The rotor shaft 18 is made of a magnetizable material. The magnetic field generator is realized by annularly applied magnetization means 34 arranged along a circumferential line of the rotor shaft 18, which is shown in fig. 1 in dashed lines. Radially spaced from the annular magnetization 34 of the rotor shaft 18, a magnetic field sensor 36 is fixedly connected to the bearing end cap 14 of the housing 4. Two oppositely arranged magnetic field sensors 36 are provided here.

The magnetic field sensor 36 can be embodied as a hall sensor or as a wound electrical coil, which is filled with a ferromagnetic material, if appropriate. It is mounted in an oriented manner such that it can detect the axial component of the magnetic field generated by the magnetic field generator, here the annular magnetizing device 34.

Depending on the type of operation, the electric machine 2 outputs mechanical power via the rotor shaft 18, i.e. it operates in a motor operating mode, or it receives mechanical power, i.e. it operates in a generator operating mode. In an application as a drive electric vehicle, the rotor shaft 18 is mechanically coupled to a drive train of the electric vehicle, for example, directly or via a transmission. The rotor shaft 18 is twisted or twisted due to the elastic material properties when the electric vehicle is accelerating (motor mode) or decelerating (generator mode). On the other hand, this torsion generates torsional stresses in the rotor shaft 18 and in the permanent magnet ring 34, which change its magnetic flux. The magnitude of the magnetic flux is a parameter for the torsion. Via the previously described mechanical operating background, a torque moment corresponding to the torque can be represented via the known material properties of the rotor shaft 18, which can be used for controlling and regulating the electric machine 2, as will be described below.

The stationary part 28 of the first variant of the contactless rotational torque measuring device 6 is integrated into the floating bearing 26. The floating bearing 26 comprises an outer ring or rolling surface 38 which is mounted so as to be axially displaceable in the bearing end cap 14 and in which the rolling bodies of the floating bearing 26 are guided. The outer ring 38 extends in the axial direction beyond the region of the rolling bodies. At the inner side of the extension a magnetic field sensor 36 is fastened. Accordingly, the bearing of the magnetic field sensor 36 is embodied in one piece with the outer ring 38 of the floating bearing 26, which simplifies both the production and the assembly of the stationary component 28.

It is pointed out here that the bearing of the magnetic field sensor 36 can be embodied in one piece with the outer ring of the fixed bearing.

Fig. 2 shows a sectional view of a motor unit with a second variant of a contactless rotational torque measuring device. The electric machine 2 comprises a housing 4 with electromechanical components arranged in this way, as described in connection with fig. 1. However, a power and control unit 40 is flange-mounted in the axial direction on the bearing end cap 14 on the right on the electric machine 2 according to fig. 2, which differs from the embodiment according to fig. 1. The rotor shaft 18 is also designed as a solid shaft. A second variant of the contactless rotational torque measuring device 6 is arranged in the power and control unit 40 in an integrated manner.

The power and control unit 40 comprises electrical and electronic components for controlling the power and the rotational speed of the electric machine 2, as is described many times in the prior art.

The power and control unit 40 comprises a housing 42 in the interior 44 of which the electrical and electronic components of the power and control unit 40 are arranged. The right end of the housing 42 is designed as a third bearing end cap 48, where a further rolling bearing 50 is arranged for mounting the rotor shaft 18 extending there.

In contrast to the first variant of the contactless torque measuring device 6, the magnetic field sensor 36 is fastened in the second variant according to fig. 2 to an annular carrier 52 that is separate from the outer ring of the rolling bearing 50. The second variant of the contactless rotational torque measuring device 6 also differs from the embodiment of the rotating component 30 of the contactless rotational torque measuring device 6. The magnetic field generator is realized here by a permanent magnet 54, which is arranged in a circumferential recess or groove of the rotor shaft 18. In particular, this embodiment can be handled simply in the production in the case of large and/or heavy rotor shafts 18, but the transmittable rotational torque is reduced in the same diameter by the introduction of the grooves relative to the rotor shaft 18 without grooves.

The magnetic field sensor 36 is connected to an evaluation unit 56 arranged in the further housing 42 via a signal line 58. The evaluation unit 56 determines the rotational torque acting on the rotor shaft 18 from the magnetic field measured by the magnetic field sensor 36, taking into account the geometry and material properties of the rotor shaft 18, and provides the determined rotational torque of the control device of the electric machine 2.

The magnetic shielding in the form of a disk-shaped wall 60 made of a material with high magnetic permeability magnetically shields the power and control unit 40 from the rotational torque measuring device 6.

The block diagram according to fig. 3 shows the interaction of the rotational torque measuring device 6 with the higher-level control device 70 of the electric vehicle. The electric machine 2 is connected to an accumulator 71 via a power and control unit 40. The electrical energy flow is transmitted from the energy store via the power and control unit 40 to the electric machine 2 in the motor operating mode and is returned from the electric machine 2 to the energy store 71 in the generator operating mode. The motor and generator operating modes of the electric machine 2 are indicated in fig. 3 by the designation "M/G" and the energy flow is indicated in both directions by double arrows.

The currently acting torque measured by the torque measuring device 6 together with the evaluation unit 56 on the rotor shaft 18 of the electric machine 2 is supplied as an input variable to the higher-level control device 70. In addition, the variable of the currently acting torque is also fed directly to the power and control unit 40, which is to be shown by a dashed line. Further, the control device 70 at the upper stage also obtains a control command of the driver for a desired speed, such as "acceleration" or "deceleration". The control commands given by the driver of the electric vehicle are identified in fig. 3 by reference numeral 72. The control commands 72 are subsequently supplied to the superordinate control unit 70 via a travel pedal module 74. Additional control commands for the driver should be given via the input flag 76.

The higher-order control device 70 includes an operating characteristic curve for regulating the power of the electric machine 2, via which the respective operating parameter is controlled or regulated. For example, the driver can predetermine that the highest possible drivable distance (high path-effective distance) is achieved, taking into account the driving energy supplied. The rotational torque acting on the rotor shaft 18 or the load on the rotor shaft 18 can also be limited via the corresponding operating characteristic in order to minimize wear on the mechanically moving components. The operating state of the motor interior is likewise monitored, which is taken into account in the higher-level control device 70.

On the basis of the control signals preset by the driver and the internal operating and monitoring signals, control signals for the power and control unit 40 are generated in order to adjust the rotational torque on the rotor shaft 18 accordingly. The deviation of the current rotational torque on the rotor shaft 18 from the predetermined rotational torque as a guide variable is directly detected and can be adjusted accordingly.

Fig. 4 schematically shows an electric machine unit with a transmission section 80, which is mechanically coupled to the rotor shaft 18 of the electric machine 2. The transmission section 80 is arranged axially on the side of the rotor shaft 18 in a separate section of the axial extension. The transmission section 80 comprises a plurality of transmission components 81 to 84. The transmission components 81 to 84 are designed as gear stages which are in mechanical engagement with one another. For simplicity, fig. 4 omits the bearings for the transmission components 81-84. The transmission section 80 is mechanically fastened in a transmission housing 85 protected against external influences.

The contactless rotational torque measuring device 6 is not arranged directly on the rotor shaft 18 in fig. 4, as in the previous exemplary embodiment, but rather is arranged effectively parallel thereto. The contactless rotational torque measuring device 6 comprises a stationary part 28 and a rotating part 30 which are fixedly connected to a transmission housing 85. The rotating part 30 is arranged on a drive shaft 86 (in english called "link draft") arranged effectively parallel to the rotor shaft 18. The rotating part 30 can be, like the embodiment according to fig. 1, a magnetized part introduced into the drive shaft 86 during the production process, without the cross section of the geometry of the drive shaft 86 being reduced in each case by the magnetized part introduced during the production process. Alternatively, the rotating part 30 is a ring of permanent magnets, which is fastened in a rotationally fixed manner on the drive shaft 86. The stationary part 28 and the rotating part 30 are arranged at the same axial position, similarly to fig. 1, radially spaced apart from one another, here again indicated by a dashed line 32.

A power unit 40 is arranged around the electric machine 2 opposite the axis 88 of the drive shaft 86. Due to the large, and therefore structurally implemented, distance of the contactless torque measuring device 6 from the power unit 40, a highly magnetic decoupling of the contactless torque measuring device 6 from the power unit 40 results. This supports the magnetic shielding of the magnetic-field-sensitive components (not shown here), and is particularly directed to the high-magnetic-interference field-protective-case magnetic field sensor 36, as it is also generated by the power unit 40.

Although the invention has been illustrated and described in detail in the context of preferred embodiments, it is not limited to the examples disclosed, and other variants can be derived by the person skilled in the art without departing from the scope of protection of the invention.