Powertrain for a motor vehicle

Abstract

The invention relates to a powertrain for a motor vehicle, having at least one first drive motor (10), a second drive motor (14) designed as an electric motor, a planetary gearing unit (20), an output shaft (22), and a shift element (24). The planetary gearing unit (20) has a planetary gear set (30) comprising a sun gear (32), a planet carrier (34), and a ring gear (36). A first motor shaft (12) can be mechanically operatively connected to the sun gear (32), a second motor shaft (16) is mechanically operatively connected to the ring gear (36), and the planet carrier (34) is permanently connected to the output shaft (22) for conjoint rotation therewith. The planetary gear set (30) can be blocked by means of the shift element (24). The first sun gear (32), the first motor shaft (12), and the second motor shaft (16) are coaxial to one another. The invention also relates to a motor vehicle.

Description

[0001] Drivetrain for a motor vehicle

[0002] The present invention relates to a drive train for a motor vehicle. The invention also relates to a motor vehicle.

[0003] State of the art

[0004] Affordable mobility is an important factor for a country's economic development. In many economically weak countries, small vehicles with combustion engines, such as scooters, are used for this purpose. However, such vehicles often cause significant environmental pollution, for example through their noise levels and CO2 and pollutant emissions.

[0005] A drive system for such vehicles that is quiet and produces low emissions would therefore be desirable. Pure electric drives, for example, are suitable for this. However, a pure electric drive requires a suitable infrastructure that ensures a sufficient power supply. Furthermore, a sufficiently large energy storage system is very expensive, heavy, and environmentally unfriendly to produce.

[0006] Hybrid drives are another option for reducing CO2 and pollutant emissions. With hybrid drives, an electric motor can power the vehicle emission-free, for example, at low urban speeds. At higher speeds and over long distances, a hybrid drive's internal combustion engine can provide sufficient power and a long range. If necessary, fuel can be supplied to the vehicle much faster than charging a battery would be possible. However, hybrid drives are complex, labor-intensive, and therefore comparatively expensive.

[0007] WO 2021 / 255188 A1 describes a parallel hybrid drive for motor vehicles that is both cost-effective and simple. This hybrid drive is therefore well suited for use in small vehicles, for example. However, due to the many components of a hybrid drive compared to a conventional drive with only an internal combustion engine, integration into small vehicles such as scooters can be difficult. The mounting of the components and the numerous shafts of hybrid drives can also be very complex.

[0008] Description of the invention

[0009] A first aspect relates to a drive train of a motor vehicle. The drive train can, for example, be designed to provide drive power for driving the motor vehicle. The motor vehicle can, for example, be designed as a land vehicle or a watercraft. Examples of a land vehicle are a motor scooter, an ATV, which is also referred to as a quad, or a UTV, an off-road vehicle with a loading area and multiple seats. The motor vehicle can, for example, also be designed as a snowmobile or buggy. Another example is an auto rickshaw, which, for example, has two or three wheels. A watercraft can, for example, be designed as a motorboat.

[0010] The drivetrain comprises a first drive motor with a first motor shaft, a second drive motor with a second motor shaft, a planetary gear, an output shaft, and a shift element. The drivetrain can form a hybrid drive for the motor vehicle.

[0011] The first drive motor can, for example, be designed as an internal combustion engine. The internal combustion engine can, for example, be designed as a gasoline engine or diesel engine. The internal combustion engine can, for example, be designed as a two-stroke engine or four-stroke engine. The internal combustion engine can be designed to convert chemical energy into mechanical energy. Drive power can, for example, be provided at the first motor shaft by the first drive motor. The first motor shaft can, for example, be designed as a crankshaft. The first drive motor can be free of a further motor shaft, and the designation as the first motor shaft can merely serve to associate it with the first drive motor. The second drive motor is designed as an electric motor. In the following, the second drive motor is therefore also referred to as the electric motor. An electric motor can have a rotor and a stator.The stator can be designed as a radially closed stator or formed by stator segments. The second motor shaft can be designed as the rotor of the electric motor or be permanently connected to the rotor for rotation. The electric motor can be designed to convert electrical energy into mechanical energy. The electric motor can optionally also be designed for recuperation. Examples of an electric motor are an asynchronous motor and a synchronous motor. Drive power can be provided at the second motor shaft by the second drive motor, for example. The second drive motor can be free of a further motor shaft. The designation as a second motor shaft can merely serve as an assignment to the second drive motor.

[0012] The output shaft can form an output shaft of the planetary gear set or be mechanically operatively connected to it. The output shaft can, for example, have a toothing. The output shaft is formed, for example, by a pinion. The output shaft can be permanently rotationally fixed or mechanically operatively connected to an output element of the motor vehicle, such as a rear wheel, a ship's propeller, or a driven rear axle. For example, the output shaft can be permanently rotationally fixed directly to the rear wheel or mechanically operatively connected to the rear wheel via a chain or spur gear stage. Another transmission, such as a reduction gear, can also provide the mechanical operative connection between the output shaft and the output element of the motor vehicle. The output shaft can, for example, be mechanically operatively connected to two rear wheels via an axle differential.The connection to one or more output elements of the motor vehicle can also include a bevel gear stage. The output shaft can therefore be permanently connected to one or more output elements in a rotationally fixed manner or be mechanically connected.

[0013] The planetary gear set can be configured to transmit drive power from the first drive motor and the second drive motor to the output shaft. The planetary gear set can provide a gear ratio. The planetary gear set can, for example, comprise a planetary gear set. The first motor shaft and the second motor shaft can each be mechanically connected to the output shaft via the planetary gear set. The planetary gear set can have two input shafts and one output shaft. The planetary gear set can be configured to sum the drive power of the two drive motors in at least certain driving conditions.

[0014] The planetary gear train has a planetary gear set. The planetary gear set has a sun gear, a planet carrier, and a ring gear. The planetary gear set is designed, for example, as a minus planetary gear set or a plus planetary gear set. The sun gears, planet carrier, and ring gears of a planetary gear set form, for example, its rotating elements. Each planetary gear set can have one or more planet gears that are rotatably attached to the planet carrier. For example, the planet gears of a planetary gear set each mesh with a sun gear and a ring gear of a planetary gear set. Each planetary gear set can be free of any elements other than those mentioned here. Each planetary gear set can be free of any rotating elements other than those mentioned here. An axis of rotation of the planetary gear train can correspond to an axis of rotation of the rotating elements. The axis of rotation of the planetary gear train can define its axial and radial directions.An axial and radial direction of the drive train can correspond to the axial and radial directions of the planetary gear. A rotating element can be formed solely by a gear element, such as a gear, or it can also have a shaft element permanently connected to it in a rotationally fixed manner.

[0015] The first motor shaft is mechanically operatively connected to the sun gear. For example, the first motor shaft can be connected to the sun gear in a rotationally fixed manner or is permanently connected in a rotationally fixed manner. The sun gear can, for example, form a first input shaft of the planetary gear system. This allows the first motor shaft and the sun gear to be easily arranged coaxially. Furthermore, the sun gear can be easily mounted on the first motor shaft. The first motor shaft and the sun gear can, for example, be formed as a single piece. The sun gear can, for example, be permanently connected to the first motor shaft in a rotationally fixed manner using a press connection. For example, the press connection can be designed as a cylindrical press fit, which can require little installation space. For example, the press connection can be designed as a conical press fit, which allows high manufacturing tolerances.The first motor shaft and the sun gear can also be permanently connected to each other in a form-fitting, rotationally secure manner, for example, via a gearing. Such a connection can withstand particularly high loads and allows for easy disassembly for maintenance.

[0016] The second motor shaft can be mechanically connected to the ring gear. The ring gear can, for example, form a second input shaft of the planetary gear system. For example, the second motor shaft can be mechanically connected to the ring gear via a spur gear stage. For example, the second motor shaft can be permanently rotationally connected to the ring gear. This allows the electric motor to be simply arranged radially on the outside of the planetary gear system and enclose it. The ring gear can thus also support the second motor shaft. Conversely, the second motor shaft can also support the ring gear. The electric motor can also be simply arranged coaxially to the planetary gear system. This allows the electric motor to have a large diameter. An electric motor with a large diameter can, for example, provide a particularly high torque. This design can also be advantageous with regard to installation space requirements and the storage and housing of components.

[0017] The planet carrier is permanently connected to the output shaft in a rotationally fixed manner. For example, the planet carrier and the output shaft can be formed as a single piece. The output shaft can, for example, have a pulley or be formed by a pulley that is pressed onto the output shaft. For example, the output shaft can be connected to the planet carrier in a form-fitting or non-forming manner, for example by toothing or a press fit. For example, the output shaft can be designed as a pinion, a pulley, or a gear that is attached to the planet carrier. The planet carrier can form an output shaft of the planetary gear.

[0018] The previously described selection of the input and output shafts for the planetary gear set can result in favorable gear ratios. For example, the electric motor will typically operate most efficiently at higher speeds, while the first drive motor, designed as an internal combustion engine, will operate at relatively lower speeds.

[0019] The planetary gear set can be locked together using the shifting element. The shifting element can be designed, for example, as a multi-plate clutch, dog clutch, or centrifugal clutch. When locked, all rotating elements of the planetary gear set rotate together uniformly. In the locked state, for example, two rotating elements of the planetary gear set are connected to one another in a rotationally fixed manner by the shifting element. For example, the sun gear and the ring gear, the planet carrier and the ring gear, or the sun gear and the planet carrier can be connected to one another in a rotationally fixed manner by means of the shifting element to lock the planetary gear set. The shifting element can be adjustable between an open position and a closed position. In the closed position, the shifting element creates a rotationally fixed connection between two elements. In the open position, two elements are separated from one another by the rotating element.The shifting element is attached to the planetary carrier, for example. The shifting element then only engages with the other rotating element when the planetary gear set is closed. In a locked planetary gear set, the sun gear, planetary carrier, and ring gear rotate at the same speed. Accordingly, the planetary gears no longer roll with their teeth on the sun gear and ring gear, which means that the planetary gear or planetary gear set is very efficient when locked.

[0020] The first sun gear, the first motor shaft, and the second motor shaft can be arranged coaxially to one another. This allows the drive train to be very compact and simple. For example, many elements can be centrally mounted. For example, the sun gear can be mounted on the first motor shaft and the other rotating elements on the sun gear. Instead of on the first motor shaft, the sun gear can also be mounted on a housing of the planetary gear system, for example using two bearings. The sun gear can have a sun shaft element that forms a central bearing shaft. The sun shaft element can be free of teeth and permanently rotationally fixed to a gear element of the sun gear. The sun shaft element and the sun gear element can also be integrally formed. Furthermore, the planetary gear system and / or the electric motor and / or the switching element can be accommodated together in one housing.The planetary gear with the switching element and the electric motor can, for example, be provided as an assembly which can be pre-assembled and integrated into an existing drive.

[0021] The drive train can have a housing. The housing can form an interior space. The housing can, for example, be oil-tight. The housing can have a second through-opening for connecting the first motor shaft and a second through-opening for connecting the output shaft. The housing can have feedthroughs for a power supply to the electric motor. The housing can be split in two parts. This can make assembly particularly simple. For example, the housing can be split axially or radially. The housing can, for example, be made from a cast metal or plastic material. The planetary gear set and / or the electric motor and / or the switching element can be completely accommodated in the housing. The planetary gear set can be designed as an encapsulated planetary gear set. The planetary gear set can, for example, be grease-lubricated or oil-lubricated.Sealed bearings can seal the housing at the through-openings for the respective shafts. The housing can also be designed without sealing, which can make the drive train particularly cost-effective. The housing can be attached to the first drive motor. The stator of the electric motor is, for example, permanently and non-rotatably connected to the housing and / or to the first drive motor. Respective winding heads of the stator can be cooled with liquid through channels in the housing. Alternatively, the winding heads of the stator can also be passively cooled. Using a non-conductive lubricant in the planetary gear system can provide internal cooling of the electric motor, in particular of the rotor, for example if the rotor is arranged together with the planetary gear set in the housing.

[0022] The drive train can have a first energy storage device for the first drive motor, for example designed as a fuel storage device. For example, the drive train can have a gasoline tank. The drive train can have a second energy storage device for the electric motor, for example designed as a battery, capacitor, flywheel or fuel cell. The second energy storage device can be arranged in the housing or, for example, outside the housing. The second energy storage device can have an additional associated housing. The drive train or the electric motor can have an inverter which controls a power supply to the electric motor. The inverter can be arranged in the housing or, for example, outside the housing. The inverter can have an additional associated housing.

[0023] The drivetrain may include a service brake. The service brake may, for example, be configured to decelerate the output shaft, the planetary carrier, or respective output elements of the motor vehicle. The service brake may, for example, include a disc brake or drum brake. The service brake may allow an operating mode in which the first drive motor drives the electric motor to charge the second energy storage device. Furthermore, operating the electric motor with the drive axle braked enables the first drive motor, configured as an internal combustion engine, to start from a standstill.

[0024] The service brake can form a driving brake of the motor vehicle. This allows the number of braking elements to be kept low, for example, limited to one or two brakes. A second brake can also be designed as a service brake. The second brake can be designed to brake a non-driven axle of the motor vehicle, which is designed, for example, as a front axle. While driving, respective service brakes can brake a driving speed of the motor vehicle. For this purpose, respective service brakes can be actuated by the driver of the motor vehicle. The motor vehicle can also be braked by the electric motor recuperating. The deceleration of the motor vehicle through recuperation can occur simultaneously with or alternatively to the deceleration by respective service brakes.

[0025] The drive train can be free of any elements other than those described here, in particular free of any additional shafts, gears, planetary gear sets, rotating elements, and shifting elements. This results in a simple, compact, and cost-effective drive train. If two elements are mechanically operatively connected, they can be directly or indirectly coupled to one another in such a way that a movement of one element can cause a reaction in the other element. For example, a mechanical operative connection can be provided by a positive or frictional connection. With a mechanical operative connection, for example, one or more spur gear stages can be involved in a drive power transmission. For example, the mechanical operative connection can correspond to a meshing of corresponding gearings of two elements.Additional elements, such as one or more spur gear stages, can be provided between mechanically interconnected elements.

[0026] A non-rotatable connection between two elements is defined as a connection in which the two elements are essentially rigidly coupled to each other under all intended conditions. This also includes a frictional connection, which may result in intentional or unintentional slippage. Permanently non-rotatable elements can, for example, be formed as individual components permanently connected to each other in a non-rotatable manner, or even as a single piece.

[0027] A connection between two elements via a further element can mean that this further element can be involved in an indirect operative connection between the two elements. For example, this element can be arranged in the power flow between these two elements. A connection between two elements via two or more elements can mean that these further elements are all involved in an indirect operative connection between the two elements. A switchable connection can enable torque transmission between two elements in one state, for example through a rigid coupling, and essentially interrupt this torque transmission in another state. For this purpose, a corresponding switching element can be provided between the two elements. If two elements can be connected in a rotationally fixed manner, these two elements can be connected to one another in a rotationally fixed manner, for example via a switching element.If two elements can be mechanically connected, they can be connected, for example, via a switching element for torque transmission. In one embodiment of the drive train, the electric motor can be designed as an internal rotor. With an internal rotor, the stator is arranged radially outwards to the rotor. The electric motor can also be arranged radially outwards to the planetary gear set. The electric motor can, for example, enclose the planetary gear set radially on the outside. This allows the drive train to be particularly compact axially. This allows the drive train to be easily integrated into narrow or single-track motor vehicles. The electric motor can also be arranged radially outwards to the switching element and / or the output element.

[0028] In one embodiment of the drive train, it can be provided that the planetary gear and the electric motor are arranged in the same axial region. For example, an axial extent of the electric motor and the planetary gear can therefore at least partially overlap. For example, a toothing of the respective rotary elements of the planetary gear can be arranged axially completely in an extension of the electric motor. This can result in a simple and compact housing. For example, the planetary gear can be arranged axially completely or partially in an axial extension defined by the electric motor. For example, an axial end of the electric motor and an axial end of the planetary gear on a side facing the first drive motor can be essentially the same.

[0029] In one embodiment of the drive train, it can be provided that the shifting element is designed as a automatically switching shifting element. For example, the shifting element can be designed as a centrifugal clutch. A centrifugal clutch is a simple passive shifting element. No actuator is required to adjust a centrifugal clutch, which means that the drive train and its control can be particularly simple. A automatically switching shifting element can, for example, change from its open position to its closed position depending on the speed of a shaft connected to it. For example, the shifting element automatically blocks the planetary gear set when the speed of the sun gear or the planet carrier exceeds a threshold value. For example, at a certain driving speed, the shifting element automatically switches to the blocked state of the planetary gear.This allows the planetary gear set to be automatically shifted to a locked state above a certain driving speed, allowing the drivetrain to operate particularly efficiently at high speeds. Furthermore, particularly high performance can be achieved by combining the drive forces in the planetary gear set, which can enable particularly high driving speeds. Thanks to the efficient power transmission in the planetary gear set, the drivetrain can potentially deliver more power to the output shaft than conventional drives with similar motors.

[0030] If the speed limit at which the planetary gear set locks is exceeded, the first drive motor can be started automatically. For example, the internal combustion engine can be automatically engaged when the speed limit for residential streets is exceeded, providing more power and even higher driving speeds. If the shifting element is designed to switch automatically, the internal combustion engine can be started automatically, for example, when the shifting speed is exceeded, due to the inertia of the hybrid drive.

[0031] Alternatively, the switching element can also be designed as an actively switchable switching element. This allows the switching element to be adjusted at any time, regardless of the driving situation. This allows for more flexible switching between driving modes.

[0032] If the planetary gear set is not locked, the operating speed of the internal combustion engine at a given speed can depend on the speed of the electric motor. This allows the electric motor to control the speed of the internal combustion engine.

[0033] In one embodiment of the drive train, it can be provided that the shifting element is arranged radially between two rotating elements of the planetary gear set, which can be connected to one another in a rotationally fixed manner by means of the shifting element. This allows the drive train to be particularly compact and / or the shifting element can be easily integrated into the housing of the planetary gear set. The shifting element can, for example, be arranged at least partially axially within an axial extension of the planetary gear set. For example, an axial extension of the shifting element can at least partially overlap with an axial extension of the rotating elements, which can be connected by means of the shifting element. For example, the shifting element can be arranged axially next to toothings of the rotating elements of the planetary gear set and the planet gears. For example, the shifting element can be arranged next to the planetary gear set.

[0034] In one embodiment of the drive train, it can be provided that the shifting element is arranged axially next to the planetary gear set and / or the output shaft. For example, the output shaft can be formed by a pinion and the shifting element can be arranged axially between the planetary gear set and the pinion. For example, the shifting element can be arranged axially between the toothing of the rotating elements of the planetary gear set or the toothing of the planetary gears and a connection of the output shaft to the output element, in particular a toothing of the output element. The shifting element can, for example, be arranged axially next to the planetary gear set on a side of the planetary gear set facing away from the first drive motor. As a result, the first motor shaft can be particularly short. Alternatively, the shifting element can, for example, be arranged axially next to the planetary gear set on a side of the planetary gear set facing the first drive motor.This allows the switching element to be mounted particularly stably. The switching element can be designed for dry-running or wet-running operation, for example. A dry-running switching element can easily be located outside the planetary gear housing. A wet-running switching element can easily be integrated into the planetary gear housing.

[0035] In one embodiment of the drive train, it can be provided that the planet carrier is mounted on the sun gear, in particular the sun shaft element. For example, the planet carrier can be rotatably mounted on the sun shaft element. This allows the planet carrier to be mounted with few bearings and / or with a simple design. In addition, the axial extent of the planetary gear can be very small. The planet carrier is mounted on the sun gear, for example, with one or two bearings. The planet carrier is only mounted on the sun gear, for example. In one embodiment of the drive train, it can be provided that the ring gear is mounted on the sun gear. This allows the ring gear to be mounted with few bearings and / or with a simple design. In addition, the axial extent of the planetary gear can be very small. For example, the rotor of the electric motor can be mounted on the sun gear together with the ring gear.Then the rotor does not need to be mounted on the stator of the electric motor or the housing, which is a complex process. The ring gear is mounted on the sun gear, for example, with one or two bearings. The ring gear is mounted only on the sun gear, for example. The ring gear can, for example, be mounted only on the sun gear and the planet carrier, in particular with a first bearing on a first axial side of a toothing of the sun gear on the sun gear and with a second bearing on a second axial side on the planet carrier, opposite the first axial side with respect to the toothing of the sun gear.

[0036] The sun gear can form a main bearing shaft for the planetary gear set and also the electric motor. The shifting element can also be mounted directly or at least indirectly on the sun gear. The drive train, for example, has a total of only six bearings and an optional freewheel for supporting all components of the planetary gear set. Additional bearings can be provided, for example, for the combustion engine. The freewheel is described further below. The sun gear can be mounted at a first axial end on the first motor shaft. For example, the sun gear is not mounted on the housing of the planetary gear set, or is only mounted on one side. The sun gear can be free of bearings at a second axial end facing away from the first axial end. In this case, very few bearings are required. For example, the sun gear is mounted exclusively on the first motor shaft.Alternatively, the sun gear is mounted on the planetary gear housing via a bearing, for example, at the second axial end. An additional bearing can be provided for this purpose, or the bearing can be formed by the optional freewheel.

[0037] In one embodiment of the drive train, the drive train can be provided with a freewheel by means of which the first motor shaft can be locked. This can be the previously mentioned freewheel. The freewheel can be designed to prevent rotation of the first drive motor in one direction of rotation. As a result, the output shaft can be driven independently of the first drive motor by means of the electric motor. This enables a purely electric drive of the motor vehicle.

[0038] The freewheel can be designed, for example, to block rotation of the internal combustion engine in a reverse direction. The freewheel can be designed to connect the first motor shaft to the housing of the first drive motor or the planetary gear in a rotationally fixed manner. The freewheel can be designed, for example, to operate with frictional engagement or positive engagement.

[0039] A freewheel can be self-actuating, eliminating the need for actuators to operate the freewheel. The freewheel can then be actuated automatically by the operation of the drivetrain, for example, based on the respective states of the two drive motors. This allows the drivetrain to be compact and cost-effective. Furthermore, no manual operation is necessary. This simplifies the operation of the vehicle.

[0040] The freewheel can be designed to automatically lock the first motor shaft depending on a first direction of rotation of the first motor shaft. The freewheel can be designed to automatically release rotation of the first motor shaft depending on a second direction of rotation of the first motor shaft that is opposite to this. For example, the freewheel can be designed as a roller freewheel. An example of a roller freewheel is a ball bearing, which is designed to allow rotation of a shaft mounted thereon in the first direction of rotation and to block it in the second direction of rotation that is opposite to this. The freewheel can also be designed, for example, as a pawl freewheel or a sprag freewheel.

[0041] Alternatively, a further switching element can be provided instead of the freewheel. The further switching element can be designed to lock the first motor shaft when actuated. The actively switchable further switching element can enable recuperation by the electric motor in multiple states of the hybrid drive. The freewheel or the further switching element can be connected directly to the first motor shaft. The first freewheel or the further switching element can also be connected indirectly to the first motor shaft, for example, via the sun gear.

[0042] In one embodiment of the drive train, it can be provided that an end of the sun gear facing away from the first motor shaft is mounted by means of the freewheel. For example, the freewheel can mount the sun gear on the housing of the planetary gear. The freewheel can seal the housing there together with the sun gear. The housing can then be designed particularly simply. In addition, the housing can then have, for example, an axially continuous through-opening through which the first motor shaft is connected to the planetary gear. The freewheel is arranged, for example, axially in the direction of the first drive motor or axially in the direction of the output shaft next to the planetary gear. The freewheel can, for example, be arranged axially on a side of the sun gear or the sun shaft element facing away from the first drive motor.

[0043] Alternatively or additionally, the first motor shaft can be mounted by means of the freewheel, for example, on a motor housing of the first drive motor. For this purpose, a ball bearing can be replaced by the freewheel, for example, allowing the drive train to have fewer components and / or be particularly compact. For example, the respective cylinders of the first drive motor can be accommodated in the motor housing.

[0044] In one embodiment of the drive train, the output shaft can be arranged axially between the planetary gear and the first drive motor. This allows for an axial design for a single-track motor vehicle to enable better use of installation space.

[0045] In one embodiment of the drive train, it can be provided that the output shaft is arranged axially next to the planetary gear on a side of the planetary gear facing away from the first drive motor. This allows the first motor shaft to be particularly short and the distance between the first drive motor and the planetary gear to be small. In one embodiment of the drive train, it can be provided that the first motor shaft is permanently connected to the sun gear in a rotationally fixed manner. Alternatively or additionally, the second motor shaft can be permanently connected to the ring gear in a rotationally fixed manner. For example, the connection can be provided by a positive or frictional connection.

[0046] In one embodiment of the drive train, it can be provided that a flux barrier is arranged between a rotor of the electric motor and the ring gear. The flux barrier can, for example, be designed to shield a magnetic field. The flux barrier can, for example, be made of a non-ferromagnetic material. The flux barrier can be designed to redirect the magnetic field of the electric motor during operation. Alternatively or additionally, a non-ferromagnetic steel can be used for the ring gear to prevent the magnetic flux. The ring gear can then function, for example, as a flux barrier. The flux barrier can shield a magnetic field acting from the electric motor on the ring gear. As a result, the magnetic field of the electric motor in the planetary gear can be lower than in a design without a flux barrier.For example, the electric motor's magnetic field can no longer act on the planetary gear set at all. Unwanted forces, vibration losses, and iron losses caused by a magnetic flux through the rotating elements of the planetary gear and its planetary gears can thus be reduced or eliminated.

[0047] For example, the drive train has a mechanical power control for the first drive motor. For example, a throttle valve control can be provided, which is designed to adjust the torque of the first drive motor, which is designed as an internal combustion engine, at a predetermined speed. An operating speed is defined by means of the electric motor. Particularly preferably, the throttle valve control is implemented directly mechanically.

[0048] A direct mechanical throttle valve control can be provided, for example, by a Bowden cable. The throttle valve control can have an actuating element. The actuating element can be directly mechanically connected to the throttle valve for adjusting the throttle valve of the internal combustion engine. For example, the actuating element can be designed as a twist grip on the handlebars of the scooter or ATV. The actuating element can be designed to adjust a torque generated by the internal combustion engine, for example by controlling an air supply to the internal combustion engine. For this purpose, the actuating element can be connected to the throttle valve by means of the Bowden cable in the case of directly mechanical throttle valve control. In the internal combustion engine, for example, a generated torque can be changed by a driver by actuating the actuating element.Alternatively, the throttle valve can also be electronically controlled and adjusted, for example, depending on the operation of the control element by the driver.

[0049] This eliminates the need for signal monitoring, unlike an electrically controlled throttle valve. Furthermore, redundancy and plausibility checks are not required for the throttle valve control system to meet functional safety requirements.

[0050] The electric motor can, for example, be designed to be speed-controlled. The drive motor can have an inverter, by means of which the speed and / or power output of the electric motor can be adjusted. Torque control of the electric motor is also possible.

[0051] The electric motor can also be controlled by the actuating element. For example, the actuating element can have a sensor designed to detect a position of the actuating element. This position can be transmitted to the inverter. The inverter can be designed to control the electric motor depending on the detected position of the actuating element.

[0052] The drivetrain can be particularly simple and cost-effective if the throttle control actuator is also designed to control the electric motor. For example, using the scooter's twist grip, a throttle position can be set proportionally to the twist grip's rotational position and / or a control signal for the electric motor can be generated. The control signal can then be defined, for example, depending on an operating strategy, stored as a characteristic curve map, and / or an operating point. This also makes electrical control of the electric motor simple.

[0053] The drive train can have a charging controller. The charging controller can be formed as part of the electric motor. The charging controller can be formed by the inverter or can have the inverter. The charging controller can be designed to control the electric motor depending on a charge state of the energy storage device. For example, the charging controller can automatically charge the second energy storage device while the motor vehicle is traveling or reduce a speed and / or power output of the electric motor if the charge state falls below a threshold value. The charging controller can be designed to modify the control of the electric motor depending on the position of the actuating element according to the charge state of the energy storage device.For example, the charging control can modify a characteristic curve of the electric motor, which specifies its speed relative to the position of the actuating element, in particular by shifting it. This makes the control very simple, robust, and low in complexity. At a low state of charge, the overall torque of the drive train can be reduced compared to a high state of charge. This can signal a state of charge to the driver. The driver can also intuitively and easily compensate for this power reduction by adjusting the actuation. For example, the driver can turn the twist grip of the scooter further towards a higher drive power in order to achieve the desired power output even at a low state of charge. Compared to a high state of charge, a larger proportion of the power is then provided by the first drive motor.For example, no complex control system is required for this; instead, direct mechanical throttle valve control allows the driver to compensate accordingly through their control system. This can also ensure, for example, that sufficient residual charge remains to restart the combustion engine with the electric motor even after the journey has ended. Furthermore, the first energy storage device can also be used to power other systems in the motor vehicle without the risk of their failure due to the energy storage device being completely drained by the electric motor. The drive train can have a charging device designed to charge the first energy storage device with an energy source external to the vehicle. For example, the charging device can enable the energy storage device to be charged by connecting it to a national power grid.

[0054] For example, the freewheel and the shifting element each switch automatically. This means that the driver of the vehicle does not need to shift the planetary gear, making the vehicle extremely easy to operate. For example, the driver only has to steer, control the power output of both motors using a common actuating element, and brake if necessary. Further actions are not necessary to control the drive, in particular for driving the vehicle across its entire possible speed range. Furthermore, no actuators need to be provided for the freewheel and the shifting element, for example. The shifting element can therefore simply be integrated into the housing for the planetary gear. Likewise, no access is required to control the freewheel.The drive train can thus be easily retrofitted into existing basic vehicle concepts, even where space is limited.

[0055] A second aspect relates to a motor vehicle. The motor vehicle has a drive train according to the second aspect. Respective advantages and further features can be derived from the description of the first aspect, wherein embodiments of the first aspect also form embodiments of the second aspect and vice versa. Furthermore, the motor vehicle has an output element. The output element can be mechanically operatively connected to the output shaft of the drive train, in particular permanently connected in a rotationally fixed manner. The output element can be designed, for example, as a driven wheel, driven axle, or ship's propeller.

[0056] Short description of the characters

[0057] Fig. 1 schematically illustrates a drive train for a motor vehicle. Fig. 2 schematically illustrates a sectional view of part of a drive train for a motor vehicle.

[0058] Detailed description of embodiments

[0059] Fig. 1 schematically illustrates an embodiment of a drive train for a motor vehicle, which here is designed as a motor scooter, for example. Fig. 2 illustrates a further embodiment of a drive train for the motor vehicle designed as a scooter. In the following, the two embodiments are described together, since the basic concept of the two embodiments is the same. Differences are pointed out. Fig. 1 illustrates the overall basic concept of the drive train, while Fig. 2 illustrates a spatial arrangement and storage of the components of the drive train. This spatial arrangement and storage of the components of the drive train can also be applied to the differences in the drive train described in relation to Fig. 1.

[0060] The drive train is designed to drive a rear wheel 28 as the output element of the scooter. The drive train comprises a first drive motor 10 with a first motor shaft 12, a second drive motor 14 with a second motor shaft 16, a planetary gear 20, an output shaft 22, a shifting element 24, and a freewheel 26. The planetary gear 20 comprises a planetary gear set 30 with a sun gear 32, a planet carrier 34, and a ring gear 36. Rotatably mounted on the planet carrier 34 are several planetary gears 38, each of which meshes with the sun gear 32 and the ring gear 36.

[0061] In the embodiment shown in Fig. 1, the first motor shaft 12 is mechanically operatively connected to the sun gear 32 by means of a chain 40, gears, a belt, or generally a reduction gear. In the embodiment shown in Fig. 2, this operative connection is omitted, and the first motor shaft 12 is permanently and non-rotatably connected directly to the sun gear 32. The first drive motor 10 in both embodiments is designed as an internal combustion engine. The sun gear 32 thus forms a first input shaft of the planetary gear 20. The second motor shaft 16 is mechanically connected to the ring gear 36 via a spur gear stage 42 in the embodiment shown in Fig. 1. In the embodiment shown in Fig. 2, this operative connection is omitted, and the second motor shaft 16 is permanently and non-rotatably connected directly to the ring gear 36. The second drive motor 14 is designed as an electric motor in both embodiments. The ring gear 36 thus forms a second input shaft of the planetary gear 20.

[0062] The planet carrier 34 is permanently connected to the output shaft 22 in a rotationally fixed manner. The planet carrier 34 thus forms an output shaft of the planetary gear 20. The output shaft 22 can, for example, be directly connected to the output element of the motor vehicle, in this case the rear wheel 28, in a rotationally fixed manner. The output shaft 22 can also be mechanically operatively connected to the output element or the rear wheel 28. Fig. 2 shows that the output shaft 22 can, for example, be designed as a pinion, which is permanently attached to the planet carrier 34 in a rotationally fixed manner. The rear wheel 28 is then mechanically operatively connected to the output shaft 22, for example, via a chain or a belt.

[0063] The planetary gear set 30 can be locked in place by means of the shifting element 24. In the embodiment of Fig. 1, the shifting element 24 is designed to connect the sun gear 32 to the ring gear 36 in a rotationally fixed manner. In an alternative embodiment, the shifting element 24 is designed to connect the planet carrier 34 to the sun gear 32 in a rotationally fixed manner. In yet another alternative embodiment, the shifting element 24 is designed to connect the planet carrier 34 to the ring gear 36 in a rotationally fixed manner. In the embodiment of Fig. 2, the shifting element 24 is designed to connect the planet carrier 34 to the ring gear 36 in a rotationally fixed manner. The shifting element 24 is designed, for example, as an automatically switching element which locks the planetary gear set 30 as a function of a rotational speed. In Fig. 2, it can be seen that the shifting element 24 is designed as a centrifugal clutch. If a limiting rotational speed of the planet carrier 34 orof the output shaft 22, the switching element 24 connects the planet carrier 34 in a rotationally fixed manner to the ring gear 36. In the embodiment of Fig. 2, movable parts of the switching element 24 are mounted on the planet carrier 34. The freewheel 26 is designed to lock the first motor shaft 12 or the sun gear 32. The freewheel 26 prevents the first motor shaft 12 or the sun gear 32 from rotating backwards. Rotation in a forward direction, however, is permitted by the freewheel 26. The freewheel 26 also forms an automatically switching switching element which can connect the first motor shaft 12 or the sun gear 32 to a stationary component, such as a housing, in a rotationally fixed manner. Alternatively, instead of the freewheel 26, an actively switchable switching element is provided, by means of which the first motor shaft 12 or the sun gear 32 can be selectively locked.

[0064] In the embodiment according to Fig. 1, the second drive motor 14 with its second motor shaft 16 is arranged axially parallel to the sun gear 32 due to the spur gear stage 42. Likewise, in this embodiment, the first drive motor 10 with its first motor shaft 12 can be arranged axially offset from the sun gear 32 due to the chain 40. In this embodiment, the rear wheel 28 is arranged coaxially to the sun gear 32.

[0065] In the embodiment shown in Fig. 2, the first sun gear 32, the first motor shaft 12, and the second motor shaft 16 are arranged coaxially with one another. In the second embodiment, this results in a compact arrangement, mounting, and design of the drive train, which is explained in detail below. The rear wheel 28 can be arranged coaxially or axially offset from the sun gear 32. An axis of rotation of the rear wheel 28 can be aligned parallel or transversely to the sun gear 32. For example, the sun gear 32 extends through the motor vehicle in the transverse direction of the vehicle.

[0066] As can be seen in Fig. 2, the drive train has a housing 50 in which the second drive motor 14 and the planetary gear set 20 are accommodated. The second drive motor 14 is designed as an internal rotor. The housing 50 is attached, for example, to a stationary component of the first drive motor 10 or of the motor vehicle. A stator 52 of the second drive motor 14 is mounted on the housing 50 in a rotationally fixed manner. A rotor 54 forms the second motor shaft 16 and is mounted on the ring gear 36 by a permanent rotationally fixed connection to the ring gear 36. The second drive motor 14 is arranged radially outwardly of the planetary gear set 20 and in particular of the planetary gear set 30. The second drive motor 14 thus radially encloses the planetary gear set 30 and has a large diameter, whereby the second drive motor 14 can have a very high torque.

[0067] The ring gear 36 is mounted on the sun gear 32 by means of a first bearing 60 and on the planet carrier 34 by means of a second bearing 62. The first bearing 60 is mounted on the sun gear 32 on a side of the planetary gear set 30 facing the first drive motor 10. The second bearing 62 is mounted on the planet carrier 34 on a side of the planetary gear set 30 facing away from the first drive motor 10. A toothing of the rotating elements of the planetary gear set 30 and the planet gears 38 extends axially between the first bearing 60 and the second bearing 62. As can also be seen, the ring gear 36 extends axially on both sides radially inward past the planet gears 38 to the first bearing 60 and the second bearing 62. The first bearing 60 and the second bearing 62 are designed, for example, as ball bearings.

[0068] The planet carrier 34 is mounted on the sun gear 32 by means of a third bearing 64 and a fourth bearing 66. The third bearing 64 and the fourth bearing 66 are mounted on the sun gear 32 on a side of the planet gears 38 and the gear teeth of the rotating elements of the planetary gear set 30 that is axially remote from the first drive motor 10. The third bearing 64 is designed, for example, as a ball bearing. The fourth bearing 66 is designed, for example, as a needle bearing in order to provide more radial installation space for the output shaft 22.

[0069] The ring gear 36 and the planet carrier 34 are thus mounted directly on the sun gear 32 as the central main bearing shaft, and the rotor 54 is mounted indirectly via the ring gear 36. The sun gear 32 is mounted on one end of the first motor shaft 12, which is designed here as a crankshaft. For example, the sun gear 32 is permanently and non-rotatably fastened to the first motor shaft 12 by means of a conical press fit, as shown. Alternatively, the sun gear 32 can be fastened to the first motor shaft 12, for example, with a cylindrical press fit or a screw connection. The first motor shaft 12 is mounted, for example, with two additional bearings in the internal combustion engine or on a stationary component of the motor vehicle. As a result, a total of only six bearings are required to support the respective rotating parts of the drive train. An axial end of the sun gear 32 facing away from the first drive motor 10 can be free.In the example shown, the axial end of the sun gear 32 facing away from the first drive motor 10 is mounted on the housing 50 by means of the freewheel 26. This allows for a low load on the first motor shaft 12. Furthermore, the freewheel 26 can be designed as a sealed bearing and close the housing 50 with the sun gear 32 on this side. A seal can be provided between the housing 50 and the first motor shaft 12 and / or the sun gear 32 on a side axially opposite this side.

[0070] The switching element 24 is arranged radially between the ring gear 36 and the planet carrier 34 in the same axial region as the ring gear 36 and the planet carrier 34. This allows the drive arrangement to be particularly compact. The switching element 24 is arranged next to the toothing of the respective rotating elements and the planet gears 38 on a side axially facing away from the first drive motor 10. The output shaft 22 is also arranged next to the toothing of the respective rotating elements and the planet gears 38 on a side axially facing away from the first drive motor 10. This allows a connection between the planetary gear 20 and the first drive motor 10 to be particularly short axially. The output shaft 22 is arranged next to the switching element 24 on a side of the switching element 24 axially facing away from the planetary gear set 30. This makes the output shaft 22 particularly easy to access and the ring gear 36 can be axially short.

[0071] Alternatively, the shifting element 24 can be arranged axially next to the toothing of the respective rotating elements and the planetary gears 38 on a side facing the first drive motor 10. Alternatively, the output shaft 22 can be arranged axially next to the toothing of the respective rotating elements and the planetary gears 38 on a side facing the first drive motor 10. This allows the planetary gear 22 to be retrofitted particularly easily to single-track motor vehicles.

[0072] The second drive motor 14 extends axially from a first axial end facing the first drive motor 10 to a second axial end opposite thereto and facing away from the first drive motor 10. The toothing of the respective rotating elements and the planetary gears 38 of the planetary gear set 30 extends between these two axial ends of the second drive motor. The planetary gear set 30 does not extend axially in the direction of the first drive motor 10 beyond the first axial end of the second drive motor 14. The planetary gear 20 and the second drive motor 14 therefore extend at least partially in the same axial region.

[0073] The planetary gears 38 are rotatably mounted on a pin 72 of the planetary carrier 34 by means of a further bearing 70. In the second embodiment, the rear gear 28 is arranged, for example, axially offset from the sun gear 32, whereby the housing 50 does not have to be installed in the motor vehicle next to the rear wheel 28 in the transverse direction of the vehicle. This allows for particularly simple integration of the drive train.

[0074] Reference symbol

[0075] 10 first drive motor

[0076] 12 first motor shaft

[0077] 14 second drive motor

[0078] 16 second motor shaft

[0079] 20 planetary gears

[0080] 22 Output shaft

[0081] 24 switching element

[0082] 26 Freewheel

[0083] 28 rear wheel

[0084] 30 planetary gear set

[0085] 32 Sun gear

[0086] 34 planet carriers

[0087] 36 ring gear

[0088] 38 planetary gears

[0089] 40 chain

[0090] 42 spur gear stage

[0091] 50 housings

[0092] 52 Stator

[0093] 54 Rotor

[0094] 60 first camp

[0095] 62 second camp

[0096] 64 third camp

[0097] 66 fourth camp

[0098] 70 warehouses

[0099] 72 bolts

Claims

Patent claims 1 . Drive train for a motor vehicle, wherein the drive train comprises at least a first drive motor (10) with a first motor shaft (12), a second drive motor (14) with a second motor shaft (16), a planetary gear (20), an output shaft (22) and a shifting element (24), wherein the second drive motor (14) is designed as an electric motor, wherein the planetary gear (20) comprises a planetary gear set (30) with a sun gear (32), a planet carrier (34) and a ring gear (36), wherein the first motor shaft (12) is mechanically operatively connected to the sun gear (32), wherein the second motor shaft (16) is mechanically operatively connected to the ring gear (36), wherein the planet carrier (34) is permanently connected in a rotationally fixed manner to the output shaft (22), wherein the planetary gear set (30) is blockable by means of the shifting element (24), and wherein the first sun gear (32), the first motor shaft (12) and the second motor shaft (16) are arranged coaxially to each other.

2. Drive train according to claim 1, wherein the electric motor (14) is designed as an internal rotor and is arranged radially outwardly of the planetary gear (20), in particular wherein the planetary gear (20) and the electric motor (14) are arranged in a same axial region.

3. Drive train according to claim 1 or 2, wherein the switching element (24) is designed as an automatically switching switching element, in particular as a centrifugal clutch.

4. Drive train according to one of the preceding claims, wherein the switching element (24) is arranged radially between two rotating elements of the planetary gear (20), which can be connected to one another in a rotationally fixed manner by means of the switching element (24).

5. Drive train according to one of the preceding claims, wherein the switching element (24) is arranged axially next to the planetary gear (20) and / or the output shaft (22).

6. Drive train according to one of the preceding claims, wherein the planet carrier (34) is mounted on the sun gear (32) and / or wherein the ring gear (36) is mounted on the sun gear (32).

7. Drive train according to one of the preceding claims, wherein the drive train has a freewheel (26) by means of which the first motor shaft (12) can be fixed, in particular wherein an end of the sun gear (32) facing away from the first motor shaft (12) is mounted by means of the freewheel (26) and / or wherein the first motor shaft is mounted on a motor housing of the first drive motor by means of the freewheel.

8. Drive train according to one of the preceding claims, wherein the output shaft (22) is arranged axially between the planetary gear (20) and the first drive motor (10) or wherein the output shaft (22) is arranged axially next to the planetary gear (20) on a side of the planetary gear (20) facing away from the first drive motor (10).

9. Drive train according to one of the preceding claims, wherein the first motor shaft (12) is permanently connected to the sun gear (32) in a rotationally fixed manner and / or wherein the second motor shaft (16) is permanently connected to the ring gear (36) in a rotationally fixed manner.

10. Drive train according to one of the preceding claims, wherein a flux barrier is arranged between a rotor (54) of the electric motor (14) and the ring gear (36) or the ring gear (36) is designed as a flux barrier in order to shield a magnetic field acting from the electric motor (14) on the ring gear (36).

11. Motor vehicle with a drive train according to one of the preceding claims and an output element, wherein the output element is mechanically operatively connected to the output shaft (22) of the drive train.

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