Method and system for adjusting one or both drive shafts with two electric motors

Abstract

The present invention relates to a method (100) for adjusting one or two electric drive shafts (1a, 1b) of a vehicle having electric motors (EM1, EM2), wherein the electric motors are connected to output terminals (2, 2a, 2b) via respective power transmission paths (3, 4), the method comprising the following steps: determining (101a) the rotational speed and torque values ​​of at least one mechanical component (5) loaded on the power transmission paths (3, 4) and / or the electric motors (EM1, EM2); identifying the damage state value of at least one mechanical component (5) due to a damage component within a predetermined time; and adjusting (107) the electric drive shafts (1a, 1b) taking into account the damage state of the at least one mechanical component (5).

Description

Technical Field

[0001] The present invention relates to a method and system for adjusting two electrically driven shafts of a vehicle, each having a motor, wherein a first motor is connected to a first output terminal via at least one first power transmission path and a second motor is connected to a second output terminal via at least one second power transmission path; or to a method and system for adjusting an electrically driven shaft having two motors that jointly drive an output terminal, wherein a first motor is connected to the output terminal via at least one first power transmission path and a second motor is connected to the output terminal via at least one second power transmission path. Background Technology

[0002] A series of drive systems and an electric shaft (i.e., the E-axis) driven by two electric motors are known from the prior art.

[0003] For example, document DE 10 2011 121 819 A1 discloses a vehicle drive system with two drive motors, each drive motor being mechanically connected to and acting on a corresponding sub-transmission. The drive motors are designed as electric drive motors and directly mechanically connected to their respective sub-transmissions, and can operate individually or jointly.

[0004] Document EP 2 450 597 A1 discloses a control device and method for an electric drive system in an electric vehicle with two motors. The purpose of this control device and method is to achieve uninterrupted power shifting.

[0005] This type of drive system can be controlled based on efficiency (see "...)" Shifting strategy and optimization for multi-mode E-axles (F. Bayer, cti Symposium, Berlin, 2020)). Summary of the Invention

[0006] The objective of this invention is to improve the long-term reliability or make it more predictable of electric drive shafts with two motors. In particular, the objective is to extend the service life of key components of the electric drive shaft.

[0007] This task is accomplished using the method and system according to the invention. Advantageous designs are claimed in this invention.

[0008] This invention relates to a method for adjusting two electrically driven shafts of a vehicle, each having a motor, wherein a first motor is connected to a first output terminal via at least one first power transmission path and a second motor is connected to a second output terminal via at least one second power transmission path; or to a method for adjusting an electrically driven shaft having two motors that jointly drive an output terminal, wherein a first motor is connected to the output terminal via at least one first power transmission path and a second motor is connected to the output terminal via at least one second power transmission path. The method comprises the following operational steps:

[0009] Determine the rotational speed and torque value applied to at least one mechanical component of the power transmission path and / or the motor;

[0010] Based on the applied rotational speed and applied torque, determine the damage component value associated with the at least one mechanical component and determine the damage state value of the at least one mechanical component due to the damage component within a predetermined time; and

[0011] Considering the damage state or relative damage state of the at least one mechanical component, adjust the two electric drive shafts if there are two electric drive shafts, or adjust the electric drive shaft if there is only one electric drive shaft.

[0012] An electric motor refers to a motor that, in principle, can operate as an engine or generator. The mechanical components used in this invention are preferably gears or bearings.

[0013] The damage component value in the context of this invention refers to the degree of damage to a component due to its current operation. Preferably, in the case of mechanical components, the damage component at a given moment is determined by the torque and rotational speed of the mechanical component applied to it at that moment. In the case of electrical components, the temperature of the electrical component is preferably taken into consideration when determining the damage component value.

[0014] The damage state value in this invention refers to the sum of damage components that have occurred since the component was put into use. In this case, the time share of each component's operation is also considered accordingly.

[0015] If a component reaches the maximum recommended damage state for that component, it has reached the failure probability that should not be exceeded. The component should not exceed the maximum recommended damage state when it reaches its expected service life. If the maximum recommended damage state is observed throughout the entire expected service life and uniform damage with respect to time is assumed, then there exists a maximum amortized damage state for each time point.

[0016] The relative damage state value in the sense of this invention is the ratio of the current damage state to the maximum shared damage state at that moment, and in particular the quotient of the two.

[0017] According to the present invention, the connection between the electric motor and the output terminal, which consists of a single power transmission path, can also be equipped with a separating element such as a clutch, so that the connection can be temporarily separated.

[0018] The two electric motors are preferably connected to their respective first or second output terminals via multi-speed gearboxes. At each output terminal, power and torque are input from their respective power transmission paths. The power or torque distribution between the power transmission paths can be freely selected and varied within defined limits in this arrangement without requiring maximum power.

[0019] The present invention is based on the concept that the damage state of mechanical components is taken into account when adjusting the electric drive shaft.

[0020] If a certain operating point of the electric drive shaft is required, defined by the output speed and output torque, then there are different possibilities or degrees of freedom for the operating strategy to achieve the operating point.

[0021] On the one hand, if the power delivery path has a multi-speed transmission, gears can be selected in each transmission. However, it is important to note that only the following gear combinations are allowed: neither motor is above its maximum RPM. If one power path is disconnected by means of a transmission, for example, by engaging neutral, then the other power delivery path should be able to provide full power; that is, the second motor should be able to generate all the required torque. For each possible gear combination, the torque distribution between the two motors or the power delivery path is the second degree of freedom, which must be determined in the operating strategy.

[0022] In this case, the sum of the torques of the two motors should be weighted and correspond to the required output torque with respect to their respective gear ratios. This means that the torque at one motor can be freely chosen within a range in which the torque obtained at the other motor does not exceed its maximum permissible torque. Therefore, the smaller the required output torque on the electric drive shaft, the greater the leeway in selecting the torques at these motors.

[0023] According to the present invention, the damage state that has occurred to date can be monitored for each relevant mechanical component at its current moment. The damage state is determined by accumulating the damage components based on the damage components generated since the component was put into use, taking into account the time fraction. The damage component at a given moment is further calculated based on the torque and revolutions applied at that moment. This means that the current damage state can be determined from the damage state at an earlier moment by adding the damage components generated during that period. The damage components are calculated from the component revolutions and the torque applied to the mechanical component at their respective moments. The identified damage state values ​​are not only related to adjustments in operating strategies, but damage state monitoring also helps determine whether components need to be replaced. Maintenance intervals can be adjusted in a vehicle-specific manner based on information about the respective damage states, and factory appointments and necessary matters (such as vehicle delivery to the end customer) can be scheduled in advance. In addition to cost savings, this also reduces the probability of drive system failures.

[0024] This service can be provided through control equipment, cloud services from vehicle manufacturers, or third-party vendors. These measures can be collectively referred to as "predictive maintenance."

[0025] Even in platooning scenarios, understanding the individual damage status of mechanical components can be useful. Drivers, or platoon operators, can then determine whether measures to protect components are necessary, or whether further focus on operational efficiency is warranted. Plague operators can also use information about component damage status to purposefully allocate vehicles to routes with higher or lower damage levels.

[0026] In this invention, it is specified that in the method, when there are two electric drive shafts, these electric drive shafts are adjusted in such a way, or when there is one electric drive shaft, the damage state or relative damage state of each different power transmission path is taken into consideration, and in particular, the damage state or relative damage state of each different power transmission path is balanced as much as possible.

[0027] Preferably, the system design is based on the electric drive shaft to define the maximum permissible or recommended damage state and expected service life for each component. Preferably, the component geometry (e.g., the gear width and radius of a cylindrical gear) is taken into account in this case. Damage exceeding the maximum recommended damage state will result in a higher probability of failure for the corresponding mechanical component. This electric drive shaft, or these electric drive shafts, can now be adjusted by means of the present invention so that the remaining service life, or the time until the maximum recommended damage state and / or failure probability of the corresponding mechanical component is reached, is relatively balanced. This results in an extended overall system service life, and on the other hand, a preferably reduced probability of failure and fewer factory visits for repair or replacement of components.

[0028] Furthermore, in another advantageous design of this method, in order to adjust these electric drive shafts when there are two electric drive shafts, or in order to adjust this electric drive shaft when there is only one electric drive shaft, the transmission ratio in at least one of the two power transmission paths or the power distribution between the two motors is adjusted such that the at least one mechanical component is not under load or is only under load in a prescribed manner. This also allows for uniform wear of the mechanical components.

[0029] The damage component of at least one mechanical component will be monitored. Preferably, the current damage state is compared with the maximum amortized damage state at this moment for the entire service life at predetermined ordered intervals, i.e., a relative damage state is determined. The intervals may be based on time, but may also be based on distance.

[0030] If the damage state or relative damage state of at least one mechanical component exceeds a critical value, then according to this design, a choice can be made between two measures. Preferably, both measures can also be employed:

[0031] The first measure corresponds to adjusting the transmission strategy in the power path of the relevant components. If the mechanical component is involved only in a few gears, an attempt will be made to avoid those gears, thereby reducing the time share of the mechanical component's effectiveness. If the mechanical component involves all gears of a multi-speed transmission and is placed in the drivetrain by the shifter on the drive side, then the highest gear ratio should be switched. A higher gear ratio shifts the load point at the corresponding motor to a higher RPM and lower torque, which generally results in a smaller damage component. Obviously, shifting is only feasible if the desired load point in the new gear can also be met without power loss, for example, without being limited by RPM or torque limitations at the motor. The power and torque distribution between the two power transmission paths remains unchanged in this case.

[0032] The second measure involves adjusting the power or torque distribution between power transmission paths. In a power transmission path with at least one associated mechanical component, power or torque is reduced at the expense of other power transmission paths. That is, other power transmission paths should provide correspondingly higher power or correspondingly larger torque. This measure reduces the damage component of all mechanical components in their respective associated power transmission paths. In other words, this measure is possible even when multiple components are involved in the power transmission path. Adjusting the torque distribution between two power transmission paths can be done indirectly, for example, by reducing the maximum possible torque or maximum possible power at the respective motors in the associated power transmission paths. This method then prioritizes adjusting the torque distribution, resulting in lower torque in the more severely damaged power transmission path. The selection of the ideal power distribution, considering the boundary conditions related to torque distribution, can then be based on efficiency. The reduction in torque can balance the remaining service life of the two power transmission paths.

[0033] Accordingly, the method has the following working steps in another advantageous design:

[0034] Check whether the current value of the damage state or relative damage state of at least one mechanical component is higher than a first limit value; and

[0035] If the value exceeds the first limit, the threshold for the torque provided by the first motor and / or the torque provided by the second motor is determined in particular based on the damage component caused by the provided torque, wherein the electric drive shafts are adjusted in consideration of the torque threshold when there are two electric drive shafts, or the electric drive shaft is adjusted in consideration of the torque threshold when there is one electric drive shaft.

[0036] The threshold value for the torque provided by the electric motor preferably represents the maximum torque at which the motor should operate. A low threshold reduces the time share of power required at the output that is met through a more severely damaged power delivery path. This results in at least one mechanical component being protected from damage exceeding a first limit value.

[0037] The threshold should preferably be observed by means of the measures described prior to at least one mechanical component.

[0038] Therefore, in another advantageous design of the method, in order to adjust these electric drive shafts when there are two electric drive shafts or in order to adjust this electric drive shaft when there is only one electric drive shaft, the transmission ratio of at least one of the two power transmission paths is adjusted such that the motor with the determined threshold can operate at different speeds in different operating modes, or the power distribution between the two motors is adjusted such that the motor with the determined threshold can provide or withstand less torque.

[0039] Damage to mechanical components depends on the torque applied to them. Therefore, the torque can be reduced by increasing the revolutions per revolution while maintaining the same power output, or by reducing the power output while maintaining the same revolutions per revolution, thereby reducing the damage component.

[0040] The preferred approach is to determine which of the described measures to adopt, taking into account their respective efficiencies.

[0041] In another advantageous design of this method, the damage state is determined as follows:

[0042]

[0043] or

[0044] ,

[0045] Where n is the number of revolutions and T is the torque. t is the time step, and p is a parameter representing the intensity of the damage component for at least one mechanical component, wherein parameter p is set for each mechanical component.

[0046] Therefore, in this design, the damage state is the accumulation of time-discrete damage components over a certain period of time. Preferably, the damage components of each vehicle component are collected throughout the entire life cycle, starting from the date the vehicle is put into use. In this way, the damage state of each component can be accurately predicted.

[0047] In another advantageous design, the method also includes the following working steps:

[0048] Determine the temperature value of at least one electrical component;

[0049] Based on the temperature value, a damage component value associated with at least one electrical component and a damage state value obtained according to this damage component within a predetermined time period are determined.

[0050] In the case of two electric drive shafts, these electric drive shafts are adjusted while considering the condition of damage to at least one electrical component, or in the case of one electric drive shaft.

[0051] In the case of electrical components such as motors or inverters, lifespan is significantly affected by component temperature. Overheating of electrical components shortens their lifespan and should be prevented as much as possible. By adaptively adjusting this regulation strategy, the probability of overheating of the motor or inverter is reduced, and the component's lifespan is extended. This requires monitoring the temperature at each component; for example, the motor and inverter should be equipped with temperature sensors. If the temperature at the motor or inverter exceeds a predetermined maximum temperature, the regulator can reduce the thermal load on that component by:

[0052] The power required by the electric drive shaft is initially provided through unrelated power paths. Power paths with excessively hot or overheated components only serve a secondary role, as they provide insufficient power. Power distribution then favors the cooler components. Smaller power losses occur at the overheated components, preventing further heating or leading to cooling.

[0053] If the power required by the electric drive shaft can be provided through only one power transmission path, then the power transmission path with the relevant components can be disconnected, perhaps upstream, via the transmission.

[0054] If one of the two measures has been taken and the components involved have reached an acceptable temperature range, these measures can be readjusted.

[0055] Furthermore, in another advantageous design, this method has the following working steps:

[0056] Check whether the damage status value or relative damage status value of the electrical components is higher than the second limit value;

[0057] If it exceeds the second limit value, the threshold for the power supplied by the first motor and / or the second motor is determined in particular based on the damage component caused by temperature, wherein, in the case of two electric drive shafts, these electric drive shafts are adjusted in consideration of the threshold for the power supplied, or in the case of one electric drive shaft.

[0058] By determining the threshold for the power supplied, the temperature-related damage component can be limited. This allows for the mitigation of accelerated damage before reaching a value suitable for their respective operating periods.

[0059] In another advantageous design, electrical components are cooled according to this temperature value. This prevents damage to components.

[0060] In another advantageous design, the method has the following working steps:

[0061] Provide a reference damage state for at least one mechanical component and / or at least one electrical component; and

[0062] A relative damage state is determined based on the determined damage state and a reference damage state, wherein a first limit value and / or a second limit value are defined with respect to the relative damage state.

[0063] From the design of vehicle components, the permissible damage component during the service life of each component and, consequently, the maximum permissible damage state after the expected service life has expired are generally known. The damage components that accumulate at a certain point in time and collectively form the damage state can be correlated with the maximum shared damage component at that time, i.e., the permissible damage state, and the relative damage state R can be determined in this way. Regarding the relative damage state R, measures can then be taken to adjust the damage components.

[0064] The optimal value of the relative damage state R can be interpreted as follows:

[0065] R>1:

[0066] If the component continues to be subjected to the same loads as before, it may not reach its expected service life. Component failure before the end of its expected service life is possible or highly probable.

[0067] R=1:

[0068] If the component continues to bear the load as it has so far, it is possible to reach the expected service life of the component.

[0069] R<1:

[0070] If the component continues to be subjected to the same loads as before, it is possible that it will exceed its expected service life if the usage remains unchanged. It is unlikely that the component will fail before the end of its expected service life.

[0071] Furthermore, in another advantageous design of the method, when adjusting the two motors, the efficiency of the electric drive shafts is considered either when there are two electric drive shafts or when there is only one electric drive shaft, wherein the paired operating points of the first and second motors are selected such that, under conditions that torque and / or power thresholds are met at at least one of the two motors, an operation with optimized efficiency occurs.

[0072] In another advantageous design of the method, the first and / or second motors may exceed this or these thresholds to buffer torque peaks and / or power peaks.

[0073] By flexibly using these thresholds, higher power or torque can be provided without having to design the component as it would be when continuously delivering that power. This results in a good trade-off between the generated power, system power capability, and its weight. Attached Figure Description

[0074] Other features and advantages are described below with reference to the figures. The figures are shown at least partially schematically:

[0075] Figure 1a An embodiment of an electrically driven shaft for a vehicle is shown;

[0076] Figure 1b An embodiment of a vehicle with two electrically driven shafts is shown;

[0077] Figure 2a A detailed diagram of the mechanical components of this first embodiment of an electric drive shaft is shown;

[0078] Figure 2b A detailed diagram of the mechanical components of a first embodiment of the two electrically driven shafts is shown.

[0079] Figure 3a A detailed diagram of the mechanical components of this second embodiment of the electric drive shaft is shown;

[0080] Figure 3b Detailed diagrams of the mechanical components of the second embodiment of the two electrically driven shafts are shown;

[0081] Figure 4 A block diagram illustrating an embodiment of a method for adjusting an electrically driven shaft;

[0082] Figure 5a The time curves of the damage state and the time curves of the associated maximum amortized damage state are shown in curve graphs.

[0083] Figure 5b The time curves of relative damage states are shown;

[0084] Figure 6 A graph showing different torque distributions between electric motors with a single electric drive shaft is shown.

[0085] Figure 7 An embodiment of a process for determining a threshold of torque provided by one of the electric motors is shown;

[0086] Figure 8 A flowchart is shown to illustrate the process for determining the torque distribution between two electric motors for an electric drive shaft.

[0087] Figure 9 Different graphs are shown related to an example of an adjustment strategy for an electric drive shaft;

[0088] Figure 10 An embodiment of a system for adjusting an electrically driven shaft with two motors is shown. Detailed Implementation

[0089] Figure 1a An embodiment of an electrically driven shaft 1 is shown. It is driven by two electric motors EM1 and EM2. Each electric motor EM1 and EM2 is connected to the actual shaft 2 in a torque-transmitting manner via a gearbox 3 and 4, or can be connected to the shaft if a clutch is available.

[0090] The mechanical arrangement is designed in such a way that two electric motors, EM1 and EM2, can simultaneously input power to shaft 2.

[0091] The power input to the shaft is preferably designed such that the two output torques of transmissions 3 and 4 are added together in shaft 2. This can be achieved, for example, through a cylindrical gear stage or a common differential.

[0092] In this case, the two transmissions 3 and 4 can be designed as simple cylindrical gear stages, i.e., single-speed transmissions, but they can also be designed as multi-speed transmissions with or without clutches.

[0093] Therefore, a first power path is formed from the first electric motor EM1 to the shaft 2 via the first transmission 3. A second power path is formed from the second electric motor EM2 to the shaft 2 via the second transmission 4.

[0094] Preferably, both transmissions 3 and 4 can disconnect their respective power transmission paths, for example, by disengaging the clutch or by shifting to neutral.

[0095] This allows shaft 2 to be driven by only one of the two motors EM1 and EM2. The two motors EM1 and EM2 are preferably powered separately via respective converters or inverters 12 and 13. Preferably, inverters 12 and 13 each include an adjustment unit that uses a so-called electric shaft adjuster 14. (EACU) The target torque for each motor EM1 and EM2 is set. The current loaded torque and current loaded speed of motors EM1 and EM2 are provided to the electric shaft adjuster 14.

[0096] Preferably, the rotation speeds of motors EM1 and EM2 are also measured by rotation speed sensors 15 and 16, respectively, and are available for use by the electric shaft adjuster 14.

[0097] The more accurately the electric shaft adjuster 14 identifies the current speed of the motors EM1 and EM2 and the torque applied to each power transmission path or related components, the more advantageous it is for adjustment strategies that take mechanical damage components into account.

[0098] The actual axle 2 drives the vehicle's wheels 17 and 18.

[0099] Figure 1b An embodiment of two electrically driven shafts 1a and 1b of the vehicle is shown. They are driven by two electric motors EM1 and EM2. Each electric motor EM1 and EM2 is connected to the actual shafts 2a and 2b via a transmission 3 and 4, respectively, to transmit torque, or may be connected to these shafts if a clutch is available.

[0100] With this mechanical arrangement, the two electric motors EM1 and EM2 can simultaneously input power to their respective connected shafts 2a and 2b.

[0101] In this case, the two transmissions 3 and 4 can be designed as simple cylindrical gear stages, i.e., single-speed transmissions, but they can also be designed as multi-speed transmissions with or without clutches.

[0102] Therefore, a first power path is formed from the first electric motor EM1 to the first shaft 2a via the first transmission 3. A second power path is formed from the second electric motor EM2 to the second shaft 2b via the second transmission 4.

[0103] Both transmissions 3 and 4 are preferably able to disconnect their respective power transmission paths, for example, by disengaging the clutch or by using neutral.

[0104] The two electric motors EM1 and EM2 are preferably powered by respective converters or inverters 12a and 12b. Preferably, inverters 12a and 12b each include an adjustment unit that uses a so-called electric shaft adjuster 14. (EACU)This is used to set the target torque for each motor EM1, EM2. The current loaded torque and current loaded speed of motors EM1, EM2 are available to the electric shaft adjuster 14.

[0105] Preferably, the rotational speeds of motors EM1 and EM2 are also measured by rotational speed sensors 15a and 15b, respectively, and are available for use by the electric shaft adjuster 14.

[0106] The more accurately the electric shaft adjuster 14 identifies the current speed of the motors EM1 and EM2 and the torque applied to each power transmission path or related components, the more advantageous it is for adjustment strategies that take mechanical damage components into account.

[0107] The actual axles 2a and 2b drive the vehicle's wheels 17a, 17b, 18a, and 18b.

[0108] Figure 2a A detailed view of a first embodiment of an electric drive shaft 1 is shown. This detailed view shows the respective gears and bearings of the power transmission path. These are also components that suffer the greatest mechanical damage during the operation of the electric drive shaft 1. The first transmission 3, which essentially forms the first power transmission path, preferably has a first cylindrical gear stage 8 and second cylindrical gear stages 9, 10. The second cylindrical gear stages 9, 10 are designed to be shiftable in this case, wherein selection can be made between two gears or between gear ratios in the form of a first gear ratio 9 and a second gear ratio 10.

[0109] The second transmission 4, which essentially forms the second power transmission path, also has two cylindrical gear stages 9 and 10, but cannot change the gear ratio. The two transmissions 3 and 4 preferably input power to a differential 11, which in turn drives the real shaft 2.

[0110] Figure 2b A detailed view of a first embodiment of the vehicle's first electric drive shaft 1a and second electric drive shaft 1b is shown. This detailed view shows the respective gears and bearings of the power transmission path. These are also components that suffer the greatest mechanical damage during the operation of the electric drive shafts 1a and 1b. The first transmission 3, which essentially forms the first power transmission path, preferably has a first cylindrical gear stage 8a and second cylindrical gear stages 9a and 10a. The second cylindrical gear stages 9a and 10a are designed to be shiftable in this case, wherein selection can be made between two gears or between gear ratios in the form of a first gear ratio 9a and a second gear ratio 10a.

[0111] The second transmission 4, which essentially forms the second power transmission path, also has two cylindrical gear stages 9b and 10b, but cannot change the gear ratio. The two transmissions 3 and 4 preferably input power to the differentials 11a and 11b respectively, and the differentials in turn drive the actual shafts 2a and 2b.

[0112] Figure 3a A detailed diagram of the mechanical components of a second embodiment of the electric drive shaft 1 is shown. This embodiment is essentially the same as that according to... Figure 2a The first embodiment is the same. However, unlike the first embodiment, the second transmission 4 is also designed to have a second transmission stage that can shift between two gear ratios. Furthermore, neutral between the first transmission 3 and the second transmission 4 can also be achieved using a clutch mechanism.

[0113] Figure 3b Detailed diagrams of the mechanical components of a second embodiment of the two electrically driven shafts 1a and 1b are shown. This embodiment is essentially the same as that according to... Figure 2b The first embodiment, which has two electrically driven shafts 1a and 1b, is the same. However, unlike the first embodiment, the second transmission 4 is also designed to have a second transmission stage capable of shifting between two gear ratios. Furthermore, neutral between the first transmission 3 and the second transmission 4 can be achieved using a clutch mechanism.

[0114] Figure 4 A block diagram showing an embodiment of a method 100 for adjusting an electric drive shaft 1 of two motors EM1 and EM2 that share a common output terminal 2.

[0115] This method monitors the service life associated with mechanical component damage in terms of gear selection and torque distribution between the two power delivery paths, and adaptively takes this into account in the operating strategy.

[0116] Damage caused by mechanical action is considered in the first step. Furthermore, the damage component caused by thermal load, particularly in electrical components, can also be considered in the operating strategy.

[0117] Therefore, in the first working step 101a), the rotational speed and torque values ​​applied to at least one mechanical component 5 in the power transmission path and the transmission path of the motor are determined. In particular, these values ​​are measured directly or indirectly by means of sensors. Such mechanical components 5 that apply torque are, in particular, bearings and gears.

[0118] In the second working step 102a), the damage component value associated with at least one mechanical component 5 is determined based on the applied rotational value and the applied torque value, and the damage state value of at least one mechanical component 5 due to the damage component within a predetermined time is determined.

[0119] Preferably, in the third working step 103a), the maximum shared damage state D for the at least one mechanical component and / or at least one electrical component is provided. max (t).

[0120] In the fourth working step 104a), based on the determined damage state D j (t) and the maximum shared damage state Dmax (t) determines the relative damage state R j (t), where the first limit value and / or the second limit value are defined in relation to the relative damage state.

[0121] Furthermore, in the fifth working step 105a), it is preferable to check whether the damage state value is higher than the first limit value.

[0122] In the sixth working step 106a), if the value is higher than the first limit value, it is preferable to determine a threshold for the torque provided by the first motor EM1 and / or the second motor EM2, in particular based on the damage component caused by the provided torque and / or based on the damage state, wherein the electric drive shaft is adjusted with consideration of the threshold for the power provided.

[0123] Finally, in the seventh working step 107, the electric drive shaft 1 is adjusted considering the damage state of at least one mechanical component 5.

[0124] Preferably, the electric drive shaft 1 is adjusted in this case such that the relative damage states and / or instantaneous damage components of different power transmission paths 3 and 4 are taken into account. More preferably, the adjustment is made such that the relative damage states of different power transmission paths are balanced as much as possible.

[0125] To adjust the electric drive shaft 1, there are essentially two alternative options: either adjust the transmission ratio in at least one of the two power transmission paths 3, 4 so that at least one mechanical component 5 is not under load or is under load in a specified manner; or adjust the power distribution between the two electric motors EM1, EM2 so that the mechanical component is also not under load or is under load only in a specified manner.

[0126] More preferably, in order to adjust the electric drive shaft, or to adjust the transmission ratio in at least one of the two power transmission paths such that the motors EM1 and EM2 with the threshold can operate at another, particularly higher, speed at another operating point, or the power distribution between the two motors is adjusted such that the motors EM1 and EM2 with the threshold can provide or withstand less torque.

[0127] In the second working step 102a), the damage state is preferably determined by the following formula:

[0128] ,

[0129] or

[0130] .

[0131] In this case, n is the number of revolutions, T is the torque, Δt is the time step, and p is a parameter representing the intensity of the damage component for at least one mechanical component 5. The parameter p should be set for each mechanical component 5.

[0132] like Figure 4 As shown (right branch), the method 100 for adjusting the electric shaft can also be performed in parallel with electrical components (not specifically shown). These electrical components are, for example, components of electric motors EM1, EM2 or inverters 12a, 12b.

[0133] The working steps in this case are basically similar to the description of determining the damage component values ​​associated with at least one mechanical component 5, especially bearings or gears.

[0134] Here, the temperature value of at least one electrical component is also determined in the first working step 101b).

[0135] In the second working step 102b), a damage component value associated with at least one electrical component and a damage state value derived from the damage component within a predetermined time are determined based on the temperature value.

[0136] In the third working step 103b), a reference damage state for at least one electrical component is also provided with regard to temperature.

[0137] In the fourth working step 104b), the relative damage state of the electrical component 7 is determined based on the determined damage state and the reference damage state, wherein the second limit value is defined with respect to the relative damage state.

[0138] In the fifth working step 105b), it is preferable to check whether the damage state value is higher than the second limit value.

[0139] In the sixth working step 106b), if the value is higher than the second limit, a threshold for the power supplied by the first motor EM1 and / or the second motor EM2 is determined, in particular, based on the damage component caused by temperature and / or based on the damage state, wherein the electric drive shaft is adjusted taking into account the threshold for the power supplied.

[0140] If thermal damage is taken into account, the electric drive shaft 1 is adjusted in the seventh working step 107 while considering damage to at least one electrical component.

[0141] As a supplement to or alternative to the seventh operating step 107, in this case, it can be specified in the eighth operating step 108 that at least one electrical component is cooled according to a temperature value. Therefore, there are two possibilities for reducing the load on the electrical component. One possibility is to reduce the power of the motor to which the associated electrical component is located. The second possibility is to cool the electrical component.

[0142] Additionally, where feasible in terms of power, one of the power transmission paths of the relevant electrical components can be disconnected via an upstream transmission (if it is shiftable).

[0143] Figure 5a The graph shows the damage state D as a function of time. (Dash line D) max (t) represents the maximum amortized damage state over time, where the maximum recommended damage state (dashed line: linearly increasing) is reached exactly at the end of the component's expected service life. Damage exceeding the maximum recommended damage state will result in a higher probability of failure. D... j (t) reflects the actual accumulated damage component of component 5 at time t, i.e., the damage state, that is, the damage state determined based on the actual load and the torque and revolutions of the component. Curve D j (t) is monotonically increasing. As shown in the curve, the actual damage state D j (t) From time t1 onwards, the damage state is higher than the maximum shared damage state D set for this time. max (t). By setting measures to reduce the damage component after time t1, curve D is generated. j (t) Flattening. Curve D j (t) can therefore be extended to curve D. max Below (t). At time t2, the curve of the actual damage state then drops to the maximum shared damage state D. max Below (t2). However, if no measures are taken during the time interval between t1 and t2, then curve D... i (t) will not flatten and will reach the maximum recommended damage state before the expected service life (like 20 years in the example). There is a higher probability of component 5 failure before the expected service life expires.

[0144] exist Figure 5a In this context, the expected service life is, for example, 20 years.

[0145] exist Figure 5b In the middle, the relative damage state R j (t) in the curve about Figure 5a The timeline is shown.

[0146] Relative damage state R j (t) Here, the actual damage state D at a certain time t is given. j (t) is obtained by dividing each by its maximum shared damage state.

[0147] The period between t1 and t2 is characterized by a relative damage state R greater than 1. This should be prevented to avoid premature component failure. Accordingly, the limit value R... inc and R decIt is best to be limited, in Figure 5b The dashed line indicates that measures are taken or revoked when the value exceeds or falls below the stated limit to reduce further damage. Therefore, when the limit value R, representing the maximum expected relative damage state, is exceeded... inc In such cases, measures should be taken or strengthened to reduce the damage component. R dec The following represents a relative damage state value; when this value is below, measures to reduce the damage component can be mitigated. Two limit values ​​R inc and R dec It is preferable to have a value less than R=1.

[0148] If the relative damage state R j If the value of (t) increases to a value greater than 1, a warning light can be activated, for example. This indicates that the load on the component has exceeded the average value at the current moment.

[0149] Damage state D max (t) is therefore the time-dependent limit of the damage state. This value is different for each component (j).

[0150] exist Figure 5b In this context, the value R=1 corresponds to this limit value.

[0151] Figure 6 The process is shown for determining the threshold for the torque or power supplied by the electric motor according to the damage state limit value.

[0152] In this case, j represents the relevant components.

[0153] Figure 6 The process for determining a threshold value for the torque provided by the first electric motor EM1 or the second electric motor EM2 is illustrated. This measure prevents overload of the mechanical components 5 and / or electrical components of the electric drive shaft. As previously described, this measure may be a threshold value for the torque to be provided by the first electric motor EM1 or the second electric motor EM2, or a shifting process that moves the operating point of the first electric motor EM1 or the second electric motor EM2 to a higher speed or completely disconnects the corresponding motor, or cooling of the mechanical components 5 and / or electrical components.

[0154] This process can be explained in relation to torque limiting. However, it is obvious to technicians that this process can also be applied to other measures.

[0155] In the subsequent process, T max This represents the maximum possible torque on motor EM1 or EM2 in the power path involved. If component j is one of the relevant components in the power path involved, then T... j This represents a proposed torque limiting measure based on the current relative damage state of component j. Ultimately, the torque limiting T is implemented on the electric motor.lim This will be based on the constraint proposal T of all relevant component j. j Therefore, T is applicable on the one hand. lim Less than or equal to T j On the other hand, T lim It is always less than or equal to T. max At the start of the process, i.e., t=0, there is no proposed torque limit T associated with any component j. j Therefore, at this moment, T applies to all components. j =T lim =T max That is, there is no active torque limitation due to any proposed torque limitation of component j, and if necessary, the two motors EM1 and EM2 can operate at their maximum torque T respectively. max run.

[0156] In the first process step, the current relative damage state R of all components j. j The query is being performed. Since no measures have been taken to limit the torque at this moment, proceed to the right branch of the block diagram. Now check the current relative damage state R. j Is it greater than the maximum expected relative damage state R? inc Under the maximum expected relative damage state, measures should be introduced or strengthened. If this is the case, a new measure related to the component should be identified; in the current case, this is a torque limiting proposal T. j However, if the relative damage state R j Less than the limit value R inc If not, no action will be taken. Regarding the torque limitation proposal for the component, T... j Therefore, it is also equal to the maximum possible torque T at the respective motors EM1 and EM2 driving their respective power transmission paths 3 and 4. max .

[0157] This inspection covers all components along power delivery paths 3 and 4. Active torque limiting T is used for the power delivery paths. lim Therefore, a minimum definite torque limit proposal T for component j is adjusted. j Then, the process starts from scratch again. This is because there is now a measure in place, namely, active torque limiting T. lim Therefore, the process proceeds to the left branch. Now, the current relative damage state R... j It is preferable to compare with three different limiting values. In this case, R inc As already explained, this is the maximum expected relative damage state, under which measures should be introduced or strengthened.

[0158] R decIt is a relative state of damage; when it does not exceed this level, mitigation measures can be taken.

[0159] R min It is a relative damage state; when it is below this level, no measures are needed.

[0160] In this case, the following relationship applies:

[0161] R inc >R dec >R min

[0162] If the current relative damage state R j Greater than R inc In this case, the measure should be strengthened, which means that the torque limit T should be reduced in torque-related situations. j The threshold.

[0163] If the current relative damage state R j Less than R min If so, the aforementioned measure can be cancelled with respect to the component. In this case, what applies to the component is the ability to provide the maximum torque T of each motor EM1, EM2. max .

[0164] In the current relative damage state R j Less than R dec But greater than R inc In certain situations, the respective measures can be mitigated. In torque-limited situations, this means the threshold can be lowered.

[0165] If the current relative damage state R j Less than R inc But greater than R dec Then the measures can remain unchanged with respect to component j.

[0166] This process is also repeated for all components j. Active torque limiting T lim Therefore, for each power transmission path 3, 4, adjustments are made such that they correspond to the respective thresholds of the strongest measures used for a component j in its respective power transmission path 3, 4. Regarding torque, this means the active torque limit T. lim Corresponding to the torque limit proposal T for all components j j The minimum value.

[0167] Figure 7 Two graphs are shown, plotting the motor characteristic curves for the first motor EM1 and the second motor EM2, respectively. In this case, the torque is plotted with respect to the motor speed.

[0168] Based on these two graphs, the torque distribution between the first motor EM1 and the second motor EM2 can be determined at predetermined power and predetermined speeds n1 and n2 at the two motors EM1 and EM2. In this case, there is an active torque limit T for the first motor EM1 or the first power transmission path 3 it serves. lim .

[0169] Accordingly, only the following torque distribution pairing can be selected, where the torque provided by the first motor EM1 is lower than T. lim Otherwise, it is best to choose the torque distribution in such a way that the efficiency of the electric drive shaft 1 is optimized.

[0170] Figure 8 This illustrates the process for selecting this torque distribution while considering the overall system efficiency.

[0171] The predetermined conditions for this process are the overall required load points at output terminals 2a and 2b and the possible active torque limit T in one or two power transfer paths 3 and 4. lim If there is a torque limit T lim Then, focusing on efficiency and considering active torque limiting T lim Torque distribution is determined under certain conditions. If no solution exists, torque distribution is determined with efficiency in mind, without considering torque limitations.

[0172] The same applies to T-type engines that do not have active torque limiting. lim hour.

[0173] Figure 9 Based on four graphs (a), (b), (c), and (d) showing torque varying over time, specific examples are illustrated. In this case, the method used is... Figure 8 Adjustment strategy. Figure 9 In this case, a and 9b represent the time-discrete torque provided by the first electric motor EM1.

[0174] and Figure 9 c and 9d represent the torque values ​​provided by the second electric motor EM2. Figure 9 In cases a and 9c, there is no active torque limitation T. lim And in Figure 9 There is a torque limit T for the first electric motor EM1 in b and 9d. lim .

[0175] If the torque required at the first motor EM1 is higher than the active torque limit T for the first motor EM1 or the first power transmission path 3 lim The required excess torque is as follows Figure 9As shown in b and 9d, the load is provided by the second motor EM2. It should provide a larger torque T at the indicated times t1, t2, and t3 so that the first motor EM1 can reduce the torque T it provides. This is no longer feasible at later times t4, t5, and t6 because the second motor EM2 has also reached its power or torque limit T. max In this situation, to provide the required torque, it is best to forgo torque redistribution and ignore the active torque limit T. lim .

[0176] Figure 10 A system 20 is shown for adjusting an electric drive shaft 1 having two motors EM1 and EM2.

[0177] This system 20 preferably includes a device 21, particularly a sensor, for determining the rotational and torque values ​​of at least one mechanical component 5 loaded on the power transmission paths 3, 4 and / or the motors EM1, EM2. Furthermore, this system 20 preferably includes a device 22 for determining a damage component value for at least one mechanical component 5 based on the loaded rotational and torque values, and for determining the damage state value of at least one mechanical component 5 due to the damage component within a predetermined time. This system 20 also preferably includes a device 23 for adjusting the electric drive shaft 1 considering the damage state of at least one mechanical component 5. Finally, the system includes a device for adjusting the two electric drive shafts when there are two electric drive shafts, or adjusting the electric drive shaft when there is only one electric drive shaft, taking into account the damage states or relative damage states of the different power transmission paths, particularly adjusting in such a way that the damage states or relative damage states of the different power transmission paths are balanced as much as possible.

[0178] The apparatus of this invention can be designed using hardware and / or software techniques, and particularly preferably comprises a digital processing unit, especially a microprocessor unit (CPU), and / or one or more programs or program modules, connected to a memory system and / or a bus system via data or signals. The CPU can be designed to process commands implemented in the form of a program stored in the memory system, acquire input signals from the data bus, and / or send output signals to the data bus. The memory system can have one or more, especially different, storage media, and particularly optical, magnetic, solid-state, and / or other non-volatile media. The program can be provided such that it can implement or execute the methods described herein, thereby enabling the CPU to perform the steps of the method.

[0179] System 20 preferably has other devices to carry out other working steps of method 100. More preferably, at least some of these devices, and in particular the entire system 20, are integrated into electric shaft adjuster 14.

[0180] It should be noted that these embodiments are merely examples and should in no way limit the scope of protection, application, or structure. Rather, those skilled in the art will be inspired by the foregoing description to implement at least one embodiment, in which a wide variety of changes can be made, particularly concerning the function and arrangement of the said components, without exceeding the scope of protection as derived from the claims and equivalent descriptions.

Claims

1. A method (100) for adjusting two electrically driven shafts (1a, 1b) of a vehicle, each having a motor (EM1, EM2), wherein, The first motor (EM1) is connected to the first output terminal (2a) through at least one first power transmission path (3), and the second motor (EM2) is connected to the second output terminal (2b) through at least one second power transmission path (4), or A method (100) for adjusting an electrically driven shaft (1) having two motors (EM1, EM2) that jointly drive an output terminal, wherein the first motor (EM1) is connected to the output terminal via at least one first power transmission path (3) and the second motor (EM2) is connected to the output terminal via at least one second power transmission path (4). The method has the following steps: Determine (101a) the rotational speed and torque value of at least one mechanical component (5) of the power transmission path (3, 4) and / or the motor (EM1, EM2); Based on the applied rotational value and the applied torque value, determine (102a) the damage component value associated with the at least one mechanical component (5), and determine the damage state value of the at least one mechanical component (5) due to the damage component within a predetermined time. Considering the damage state or relative damage state of the at least one mechanical component (5), adjust (107) the two electric drive shafts (1a, 1b) when there are two electric drive shafts (1a, 1b) or adjust the electric drive shaft (1) when there is one electric drive shaft (1). In the case of two electric drive shafts (1a, 1b), the two electric drive shafts (1a, 1b) are adjusted in such a way that, in the case of one electric drive shaft (1), the electric drive shaft (1) is adjusted in such a way that the damage state or relative damage state of each different power transmission path (3,4) is taken into account, that is, the damage state or relative damage state of each different power transmission path (3,4) is balanced as much as possible.

2. The method (100) according to claim 1, wherein, In the case of two electric drive shafts (1a, 1b), in order to adjust the two electric drive shafts (1a, 1b) or in the case of one electric drive shaft (1), in order to adjust the electric drive shaft (1), the transmission ratio in at least one of the two power transmission paths (3, 4) is adjusted or the power distribution between the two motors (EM1, EM2) is adjusted such that the at least one mechanical component (5) is not subjected to load.

3. The method (100) according to claim 1 or 2 further comprises the following working steps: Check (105a) whether the current value of the damage state or relative damage state of the at least one mechanical component (5) is higher than the first limit value; and If the value exceeds the first limit, then (106a) a threshold is determined for the torque provided by the first motor (EM1) and / or the torque provided by the second motor (EM2), based on the damage component caused by the provided torque, wherein, In the case of two electric drive shafts (1a, 1b), the two electric drive shafts (1a, 1b) are adjusted with regard to the threshold for torque, or in the case of one electric drive shaft (1), the electric drive shaft (1) is adjusted with regard to the threshold for torque.

4. The method (100) according to claim 3, wherein, In the case of two electric drive shafts (1a, 1b), in order to adjust these two electric drive shafts (1a, 1b) or in the case of one electric drive shaft (1), in order to adjust this electric drive shaft (1), the transmission ratio in at least one of the two power transmission paths (3, 4) is adjusted such that the corresponding motor (EM1; EM2) with the threshold can operate at another higher speed at another operating point, or the power distribution between the two motors (EM1, EM2) is adjusted such that the corresponding motor (EM1, EM2) with the threshold can provide or withstand less torque.

5. The method (100) according to claim 1 or 2, wherein, The damage condition was determined as follows: or Where n is the number of revolutions and T is the torque. t is the time step, and p is a parameter representing the intensity of the damage component with respect to the at least one mechanical component (5), wherein the parameter p is set for each corresponding mechanical component (5).

6. The method (100) according to claim 3 further comprises the following working steps: Determine (101b) the temperature value of at least one electrical component (7); Based on the temperature value, determine (102b) the damage component value associated with the at least one electrical component (7) and the damage state value obtained based on the damage component within a predetermined time, wherein, In the case of two electric drive shafts (1a, 1b), both electric drive shafts (1a, 1b) or in the case of one electric drive shaft (1), the electric drive shaft (1) is adjusted while considering the damage state of at least one electrical component (7).

7. The method (100) according to claim 6 further comprises the following working steps: Check (105b) whether the current value of the damage state or relative damage state of the electrical component (7) is higher than the second limit value; If the value exceeds the second limit, then (106b) a threshold for the power supplied by the first motor (EM1) and / or the second motor (EM2) is determined based on the damage component caused by the temperature, wherein, In the case of two electric drive shafts (1a, 1b), both electric drive shafts (1a, 1b) are adjusted, taking into account the threshold for the power supplied.

8. The method (100) according to claim 7 further comprises the following working steps: The at least one electrical component (7) is cooled (108) according to the temperature value.

9. The method (100) according to claim 7 further comprises the following working steps: Provide (103a, 103b) the maximum apportioned damage status (D) for the at least one mechanical component (5) and / or the at least one electrical component (7). max (t)); and Based on the identified damage state (D j (t) and the maximum shared damage state (D) max (t)) Determine the relative damage state (R) of (104a, 104b). j (t)), where, The first limit value and / or the second limit value are defined in relation to the relative damage state.

10. The method (100) according to claim 8, wherein, When adjusting the two motors, the efficiency of both electric drive shafts (1a, 1b) is considered when there are two electric drive shafts (1a, 1b) or when there is one electric drive shaft (1), wherein the paired operating points of the first and second motors (EM1, EM2) are selected such that, while adhering to the threshold for torque and / or the threshold for power, at least one of the two motors (EM1, EM2) achieves operation optimized in terms of efficiency.

11. A system (20) for adjusting two electrically driven shafts (1a, 1b) of a vehicle, each having an electric motor (EM1, EM2), wherein, The first motor (EM1) is connected to the first output terminal (2a) through at least one first power transmission path (3), and the second motor (EM2) is connected to the second output terminal (2b) through at least one second power transmission path (4), or A system (20) for adjusting an electrically driven shaft (1) having two motors (EM1, EM2) that jointly drive an output terminal, wherein the first motor (EM1) is connected to the output terminal via at least one first power transmission path (3) and the second motor (EM2) is connected to the output terminal via at least one second power transmission path (4). The system has: A device (21) for determining the rotational speed and torque value of at least one mechanical component (5) of the power transmission path (3, 4) and / or the motor (EM1, EM2); A device (22) for determining the damage component value associated with the at least one mechanical component (5) based on the applied rotation value and the applied torque value, and determining the damage state value of the at least one mechanical component (5) due to the damage component within a predetermined time. A device (23) for adjusting the two electric drive shafts (1a, 1b) when there are two electric drive shafts (1a, 1b) or when there is one electric drive shaft (1) considering the damage state of the at least one mechanical component (5); and The device for adjusting the two electric drive shafts (1a, 1b) when there are two electric drive shafts (1a, 1b) or when there is one electric drive shaft (1) when there is one electric drive shaft (1) is considered in the context of the damage state or relative damage state of the different power transmission paths (3, 4), and adjusts them in such a way that the damage state or relative damage state of the different power transmission paths (3, 4) is balanced as much as possible.

12. A vehicle having the system (20) according to claim 11.

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