Method for operating an electric traction machine, control device for an electric traction machine, electric traction machine and motor vehicle

Abstract

The invention relates to a method for operating an electric traction machine mounted on a support element of a motor vehicle by means of a bearing arrangement. A bearing impulse limit value predetermined for the bearing arrangement is characterized in that abutment of bearing elements of the bearing arrangement is avoided if one of the bearing elements is moved relative to the other bearing element with a bearing impulse that has at most the bearing impulse limit value. Before the start of an actual torque change, it is determined whether changing a currently provided torque to a target torque (S6) with a predetermined, first torque gradient would cause a first bearing impulse that has a first bearing impulse value that is greater than the bearing impulse limit value (S4).If this is the case, the traction machine is controlled to execute a change start step (S7) at the beginning of changing the current torque, in which the current torque is changed with a second torque gradient that causes a second bearing pulse whose second bearing pulse magnitude is at most as large as the bearing pulse limit magnitude. Furthermore, the invention relates to a control device, an electric traction machine, and a motor vehicle.

Description

[0001] The present invention relates to a method for operating an electric traction machine of a motor vehicle. Furthermore, the invention relates to a control device for an electric traction machine for a motor vehicle, wherein the control device is designed to carry out the method. Furthermore, the invention relates to an electric traction machine having such a control device, as well as to a motor vehicle with such an electric traction machine.

[0002] The function of engine mounts in motor vehicles is to support engines, meaning they provide a mechanical connection between the engine and a supporting element, particularly the vehicle body. A key requirement is to prevent vibrations generated within the engine (e.g., an electric traction motor, an internal combustion engine, a transmission, etc.) from being transmitted to the vehicle body. This would result in disruptive noise in the vehicle interior, significantly negatively impacting occupant comfort. Furthermore, the amount of exterior noise that may be emitted by a vehicle is legally limited. To meet these requirements, elastomer or hydro mounts are currently used. These mounts force the engine through an elastomer damping element, which creates a low-pass filter.High-frequency components in such an induced excitation are significantly reduced and dissipated. Low-frequency components lead to a clearly measurable displacement of a connection point of the power unit (or a power unit-side bearing element) relative to a connection point of the body (or a support element-side bearing element). The design is usually such that an increasingly disproportionate counterforce is generated with increasing displacement.

[0003] However, in the field of purely or hybrid electric motor vehicles, such a design is fraught with difficulties. In response to a torque change request, an electric traction motor provides the target torque requested by the torque change request much more quickly (within the tens of milliseconds) than an internal combustion engine (several hundred milliseconds, just under a second). This means that these short-term, high torque jumps become acoustically noticeable in electric traction motors - especially in particularly powerful ones. Essentially, the forces generated between the two bearing points / bearing elements are so high for a short time that the damping element arranged between them cannot fully elastically absorb the resulting bearing impulse, and the bearing points / bearing elements collide or strike each other inelastically.Such a bearing shock or impact is audibly perceptible to occupants in the vehicle interior and is interpreted as disturbing and / or as a fault noise. This problem could be addressed by using innovative elastomer compounds, damping element designs, and / or significantly larger bearings to fully elastically absorb displacement. However, installation space in motor vehicles is always limited due to packaging constraints, which is why these solutions are not very effective. Furthermore, larger and therefore heavier bearings contradict the aim of particularly lightweight motor vehicles. It is clear that a conflict of objectives currently exists in which the requirements for particularly light and compact assembly mounts and the acoustic inconspicuousness of the assembly mounts - in particular the avoidance of bearing shock - compete with each other.

[0004] US 2023 / 0 116 610 A1 discloses a control system for controlling a regenerative braking system of an electrically powered motor vehicle. During regenerative braking, the response behavior of an electric drive motor of the motor vehicle is adjusted depending on a set driving mode and the number of passengers in the vehicle's interior.

[0005] Furthermore, DE 11 2012 004 458 T5 discloses a control device that can achieve compatibility between a torque response that coincides with a driver's acceleration request and a gear backlash reduction effect. A vehicle controller includes a torque change amount limiting control section configured to limit a torque increase amount per unit time of an engine driven based on an engine torque command to correspond to an accelerator manipulated variable when an accelerator stroke sensor detects that an accelerator pedal operation state has changed from a non-operated state to an operated state and the engine has switched from a braking torque to a driving torque.

[0006] Furthermore, EP 3 031 662 A1 proposes an electric vehicle control device and an electric vehicle control method capable of appropriately suppressing vibration. When a motor configured to generate torque for braking or driving a drive wheel is controlled based on a torque command value based on an accelerator pedal operation or a brake operation by a driver and a torque command value for vibration suppression control for suppressing a vibration component caused by resonance of the vehicle, a torque command value for the vibration suppression control is limited based on a state of the drive wheel during travel.

[0007] The object of the present invention is to prevent a knocking of a bearing of the electrical machine caused by a torque change of an electrical machine.

[0008] This problem is solved by the subject matter of the independent claims. Further possible embodiments of the invention are disclosed in the subclaims, the description, and the figures. Features, advantages, and possible embodiments presented in the description for one of the subject matter of the independent claims are to be regarded, across categories and embodiments, at least analogously as features, advantages, and possible embodiments of the respective subject matter of the other independent claims, as well as any possible combination of the subject matter of the independent claims, optionally in conjunction with one or more of the subclaims.

[0009] According to the invention, a method for operating an electric traction machine of a motor vehicle and a control device for the electric traction machine configured to carry out the method are proposed. Furthermore, the invention proposes a control device which is designed to control the electric traction machine and is configured to carry out the method. In its intended installation position, the control device forms a component of an electric traction machine, which is also the subject of the present invention. A further subject of the invention is formed by a motor vehicle which has the electric traction machine according to the invention. Accordingly, the motor vehicle is a purely or hybrid electric motor vehicle.

[0010] In the method for operating the electric traction machine, a bearing impulse limit is specified for a bearing arrangement by means of which the traction machine is mounted on a support element of the motor vehicle. The bearing impulse limit is characterized in that a collision or impact between a machine-side bearing element of the bearing arrangement and a support-element-side bearing element of the bearing arrangement is prevented if the machine-side bearing element is moved relative to the support-element-side bearing element with a bearing impulse that has a maximum of the bearing impulse limit. The bearing arrangement has one or two or more bearings, wherein the traction machine is mounted on the support element of the motor vehicle by means of the respective bearing.In addition, each bearing has a support-side bearing element and a machine-side bearing element, which are coupled to each other via a reversibly elastic damping element, which may be made of an elastomer, for example. Although only one of the bearings is discussed here, it should be understood that the entire description applies to the other bearings in the bearing arrangement.

[0011] In the method, before the start of an actual torque change, it is determined whether changing a current torque provided by the traction machine to a target torque with a predetermined, first torque gradient would cause a first bearing pulse having a first bearing pulse magnitude greater than the bearing pulse limit. In other words, the pending or desired torque change is not actually started immediately, but is first calculated or simulated to determine whether a bearing shock would occur due to the desired torque change. For example, a torque request signal is sent to the control device, which characterizes a request to change the current torque to the target torque.The torque request signal is generated and delivered, for example, based on an accelerator pedal position, a brake pedal position, a control signal from a cruise control system, a control signal from a driver assistance system, a control signal from a control unit for operating the motor vehicle in a partially or fully autonomous driving mode, etc. The target torque can be higher than the current torque, for example, for speed-increasing acceleration, or lower than the current torque, for example, for speed-reducing acceleration or braking and / or for recuperation operation of the traction motor.

[0012] Using a computing unit, which may be a hardware and / or software component of the control device, it is then determined on the basis of the specified bearing impulse limit value - initially without actually starting and executing the torque change - whether the impending change from the current torque to the target torque would, without further measures, result in the bearing elements colliding with one another in an undesirable manner. This determination is carried out repeatedly, for example, as long as the traction machine is operated in a motor and / or generator mode and / or at a determination cycle interval of 1 ms (milliseconds) to 100 ms, in particular up to 10 ms. It can be provided that the determination is paused while a torque change is being executed and resumed after / when the target torque is reached.

[0013] If the first bearing pulse magnitude is greater than the bearing pulse limit—i.e., if it has been determined that the bearing elements would collide—the traction machine is controlled to execute a change start step at the beginning of changing the current torque. This step involves changing the current torque with a second torque gradient that causes a second bearing pulse whose second bearing pulse magnitude is at most as large as the bearing pulse limit. In this way, collisions between the bearing elements are reliably prevented without requiring any design changes to the bearing arrangement. Therefore, for example, particularly simple, particularly compact and lightweight bearings can be used to support the electric traction machine. This is both economically and ecologically advantageous.At the same time, vehicle occupants do not hear any noise that could be interpreted as disturbing and / or as a fault noise by the bearing arrangement when the torque changes. In other words, a requested torque change or a requested torque jump is modeled in such a way that any acoustic abnormalities are avoided. The basic idea here is to deliberately operate the traction motor with a lower torque gradient in the millisecond range, giving the bearing arrangement more time to elastically absorb the bearing impulse caused by the torque change and generate a corresponding counterforce. In doing so, it is accepted that during acceleration - for example, when a vehicle driver presses or continues to press the accelerator pedal (so-called tip-in) - a lower positive torque than requested is delivered for a few milliseconds.Likewise, during braking or recuperation—for example, when the driver releases the accelerator pedal (so-called tip-out)—a lower negative torque than requested is delivered for a few milliseconds. However, both are unproblematic, since such short reductions in tractive or deceleration force, in the range of 100 ms, are barely perceptible to humans and, secondly, are not resolved in modern multi-speed transmissions.

[0014] If it is / has been determined that the first bearing impulse amount is equal to or less than the bearing impulse limit amount - that is, a collision of the bearing elements is not expected due to the upcoming torque change - the traction machine can be controlled to change the current torque in such a way that the torque is changed to the target torque with the first torque gradient, in particular in a single change step.

[0015] Another possible embodiment provides that—if it is determined that the first bearing pulse magnitude is greater than the bearing pulse limit magnitude—the traction machine is controlled in a first torque change mode to further change the torque after the change start step to execute a change step in which the torque is changed with the second torque gradient, i.e., with the second bearing pulse or the second bearing pulse magnitude, wherein the change step is executed repeatedly until the target torque is reached. This allows even large torque differences or jumps to be executed without bearing shocks, up to a torque difference that is approximately 1.8 times the nominal torque of the traction machine.This is relevant, for example, for a situation in which the traction motor is driven as a generator with full recuperation power (approximately -0.8 times the nominal torque can be used for recuperation), and based on this, a maximum acceleration request is entered (plus 1 times the nominal torque is requested). The traction motor can therefore be switched to the first torque change mode, for example, based on a user input. It is conceivable that the first torque change mode is automatically activated in conjunction with the activation of a specific driving mode of the vehicle, for example, when the driver activates a comfort or eco mode.

[0016] In a further possible embodiment, it is provided that the traction machine is controlled in a second torque change mode, different from the first torque change mode, for further changing the torque after the change start step to execute a bearing seating step, provided that it is / has been determined that the first bearing pulse amount is greater than the bearing pulse limit amount. During the bearing seating step, the torque is changed with a third torque gradient, whereby the machine-side bearing element is applied to the support-element-side bearing element with a bearing seating pulse. The bearing seating pulse has a bearing seating pulse amount that is characterized in that, when the machine-side bearing element is applied to the support-element-side bearing element, a noise perceptible by a human occupant in the interior of the motor vehicle is avoided.The bearing contact impulse amount is greater than the second bearing impulse amount and smaller than the first bearing impulse amount and is dimensioned such that the machine-side bearing element is applied gently and smoothly to the support-element-side bearing element without the occupants of the vehicle perceiving any noise emanating from the bearing arrangement, in particular without any perceptible noise being generated when the bearing elements come into contact. Advantageously, only a brief intervention in the torque modeling or provision takes place here if a bearing impact is to be expected. The traction machine can therefore be switched to the second torque change mode, for example based on a user input. The second torque change mode can be automatically activated in conjunction with the activation of another specific driving mode of the vehicle, for example when activating a sport mode.

[0017] In a possible further development, the traction machine is controlled after the bearing installation step to execute a single further change step, in which the torque provided by the traction machine after the bearing installation step is changed to the target torque using a fourth torque gradient in a single change step. The fourth torque gradient causes a fourth bearing pulse whose fourth bearing pulse magnitude is equal to or greater than the bearing installation pulse magnitude. It can be provided that the fourth bearing pulse magnitude is equal to or greater than the second bearing pulse magnitude, in particular equal to or greater than the bearing pulse limit magnitude. In any case, the machine-side bearing element remains applied to the support-element-side bearing element during the single further change step. Thus, despite the particularly rapid torque change, no noise is generated that is audibly perceptible to the occupants.

[0018] According to a further embodiment, the second bearing impulse amount is specified and / or adjusted and / or changed by a user input. In other words, a passenger of the motor vehicle, in particular the driver, can influence the amount by which the second bearing impulse amount is reduced compared to the bearing impulse limit. If, for example, the driver desires particularly comfortable driving behavior, they can significantly reduce the second bearing impulse amount compared to the bearing impulse limit. If, on the other hand, they desire sporty driving behavior, they can select the second bearing impulse amount so that it is particularly close to the bearing impulse limit.The selection of the extent by which the second bearing impulse amount is reduced compared to the bearing impulse limit amount can be made, for example, by means of an input from the driver on an input device of the motor vehicle, for example by means of a vehicle infotainment system, a driving mode switch, etc. In this way, the driver's wishes for a specific, individually adapted driving behavior of the motor vehicle are taken into account to a special degree.

[0019] According to another possible embodiment, a current damping element temperature of the elastic damping element of the bearing arrangement, by means of which the bearing elements are coupled to one another, is determined. Furthermore, the bearing impulse limit and / or the bearing contact impulse are / is specified based on the bearing temperature. Thus, it is not only possible—as is generally conceivable or conceivable across all embodiments—to specify the bearing impulse limit and / or the bearing contact impulse based on design parameters of the bearing arrangement or the damping element, but alternatively or additionally depending on the current temperature of the damping element. Since material and damping properties are temperature-dependent, the damping element temperature has a significant influence on whether a bearing shock would result at a given speed difference by which the current torque is to be changed.Thus, a bearing shock can be prevented particularly reliably by determining and specifying the bearing impulse limit and / or the bearing contact impulse based on the current damping element temperature of the elastic damping element. This means that the first bearing impulse, the second bearing impulse, the bearing contact impulse, and / or the fourth bearing impulse are determined based on the current damping element temperature. This results in a damping element temperature-dependent torque model for changing the torque to the target torque.

[0020] According to a possible further development, the current damping element temperature is determined by determining a damping element temperature change caused inside the damping element by its deformation when the machine-side bearing element moves, and adding this change to the initial temperature of the damping element. The damping element is heated by flexing (i.e., by the deformation work performed on / in the damping element material due to one of the bearing pulses). It is then determined—for example, using the control device—to what extent the damping element has heated up from the initial temperature due to previous torque changes. This is advantageous in that damping element temperature-dependent torque modeling for changing the torque does not require continuous sensory monitoring of the damping element temperature.

[0021] In this context, another possible embodiment provides for the initial temperature of the damping element to be determined based on a temperature detected away from the bearing assembly. For example, the temperature away from the bearing assembly, for example an ambient temperature, can be detected using a temperature sensor external to the bearing assembly, such as an ambient temperature sensor of the motor vehicle. The initial temperature of the damping element can then be determined based on the detected temperature. This eliminates the need to provide a separate temperature sensor for the bearing assembly or to integrate such a temperature sensor into the bearing assembly.Based on the recorded temperature, particularly the ambient temperature, and the most recently measured damping element temperature, the temperature of the damping element can be determined over time, since the relevant data (thermal conductivity of air and the damping element, etc.) are known. Because the bearing assembly is designed without a temperature sensor, it is particularly easy to manufacture. This supports the advantage of being able to use particularly simply constructed, particularly compact and lightweight bearings to support the electric traction motor.

[0022] Regardless of whether the output temperature of the damping element is determined by means of a temperature sensor internal to the bearing assembly, by means of a temperature sensor external to the bearing assembly, or computationally based on the temperature external to the bearing assembly, a further possible embodiment provides that the output temperature of the damping element is determined once when the traction machine switches from its deactivated state to its activated state. Until the traction machine switches to its deactivated state, the output temperature of the damping element is not determined again or not re-determined. Alternatively, the output temperature of the damping element can be determined or recorded repeatedly during the activated state of the traction machine and / or after a certain number of torque changes, in particular after each torque change.

[0023] Further features of the invention may emerge 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 description of the figures and / or in the figures alone, can be used not only in the respective combinations specified, but also in other combinations or on their own, without departing from the scope of the invention.

[0024] The drawing shows in the only figure (labelled Fig. 1) to illustrate a possible embodiment of a method for operating an electric traction machine of a motor vehicle, a corresponding flow chart. Other embodiments of the method (not shown) may have more or fewer steps than those described below and / or a different order of the steps. The following description also relates to a control device configured to carry out the method, as well as to an electric machine having the control device, which is designed here as an electric traction machine, and to a motor vehicle having the electric traction machine. The motor vehicle has a bearing arrangement by means of which the traction machine is mounted on a supporting element of the motor vehicle. The supporting element is, for example, a supporting frame or a self-supporting body of the motor vehicle.The bearing arrangement comprises one or more bearings, wherein the respective bearing has a support element side and a machine side bearing element, which are coupled to one another via a reversibly elastic damping element.

[0025] In the present example, in step S1, a current damping element temperature of the elastic damping element of the bearing assembly, by means of which the bearing elements are coupled to one another, is determined. For this purpose, for example, an initial temperature of the damping element is determined when the traction motor switches from its deactivated state to its activated state. In this case, the initial temperature of the damping element is determined based on a temperature detected away from the bearing assembly, namely by means of an ambient temperature sensor of the motor vehicle external to the bearing assembly. The initial temperature of the damping element is deduced from the ambient temperature detected by the sensor. This means that in the present example, the bearing assembly does not have its own temperature sensor; instead, the ambient temperature sensor already installed in the motor vehicle is used to determine the initial temperature.

[0026] In a further step S2, a bearing impulse limit is then specified for the bearing arrangement or for the bearing(s) – here based on the current damping element temperature or initial temperature. The bearing impulse limit is characterized by the fact that the machine-side bearing element and the support-element-side bearing element do not collide or strike each other if the machine-side bearing element is moved relative to the support-element-side bearing element with a bearing impulse that has a maximum of the bearing impulse limit.

[0027] In step S3, a torque request signal is sent to the control device, which characterizes a request to change the torque currently provided by the traction motor to a target torque. The torque request signal is generated and delivered, for example, based on an accelerator pedal position, a brake pedal position, a control signal from a cruise control system, a control signal from a driver assistance system, a control signal from a control unit for operating the motor vehicle in a partially or fully autonomous driving mode, etc.

[0028] In step S4, a computing unit, which may be a hardware and / or software component of the control device, then determines, based on the predefined bearing impulse limit value—without actually initiating the torque change—whether the impending change from the current torque to the target torque would cause the bearing elements to collide in an undesirable manner. In this case, this determination is performed repeatedly as long as the traction machine is operating in a motor and / or generator mode and / or at a determination cycle interval of 1 ms to 10 ms.If it is determined that collision of the bearing elements is not expected due to the upcoming torque change, the traction machine is controlled to change the current torque in such a way that the torque is changed to the target torque with the first torque gradient, in particular in a single change step S5. The actual achievement of the target torque is shown in . Fig. 1 designated S6.

[0029] If, however, it is determined in step S4 that said collision of the bearing elements would occur, the traction machine is controlled to execute a change start step S7 at the beginning of changing the current torque. In this step, the current torque is changed with a second torque gradient that causes a second bearing pulse whose second bearing pulse magnitude is at most as large as the bearing pulse limit magnitude. This prevents the bearing elements from colliding.

[0030] In a step S8, it is determined whether the traction machine is operating in a first torque change mode M1 or in a second torque change mode M2. In the first torque change mode M1, the traction machine is controlled to further change the torque after the change start step S7 by executing a change step S9, in which the torque is changed using the second torque gradient. The change step S9 is executed repeatedly until the target torque is reached. In this example, this is checked in a step S10, which is followed by the actual achievement S6 of the target torque or the actual provision of the target torque by the traction machine.

[0031] If it is detected in step S8 that the traction machine is being operated in the second torque change mode M2, it is controlled to further change the torque after the change start step S7 by executing a bearing seating step S11, in which the torque is changed with a third torque gradient, whereby the machine-side bearing element is gently applied to the support-element-side bearing element with a bearing seating pulse. The bearing seating pulse has a bearing seating pulse amount that is greater than the second bearing pulse amount and smaller than the first bearing pulse amount and is characterized in that when the machine-side bearing element is applied to the support-element-side bearing element, there is no noise that can be perceived by a human occupant in the interior of the motor vehicle. There is therefore only a brief intervention in the torque modeling or-provision if a bearing shock is to be expected, whereby occupants of the motor vehicle do not perceive any noise emanating from the bearing arrangement. In the second torque change mode M2, the traction machine is controlled after the bearing fitting step to carry out a single further change step S12, by means of which the torque provided by the traction machine after the bearing fitting step S11 is changed in one step to the target torque using a fourth torque gradient. The fourth torque gradient causes a fourth bearing pulse, the fourth bearing pulse amount of which is equal to or greater than the bearing fitting pulse amount. It can be provided that the fourth bearing pulse amount is equal to or greater than the second bearing pulse amount, in particular equal to or greater than the bearing pulse limit amount. In any case, the machine-side bearing element remains in contact with the support-element-side bearing element during the single further change step S12.

[0032] In the present example, the second bearing impulse amount is specified and / or adjusted and / or changed by a user input. In other words, the driver of the motor vehicle influences the extent by which the second bearing impulse amount is reduced compared to the bearing impulse limit. If, for example, the driver desires particularly comfortable driving behavior, they can reduce the second bearing impulse amount particularly significantly compared to the bearing impulse limit. If, on the other hand, they desire sporty driving behavior, they can select the second bearing impulse amount so that it is particularly close to the bearing impulse limit. The extent by which the second bearing impulse amount is reduced compared to the bearing impulse limit can be selected, for example, by means of a driver input on an input device of the motor vehicle, for example, via a vehicle infotainment system, a driving mode switch, etc.

[0033] According to the exemplary embodiment described here, the current damping element temperature is determined by determining a damping element temperature change caused inside the damping element by its deformation during movement of the machine-side bearing element, and adding this change to the initial temperature of the damping element. This is because the damping element is heated by flexing it. It is then determined—for example, using the control device—to what extent the damping element has heated up from the initial temperature due to torque changes that have already occurred. Furthermore, the present invention provides that the initial temperature of the damping element is determined only once when the traction machine switches from its deactivated state to its activated state, and is not determined again until the traction machine switches to its deactivated state.

[0034] The method, the control device, the traction machine, and the motor vehicle demonstrate a respective possibility for preventing knocking of the bearing of the electrical machine caused by a torque change. It is particularly noteworthy that known bearing components, in particular already developed industry standard parts, can be used, thus avoiding more expensive, risky new developments. List of reference symbols S1 to S12 process step M1 first torque change mode M2 second torque change mode QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] US 2023 / 0 116 610 A1

[0004] DE 11 2012 004 458 T5

[0005] EP 3 031 662 A1

[0006]

Claims

[1] Method for operating an electric traction machine of a motor vehicle, wherein - for a bearing arrangement by means of which the traction machine is mounted on a support element of the motor vehicle, a bearing impulse limit value is specified (S2), which is characterized in that a collision between a machine-side bearing element and a support element-side bearing element of the bearing arrangement is avoided if the machine-side bearing element is moved in relation to the support element-side bearing element with a bearing impulse that has at most the bearing impulse limit value, - before the start of an actual torque change, it is determined whether changing a current torque provided by the traction machine to a target torque (S6) with a predetermined first torque gradient would cause a first bearing pulse having a first bearing pulse amount that is greater than the bearing pulse limit amount (S4), and, - if the first bearing pulse amount is greater than the bearing pulse limit amount, the traction machine is controlled at the beginning of changing the current torque to execute a change start step (S7) in which the current torque is changed with a second torque gradient which causes a second bearing pulse whose second bearing pulse amount is at most as large as the bearing pulse limit amount. [2] Method according to claim 1, characterized bythat, if it is determined that the first bearing pulse amount is greater than the bearing pulse limit amount, the traction machine is controlled in a first torque change mode (M1) for further changing the torque after the change start step (S7) to execute a change step (S9) in which the torque is changed with the second torque gradient, wherein the change step (S9) is executed (S10) until the target torque is reached (S6). [3] Method according to claim 1 or 2, characterized byin that if it is determined that the first bearing pulse amount is greater than the bearing pulse limit amount, the traction machine is controlled in a second torque change mode (M2) for further changing the torque after the change start step (S7) to carry out a bearing seating step (S11) in which the torque is changed with a third torque gradient, whereby the machine-side bearing element is applied to the support-element-side bearing element with a bearing seating pulse, wherein a bearing seating pulse amount of the bearing seating pulse is characterized in that when the machine-side bearing element is applied to the support-element-side bearing element, a noise perceptible by a human occupant in an interior of the motor vehicle is omitted. [4] Method according to claim 3, characterized byin that the traction machine is controlled after the bearing placement step (S11) to carry out a single further change step (S12), in which the torque which the traction machine provides after the bearing placement step (S11) is changed in one step to the target torque with a fourth torque gradient (S6), wherein the fourth torque gradient causes a fourth bearing pulse whose fourth bearing pulse amount is equal to or greater than the bearing placement pulse amount, wherein during the single further change step (S12) the machine-side bearing element remains applied to the support-element-side bearing element. [5] Method according to one of the preceding claims, characterized by that the second bearing pulse amount is specified and / or set and / or changed by a user input. [6] Method according to one of the preceding claims, characterized bythat a current damping element temperature of an elastic damping element of the bearing arrangement, by means of which the bearing elements are coupled to one another, is determined, and the bearing impulse limit amount is specified based on the bearing temperature. [7] Method according to claim 6, characterized by that the current damping element temperature is determined by determining a damping element temperature change caused inside the damping element by its deformation when the machine-side bearing element moves, and adding it to an initial temperature of the damping element. [8] Method according to claim 7, characterized by that the output temperature of the damping element is determined once when the traction machine is switched from its deactivation state to its activation state and is not determined again until the traction machine is switched to its deactivation state. [9] Control device for an electric traction machine for a motor vehicle, wherein the control device is configured to carry out the method according to one of the preceding claims. [10] Electric traction machine with the control device according to claim 9. [11] Motor vehicle comprising the electric traction machine according to claim 10.

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