Safety system of a vehicle assembly, method for operating a vehicle assembly and vehicle

Abstract

The present invention relates generally to a safety system (8) of a vehicle assembly (9), a method for operating a vehicle assembly (9), and a vehicle (74). The vehicle assembly (9) comprises an inverter (10) which is coupled to an electric machine (12) by means of n phase lines (40) and configured to provide phase currents for the electric machine (12) by means of the n phase lines (40). A rotor (56) of the electric machine (12) is coupled to an output shaft (58). The safety system (8) has at least one electrically conductive element (41) which, in a tripped state, causes a short circuit of the n phase lines (40). The safety system (8) also includes a first tripping element (44A) configured to cause the movement of the electrically conductive element (41).The safety system (8) further comprises at least one mechanical safety element (61) which, in response to a second control signal, in an actuated state prevents rotation of at least one drive component of the vehicle (74) coupled to the output shaft (58) and / or causes torque decoupling between the rotor (56) of the electric machine (12) and the output shaft (58).

Description

The present invention generally relates to a vehicle assembly backup system, a method of operating a vehicle assembly, and a vehicle.An electrically driven vehicle includes an electric drive machine that operates with multiple phase currents. The phase currents are generated by a converter on the basis of a direct current provided by an electrical energy store. The phase voltage and the phase currents can have relatively high values on account of the relatively high power requirements imposed on the drive machine of the vehicle, which can lead to a safety-relevant situation in the event of an accident of the vehicle or a fault situation in the underlying high-voltage on-board power supply system.In this case, coupling of the converter to the electric machine may be disadvantageous for both components, depending on which fault case occurs. For example, the high phase currents prevailing in the electric machine can unintentionally cross-talk to the converter and damage it.Another problem exists in connection with permanently excited machines, for example synchronous machines. Since the rotor of these machines is typically coupled to a drive component, rotation of the drive component leads to continuous power generation due to the permanent excitation of the rotor, even if the machine should be (electrically) disconnected from the converter. This may cause a thermal event.The object of the invention is therefore to eliminate or at least to reduce the disadvantages of the prior art. In particular, it is desirable to ensure a robust and loadable safety mechanism for a fault case of a vehicle assembly comprising a converter and an electric machine coupled to the converter.The object is achieved by the subject matters of the independent claims. Advantageous embodiments are specified in the dependent patent claims and the following description, each of which can represent aspects of the invention individually or in (sub)combination. Some features are explained in relation to devices, others in relation to methods. However, the aspects are to be transferred respectively in mutually corresponding fashion.According to one aspect, a vehicle assembly security system is provided. The vehicle assembly includes an inverter coupled to an electric machine via n phase lines. The converter is configured to provide phase currents for the electric machine by means of the n phase lines. n is a natural number greater than 1. a rotor of the electric machine is coupled to an output shaft.The securing system has at least one electrically conductive element which is arranged such that it can be moved in such a way that the electrically conductive element can be moved from a basic state into a triggered state. The electrically conductive element does not cause a short circuit of the n phase lines in the basic state and causes a short circuit of the n phase lines in the triggered state.The fuse system also includes a first trip element configured to cause the electrically conductive element to move from the ground state to the tripped state in response to a first control signal.The securing system further comprises at least one mechanical securing element. The at least one mechanical securing element is arranged and configured such that it is movable from a basic state to an actuated state in response to a second control signal. The mechanical securing element is designed such that it prevents rotation of at least one drive component of the vehicle coupled to the output shaft and / or brings about torque decoupling between the rotor of the electric machine and the output shaft.The securing system thus configured advantageously ensures a two-stage securing mechanism. A first stage of the safety mechanism is formed by the electrically conductive element. The electrically conductive element can be used to ensure a short circuit of the phase lines. As a result, the electric machine is effectively decoupled from the converter with regard to a possible current flow. In other words, the electrically conductive element ensures electrical decoupling of the converter from the electric machine. A second stage of the safety mechanism is formed by the mechanical safety element. The mechanical securing element can ensure that current can no longer be generated in the electric machine. This is ensured either by blocking the drive component coupled to the rotor or by cancelling the torque coupling between the rotor and the drive component.It can thus be prevented that even in the case of an electric machine which is already electrically decoupled from the converter, current can be generated in the electric machine continuously by moving a drive component coupled to the rotor. In particular in the case of the electric machine electrically decoupled from the converter, continuous power generation would possibly be problematic, since the current would only circulate within the electric machine through the short-circuited phase lines. Since the electrical energy is not otherwise implementable, it would typically be converted into heat. As a result, the electric machine would heat up strongly and with it also the further components surrounding it. This can potentially lead to a thermal event, i.e. damage caused by excessively high temperatures. For example, the converter itself could thus be damaged since it is generally arranged geometrically close to the electric machine. The likelihood of a thermal event would further increase with continued power generation based on rotation of a drive component coupled to the rotor of the electric machine.The present safety system addresses both problem aspects of a fault case. This ensures a robust and durable safety mechanism, by means of which damage can be effectively prevented and can also be continuously prevented.The electric machine generally includes a stator and a rotor coupled thereto. The stator has windings which are subjected to the phase currents in order to ensure a magnetic field for driving the rotor. The windings are typically arranged in 3m winding sets. m is a natural number of 1 or greater.Optionally, the output shaft may be directly mechanically coupled to the rotor. Alternatively, the output shaft can also be coupled only indirectly to the rotor, for example via a reduction gear.The mechanical securing element can be understood to mean a securing element that ensures a movement of at least one locking component in the actuated state in order to ensure the named protective mechanisms. For this purpose, the mechanical securing element can form, in particular, a frictional connection and / or a positive connection and / or a frictional connection based on the securement component. As a result, the mechanical securing element can, in the actuated state, prevent, based on the locking component, in particular a movement of the rotor, or of a drive component coupled to the output shaft.The drive component of the vehicle coupled to the output shaft is to be designed to be broad in the present case. In particular, the drive component can represent a component that is movable by external influence. For example, the drive component can be a drive wheel of the vehicle which can be driven by a movement of the vehicle. Even if the vehicle itself can no longer ensure driving of the drive wheel in the event of a fault, the vehicle can be moved by external influences, for example during towing. This can cause a rotation of the drive wheel, which would generally result in a rotation of the rotor of the electric machine. However, the mechanical securing element can then prevent the torque transmission between the drive wheel and the rotor or can prevent mobility of the drive wheel per se.According to a further aspect, a method for operating a vehicle assembly is also provided. The vehicle assembly includes an inverter coupled to an electric machine via n phase lines. The converter is configured to provide phase currents for the electric machine by means of the n phase lines. n is a natural number greater than 1. a rotor of the electric machine is coupled to an output shaft. The method comprises at least the steps:A fault case is detected in which a securing of the electric machine is to be carried out.In response to the detection of the fault case, at least one electrically conductive element is moved from a basic state into a triggered state. The electrically conductive element does not cause a short circuit of the n phase lines in the ground state. The electrically conductive element causes a short circuit of the n phase lines in the triggered state.In response to detecting the fault event, a mechanical securing element is moved from a basic state to an actuated state. The mechanical securing elementprevents rotation of at least one drive component of the vehicle coupled to the output shaft in the actuated state, and / orIn the actuated state, a torque decoupling occurs between the rotor of the electric machine and the output shaft.The advantages which are achieved by the safety system explained above are also ensured in a corresponding manner by the method for operating a vehicle assembly which is illustrated here. In particular, a two-stage safety mechanism is provided for the vehicle assembly.Optionally, the vehicle assembly can comprise at least the converter and the electric machine.Preferably, the mechanical securing element is movable from a basic state to the actuated state by a second triggering element based on the second control signal. In the basic state, the mechanical securing element has no influence on a rotation of the at least one drive component coupled to the output shaft or on the torque decoupling between the rotor of the electric machine and the output shaft. By means of the second triggering element, the mechanical securing element can be moved in particular irreversibly between the basic state and the actuated state. The second release element thus prevents the mechanical securing element from dropping back into the basic state. The risk of incorrect actuations of the mechanical securing element is thus reduced.In the present case, irreversible is understood to mean that the mechanical securing element is at least not movable back into the basic state without dedicated maintenance activities. This means that the mechanical securing element is in particular not movable back into the basic state during the usual operation of the vehicle by an intrinsic vehicle function. For example, an exchange of the mechanical securing element may be necessary so that a basic state can be ensured again.The first triggering element may be configured to cause a mechanical pulse in response to the first control signal, by which the electrically conductive element is moved from the ground state to the triggered state. Thus, the short circuit of the n phase lines can be effected in a particularly reliable manner.The second triggering element may be configured to cause a mechanical impulse in response to the second control signal, by which the mechanical securing element is moved from the basic state to the actuated state. Thus, the rotation of at least one drive component of the vehicle coupled to the output shaft can be prevented in a particularly reliable manner, and / or the torque decoupling between the rotor of the electric machine and the output shaft can be brought about in a particularly reliable manner.Optionally, the vehicle assembly further comprises a controller. The control device is configured to trigger the second control signal when a rotational speed of the at least one drive component coupled to the output shaft falls below a rotational speed threshold value. This prevents the mechanical securing element from already being triggered even though the drive component coupled to the output shaft still has an excessively high rotational speed. In this case, the actuation of the mechanical securing element could cause undesired damage, which can thus be effectively prevented.The speed threshold may be predetermined. The speed threshold value can also depend on further parameters of the drive and / or of the vehicle. For example, the control device of the vehicle assembly may be coupled to a higher-order vehicle control device to adjust the speed threshold value based on vehicle parameters.In a preferred embodiment, the speed threshold is zero. This means that the control device is configured to trigger the second control signal when a rotation of the at least one drive component coupled to the output shaft is at least temporarily stopped. Then, the mechanical securing element can prevent the drive component from re-starting.The control device can also be configured to trigger the first control signal, in particular after detection of a fault case.In some embodiments, the control device triggers the protection mechanisms (the first and / or the second control signal) comprising a movement of the electrically conductive element and the mechanical safety element in the event of a fault. The fault event can comprise, in particular, a collision event of an underlying vehicle or a fault of the high-voltage on-board power supply system.The fault case represents in this respect a configuration in which it is assumed that there is an increased risk of unintentional functioning of the high-voltage on-board power supply system or damage thereto. The fault case indicates that a securing of the electric machine is to be triggered. This can potentially cause damage to further components of the system and risks to the environment, users of the vehicle or occupants. The protection mechanisms thus ensure that the risk of further damage or risks to the environment, user or occupant is minimized. For triggering the protection mechanisms, the control device may also receive a superordinate control signal, for example from a vehicle control device which detects a collision event on the basis of measurement data from sensors.In some embodiments, the first triggering element and / or the second triggering element comprises a pyrotechnic element. The respective pyrotechnic element can be ignited by the corresponding first control signal or second control signal. The first pyrotechnic element ignited can cause the movement of the electrically conductive element from the basic state into the triggered state. The second pyrotechnic element that is ignited can bring about the influence of the mechanical securing element on a rotation of the at least one drive component coupled to the output shaft or the torque decoupling between the rotor of the electric machine and the output shaft. The respective pyrotechnic element can ensure, in particular, irreversibility of the actuation of the electrically conductive element or of the mechanical securing element. In addition, the reaction time of pyrotechnic elements is very short, so that the intended protective effect can be ensured with advantageously short latencies.The mechanical securing element preferably comprises a coupling between the rotor of the electric machine and the at least one drive component coupled to the output shaft. The mechanical safety element is configured to open the clutch in response to the second control signal. This ensures freedom from frictional engagement between the drive component and the rotor. In particular, a mechanical decoupling between these components is thus ensured. The coupling represents a possibility of reversibly configuring at least a part of the mechanical safety concept. For example, the actuation of the mechanical securing element can be such that it is irreversibly moved into the actuated state, but that the clutch itself can be moved again, for example by downstream maintenance work, into an engaged state in which a frictional connection between the drive component and the rotor can be ensured.Optionally, the electric machine is configured to drive drive wheels of the vehicle. The mechanical securing element then has a parking lock for the drive wheels of the vehicle, or at least for a single wheel thereof. The parking lock forms at least partially the mechanical securing element. A parking lock is typically present in all vehicles for at least one or all drive wheels of the vehicle or for at least the wheels of a drive axle and is configured to prevent a rotation of the respective drive wheel. As a result, only a slight adaptation of already existing vehicles or vehicle concepts is necessary in order to ensure the safety system outlined here. For example, the parking lock would merely have to be extended by an operative connection to a second triggering element, upon the triggering of which the parking lock is at least not releasable in accordance with the usual use of the vehicle.In an alternative, the vehicle may also have an axle without a parking lock. For example, the vehicle may have a non-driven axle that is fixable by a parking brake. The parking brake can then optionally additionally form part of the mechanical securing element. This means that the mechanical securing element can also fix wheels of axles of the vehicle which are not coupled to the electric drive machine. The vehicle is then no longer readily movable. Typically, a movement (transport) of the vehicle would then not be ensured with at least partially rolling wheels, but with the aid of a lifting device, for example a mobile crane. Therefore, the use of a parking brake from non-driven wheels may additionally reduce the likelihood that the electric machine is still being driven.Preferably, the electrically conductive element is arranged in the basic state such that the electrically conductive element is in electrically conductive contact with none or at most one of the n phase lines. This prevents a short circuit between the phase lines in the ground state.In some embodiments, the electrically conductive element comprises a stud or a bus bar. The bolt or the busbar is arranged over the n phase lines during the movement from the basic state to the triggered state. In particular, the bolt or the busbar is in electrically conductive contact with the n phase lines in the triggered state. The bolt or the busbar can ensure electrical contact between the phase lines in a particularly efficient manner.The electrically conductive element preferably ensures a short circuit between all of the n phase lines. As a result, all phase lines are short-circuited to one another, so that a current flow between the electric machine and the converter can be prevented for all phase lines.Optionally, the electrically conductive element has an electrical resistance which is less than the effective resistance of the converter. This ensures that the phase currents present in the electric machine flow via the electrically conductive element on account of the lower resistance, provided this is arranged in the triggered state.The phase lines between the converter and the electric machine preferably do not need to be mechanically decoupled. This means that the phase lines can in principle remain intact. However, since the electrically conductive element can have a lower electrical resistance than the effective resistance of the converter, at least the main part of the phase currents present in the electrical machine flows via the electrically conductive element, provided this is arranged in the triggered state. The current flow to the converter can thereby be significantly reduced despite still present mechanically intact phase lines. The converter can thus be protected from damage.The electric machine is preferably a permanently excited synchronous machine. In principle, the safety system can also be applied to other types of machines, for example externally excited machines or asynchronous machines. However, these types of machines sometimes do not have the problem that rotation of the rotor necessarily leads to power generation. In contrast, in permanently excited machines, there is a problem that rotation of the rotor continuously leads to power generation. In the case of short-circuited phase lines, the current then generated is typically converted into heat, as a result of which a thermal event may be fundamentally caused. The present safety system is therefore of great advantage, in particular in the case of permanently excited synchronous machines.The securing system can comprise at least one first spring which is designed to move the electrically conductive element from the basic state to the triggered state by spring force. Furthermore, the securing system can comprise a first retaining element which is designed to hold the electrically conductive element in the basic state against the spring force.The securing system can also comprise a second spring which is designed to move the mechanical securing element from the basic state into the actuated state by spring force. Furthermore, the securing system can comprise a second retaining element which is designed to hold the mechanical securing element in the basic state counter to the spring force.A spring and a retaining element can be assigned to a triggering element.The triggering element can be designed to act on the retaining element assigned to it in response to the corresponding control signal (e.g. to break up the retaining element) in such a way that the electrically conductive element or the mechanical securing element is moved from the basic state into the triggered or actuated state by the spring force. Thus, the effect ensured by the electrically conductive element or mechanical securing element can be effected in a particularly reliable manner.The electrically conductive element may be part of a switching contactor in order to provide a particularly reliable short-circuit device.According to a further aspect, the method is executed at least partially in a computer-implemented manner. In particular, a computer program product may be provided which is configured to be executed on a processor (e.g. on a control device of a vehicle) and which comprises instructions which, when executed by the processor, cause the processor to carry out methods as described herein.According to a further aspect, a computer-readable storage medium is also provided. The storage medium may include a computer program product configured to be executed on a processor (e.g., on a controller of a vehicle) and including instructions that, when executed by the processor, cause the processor to perform methods as described herein.According to an additional aspect, a vehicle having a vehicle assembly safety system as described above is also provided, or having a vehicle assembly safety system which can be operated according to the method described above.Optionally, the vehicle may be a motor vehicle.Within the meaning of the present invention, vehicles (motor vehicles) can comprise, in particular, land vehicles having an electric machine, namely, inter alia, tricycles, trikes, quads, off-road and road vehicles such as passenger cars, buses, trucks, tractors and other commercial vehicles, rail vehicles (trains). The vehicles may preferably have at least one electric machine serving for the propulsion of the vehicle. Vehicles may be manned or unmanned. In addition to pure electric vehicles (BEV), plug-in hybrids (PHEV) and fuel cell vehicles (FCEV) may also be included.The invention and further advantageous embodiments and developments thereof are described and explained in more detail below with reference to the examples illustrated in the drawings. The features to be gathered from the description and the drawings can be used according to the invention individually or together in any combination. The following are shown:FIG. 1 shows a schematic illustration of parts of a safety system according to the invention of a vehicle assembly,FIG. 2 shows a further schematic illustration of parts of a securing system according to the invention of a vehicle assembly,FIG. 3 shows a schematic illustration of a method according to the invention for operating a vehicle assembly, andFIG. 4 shows a schematic illustration of a vehicle according to the invention with a securing system according to the invention.FIG. 1 shows a schematic illustration of parts of a securing system 8 according to the invention of a vehicle assembly 9.The vehicle assembly 9 has a converter 10 and an electric machine 12 coupled to the converter 10. In the present case, the electric machine 12 is designed as a permanently excited synchronous machine.The converter 10 (generally: converter) comprises, according to this embodiment, a B6 bridge 14 having three half bridges 16.Each half bridge 16 comprises in the present case a first power switch 18, which is designed here in the form of a transistor and acts as a high-side switch, and a second power switch 20, which is likewise designed in the form of a transistor and acts as a low-side switch. Between the first power switch 18 and the second power switch 20, each half bridge 16 comprises a center tap 22 for providing a phase current signal, here V, to the electric machine 12.The three half bridges 16 apply three corresponding phase current signals to the electric machine 12, U, V and W. However, other topologies, for example a six-phase electric machine 12, are likewise possible, which then require corresponding modifications of the converter 10.The respective half bridges 16 are coupled to a busbar structure 24 of the converter 10. The inverter 10 is coupled to a DC power source 26. The DC power supply 26 comprises terminals 28, 30, between which a high voltage HV is provided, for example 800 V.In addition, the converter 10 comprises an intermediate circuit capacitor 34, which serves as a coupling element between the DC power source 26 and the electric machine 12.Depending on the switching positions of the power switches 18, 20, corresponding commutation cells are formed in the converter 10 when the high voltage is applied.In order to control the switching positions of the power switches 18, 20, the converter 10 is coupled to a control device 36 of the vehicle assembly 9, which control device comprises at least one data processing device 38. The controller 36 is coupled to the circuit breakers 18, 20.The control device 36 is configured to provide corresponding gate signals G 1, G 2 as digital switching signals for the circuit breakers 18, 20 at least indirectly. For example, the digital control signals G 1, G 2 may be processed by respective gate driver circuits, which as a result provide respective control voltages for influencing the gate electrodes of the power switches 18, 20. This means that, based on the digital switching signals of the control device 36, the switching positions of the power switches 18, 20 are influenced.The converter 10 comprises phase lines 40, which are coupled on the one hand to the center taps 22 of the half bridges 16, and on the other hand to the electric machine 12. Generally, the inverter 10 is coupled to the electric machine 12 via n phase lines 40, where n is a natural number greater than 1.According to this embodiment, the securing system 8 comprises at least one electrically conductive element 41, which is designed here as a bolt 42 made of an electrically conductive material. The electrically conductive material has in particular a low specific electrical resistance, in this respect therefore a high electrical conductivity.The fuse system 8 further comprises a first trip element 44A coupled to the electrically conductive element 41.During usual use of the vehicle assembly 9, the electrically conductive member 41 is arranged in the ground state. In the basic state, the electrically conductive element 41 is arranged in the present case such that it is not in electrically conductive contact with any of the phase lines 40.According to this embodiment, the first triggering element 44A includes a first pyrotechnic element 46A, a first spring 50A, and a first retaining element 52A.The first spring 50A is configured to exert a spring force on the electrically conductive element 41 by means of which the electrically conductive element 41 is movable from the basic state into a released state (dashed line) along the arrow 48.The first retaining member 52A is configured to apply a retaining force to the electrically conductive member 41 to keep the electrically conductive member 41 in the ground state against the spring force of the first spring 50A at least as long as the first retaining member 52A is intact.The first pyrotechnic element 46A is coupled to the retaining element 52A such that triggering of the first pyrotechnic element 46A results in the retaining force exerted by the first retaining element 52A on the electrically conductive element 41 being canceled. This means that the electrically conductive element 41 is moved into the triggered state along the arrow 48 after triggering of the first pyrotechnic element 46A by the spring force exerted by the first spring 50A.In the triggered state, the electrically conductive element 41 is in electrically conductive contact with all phase lines 40. The specific electrical resistance of the electrically conductive element 41 is lower than the effective resistance of the converter 10. As a result, the phase currents prevailing in the electric machine 12 are converted into heat.Alternatively or additionally, the safety system 8 can comprise a mechanical (switching) contactor in order to bring about the short circuit of the phase lines 40.The control device 36 is configured to transmit a first control signal to the first triggering element 44A. As a result of the first control signal, the first pyrotechnic element 46A may be fired.The control device 36 is configured to trigger the first control signal, in particular in the event of a collision of the underlying vehicle or in the event of a fault of the underlying high-voltage on-board power supply system. In order to determine a corresponding fault case, the control device 36 may be coupled to a higher-order vehicle control device.FIG. 2 shows a further schematic illustration of parts of a securing system 8 according to the invention of a vehicle assembly 9.The electric machine 12 includes a stator 54 and a rotor 56 coupled thereto.The rotor 56 is coupled to an output shaft 58 for transmitting torque to a drive wheel 60 of the vehicle.According to this embodiment, the securing system 8 additionally comprises a mechanical securing element 61, which is designed in the present case as a coupling 62.A second triggering element 44B is functionally designed in a manner corresponding to the first triggering element 44A and is coupled to the mechanical securing element 61.The mechanical securing element 61 is arranged in the basic state in a usual operating state of the vehicle assembly 9 and ensures a torque coupling between the rotor 56 of the electric machine 12 and the drive wheel 60 of the vehicle.The control device 36 is configured to output a second control signal to the second trigger element 44B. As a result of the second control signal, the mechanical securing element 61 is moved from the basic state to the actuated state. For this purpose, the second triggering element 44B is used, the second pyrotechnic element 46B of which, after ignition, can cancel the retaining force exerted by the second retaining element 52B on the mechanical securing element 61. As a result, the mechanical securing member 61 is moved from the basic state to the operated state by the spring force provided by the second spring 50B.In the actuated state, the clutch 62 prevents torque coupling between the rotor 56 of the electric machine 12 and the drive wheel 60 of the vehicle (see dashed lines) because the clutch 62 is then open. This means that the open clutch ensures torque decoupling between the rotor 56 and at least a part of the output shaft 58.Rotation of the drive wheel 60 then no longer causes rotation of the rotor 56 of the electric machine 12. Thus, a power generation in the electric machine 12 is prevented, in particular for permanently excited machine types.In an alternative, the mechanical securing element 61 may be directly coupled to the drive wheel 60 of the vehicle. The mechanical securing element 61 can then be designed as a parking lock 64. The parking lock 64 may be configured to inhibit rotation of the vehicle drive wheel 60 as it is moved to the actuated state by the second trigger 44B. In this case, the drive wheel 60 is still coupled to the rotor 56 of the electric machine 12 via the output shaft 58. However, since rotation of the drive wheel 60 is prohibited by the parking lock 64, power generation in the electric machine 12 is prohibited.FIG. 3 shows a schematic illustration of a method 66 according to the invention for operating a vehicle assembly 9.In step 68, a fault case is detected in which a securing of the electric machine 12 is to be carried out. For example, the detection can be based on a higher-level vehicle control unit detecting a collision event or a fault in the high-voltage on-board power supply system and transmitting a corresponding control signal to the control device 36 of the vehicle assembly 9.In step 70, in response to step 68, at least one electrically conductive element 41 is moved from a ground state to a triggered state. The electrically conductive element 41 does not cause a short circuit of the n phase lines 40 in the basic state.In step 72, in response to step 68, at least one mechanical securing element 61 is moved from a ground state to an actuated state. The mechanical securing element 61 prevents, in the actuated state, a rotation of at least one drive component of the vehicle coupled to the output shaft 58.Alternatively or cumulatively, the mechanical securing element 61 brings about torque decoupling between the rotor 56 of the electric machine 12 and at least part of the output shaft 58 in step 72.Step 72 is preferably only triggered when a rotational speed of the at least one drive component, for example of a drive wheel 60 of the vehicle, coupled to the output shaft 58 falls below a rotational speed threshold value. The rotational speed threshold value can be predetermined in this case. A corresponding sensor can be provided in order to detect the rotational speed of the drive component. Damage can thereby be avoided by the mechanical securing element 61 being only released when the rotational speed is correspondingly low.FIG. 4 shows a schematic illustration of a vehicle 74 according to the invention with a securing system 8 according to the invention of a vehicle assembly 9.The vehicle 74 has drive wheels 60, which are driven in the present case by an electric machine 12. The electric machine 12 is coupled to an inverter 10. The vehicle assembly 9 further comprises a control device 36 which is coupled to an electrically conductive element 41 and a mechanical securing element 61 designed as a coupling 62. Alternatively, the mechanical securing element 61 can also be designed as a parking lock 64.The safety system 8 can be operated at least according to the method 66.In the present application, amounts and numbers may be referred to. Unless expressly stated, such amounts and numbers are not to be considered as limiting, but as examples of the possible amounts or numbers in connection with the present application. In this context, the term "plurality" may also be used in the present application to refer to a quantity or number. In this context, the term "plurality" means any number greater than one, e.g., two, three, four, five, etc. The terms "about", "about", "near", etc. mean plus or minus 5% of the stated value.

Claims

A fuse system (8) of a vehicle assembly (9), wherein the vehicle assembly (9) comprises an inverter (10) which is coupled to an electric machine (12) by means of n phase lines (40) and is configured to provide phase currents for the electric machine (12) by means of the n phase lines (40), wherein n is a natural number greater than 1, wherein a rotor (56) of the electric machine (12) is coupled to an output shaft (58), wherein the fuse system (8) has at least one electrically conductive element (41) which is arranged such that it is movable in such a way that the electrically conductive element (41) is movable from a basic state into a triggered state and which does not cause a short circuit of the n phase lines (40) in the basic state and a short circuit of the n phase lines (40) in the triggered state, and a first triggering element (44A) which is configured to:, in response to a first control signal, to cause the movement of the electrically conductive element (41) from the basic state to the triggered state, wherein the securing system (8) further comprises at least one mechanical securing element (61), wherein the at least one mechanical securing element (61) is arranged and configured such that it is movable from a basic state to an actuated state in response to a second control signal and is configured such that it prevents a rotation of at least one drive component of the vehicle (74) coupled to the output shaft (58) and / or brings about a torque decoupling between the rotor (56) of the electric machine (12) and at least a part of the output shaft (58).The safety system (8) according to claim 1, characterized in that the mechanical safety element (61) is movable from a basic state to the actuated state by a second triggering element (44B) based on the second control signal, and wherein the mechanical safety element (61) has no influence in the basic state on a rotation of the at least one drive component coupled to the output shaft (58) or on the torque decoupling between the rotor (56) of the electric machine (12) and the output shaft (58).Safety system (8) according to Claim 2, characterized in that the vehicle assembly (9) furthermore has a control device (36) which is configured to trigger the second control signal if a rotational speed of the at least one drive component coupled to the output shaft (58) falls below a rotational speed threshold value.The safety system (8) according to any one of the preceding claims, characterized in that the first triggering element (44A) and / or the second triggering element (44B) comprises a pyrotechnic element (46A, 46B), which can each be ignited by the corresponding first control signal or second control signal, and wherein the movement of the electrically conductive element (41) from the basic state into the triggered state can be effected by the ignited first pyrotechnic element (46A), and wherein the influence of the mechanical safety element (61) on a rotation of the at least one drive component coupled to the output shaft (58) or the torque decoupling between the rotor (56) of the electric machine (12) and the output shaft (58) can be effected by the ignited second pyrotechnic element (46B).The safety system (8) according to any one of the preceding claims, characterized in that the mechanical safety element (61) comprises a coupling (62) between the rotor (56) of the electric machine (12) and the at least one drive component coupled to the output shaft (58), and wherein the mechanical safety element (61) is configured to open the coupling (62) in response to the second control signal.The safety system (8) according to any one of the preceding claims 1 to 4, characterized in that the electric machine (12) is configured to drive drive wheels (60) of the vehicle (74), and wherein the mechanical safety element (61) comprises a parking lock (64) for the drive wheels (60) of the vehicle (74), wherein the parking lock (64) at least partially forms the safety element (61).The fuse system (8) according to any one of the preceding claims, characterized in that the electrically conductive element (41) comprises a bolt (42) or a busbar which is arranged over the n phase lines (40) during the movement from the initial state to the triggered state.The safety system (8) according to any one of the preceding claims, characterized in that the electric machine (12) is a permanently excited synchronous machine.Method for operating a vehicle assembly (9), wherein the vehicle assembly (9) comprises an inverter (10), which is coupled to an electric machine (12) by means of n phase lines (40), and is configured to provide phase currents for the electric machine (12) by means of the n phase lines (40), wherein n is a natural number greater than 1, wherein a rotor (56) of the electric machine (12) is coupled to an output shaft (58), and the method has at least the steps of: - detecting a fault case in which a securing of the electric machine (12) is to be carried out; - in response to the detection, moving at least one electrically conductive element (41) from a basic state to a triggered state, wherein the electrically conductive element (41) does not cause a short circuit of the n phase lines (40) in the basic state and a short circuit of the n phase lines (40) in the triggered state, and - in response to the detection, moving a mechanical securing element (61) from a basic state to an actuated state, wherein the mechanical securing element (61), in the actuated state ◯ prevents a rotation of at least one drive component of the vehicle (74) coupled to the output shaft (58) and / or ◯ brings about a torque decoupling between the rotor (56) of the electric machine (12) and the output shaft (58).A vehicle (74) comprising a vehicle assembly (9) according to any one of claims 1 to 8 or a vehicle assembly (9) operable according to the method of claim 9.

Images