DE102021109279A1 - Switching unit for coupling an auxiliary unit to a drive train and drive arrangement with the switching unit - Google Patents

Abstract

A switching unit 14 for coupling an auxiliary unit 13 to a drive train of a motor vehicle, with an input shaft section 15 for the drive connection to the drive train, with an output shaft section 16 for the drive connection to the auxiliary unit 13, with a planetary gear 24 for translating a drive speed from the input shaft section 15 to the output shaft section 16, with the input speed in a first switching state of the switching unit 14 in a first transmission ratio and in a second switching state of the switching unit 14 in a second transmission ratio different from the first transmission ratio from the input shaft section 15 via the planetary gear 24 to the output shaft section 16 is transferrable, proposed, with a speed-dependent switching arrangement 29, wherein the switching arrangement 29 is formed, the switching unit 14 depending on the drive speed between automatically switch between the first switching state and the second switching state.

Description

The invention relates to a switching unit for coupling an auxiliary unit to a drive train of a motor vehicle, having the features of the preamble of claim 1. The invention also relates to a drive arrangement for a motor vehicle with the switching unit.

In conventional motor vehicles, which are driven exclusively by an internal combustion engine, the ancillary units of the vehicle, such as the air conditioning compressor, water pump, power steering pump, generator or similar, are connected to the internal combustion engine via chains, belts or gears. With increasing hybridization or electrification of the drive train, the ancillary units can be mechanically connected to the vehicle transmission in order to be able to be driven at least indirectly by the vehicle's drive engine.

For example, the reference discloses DE 10 2017 128 431 A1 of the applicant, a switching unit for coupling an auxiliary unit to a drive train of a motor vehicle, comprising a carrier element guided on an at least indirectly driven shaft, a clutch element that can be displaced in the axial direction parallel to the shaft, and a planetary gear, via which the shaft is connected to at least two different power transmission paths can be connected to the ancillary unit, wherein a speed of the shaft can be transmitted to the ancillary unit in a first switching position of the switching unit in a first transmission ratio and in a second switching position of the switching unit to the ancillary unit in a second transmission ratio that differs from the first transmission ratio.

It is an object of the invention to propose a switching unit for coupling an auxiliary unit to a drive train, which is characterized by an improved switching concept.

This object is achieved by a switching unit having the features of claim 1 and a drive assembly having the features of claim 10. Preferred or advantageous embodiments of the invention result from the dependent claims, the following description and the attached figures.

The subject matter of the invention is a switching unit which is designed and/or suitable for coupling an auxiliary unit to a drive train of a motor vehicle. In particular, the ancillary unit can be designed as an air conditioning compressor, a water pump, a power steering pump, a generator or a pump for a coolant circuit routed via a battery assembly. Alternatively, the ancillary unit can also be in the form of an internal combustion engine or an electric motor.

The switching unit has an input shaft section which is designed and/or suitable for the drive-related connection to the drive train. In principle, the input shaft section can be connected directly to a drive shaft of the drive train. For example, the input shaft section can form a section of the drive shaft for this purpose or at least be connected to the drive shaft in a rotationally fixed manner. Alternatively, the input shaft section can be connected to the drive shaft via a transmission unit, the transmission unit being designed and/or suitable for transmitting and/or converting the drive torque from the drive shaft to the input shaft section.

The switching unit has an output shaft section which is designed and/or suitable for the drive-related connection to the auxiliary unit. In particular, the output shaft section forms a drive shaft for the auxiliary unit. The output shaft section and the input shaft section are preferably arranged coaxially to one another with respect to a main axis of rotation.

The switching unit also has a planetary gear which is designed and/or suitable for converting a drive speed from the input shaft section to the output shaft section. In particular, the input shaft section forms a transmission input of the planetary gear and the output shaft section forms a transmission output of the planetary gear. In particular, the switching unit is designed as a two-speed switching unit, in particular a two-speed transmission, which can be switched between a first and a second switching state. In the first switching state, the drive speed can be transmitted in a first transmission ratio from the input shaft section to the output shaft section via the planetary gear. In the second switching state, the drive speed can be transmitted in a second transmission ratio, which is different from the first transmission ratio, from the input shaft section to the output shaft section via the planetary gear.

The invention provides that the switching unit has a speed-dependent switching arrangement which is designed to automatically switch the switching unit between the first switching state and the second switching state as a function of the drive speed. In particular, the switching arrangement has the function that To switch switching unit automatically from one to the other switching state when a predetermined limit speed is reached on the input shaft. In particular, “automatically” is to be understood to mean that the switching arrangement switches the first and the second switching state by itself or without external influence as a function of the rotational speed.

An essential advantage of the invention is that the speed-dependent switching arrangement means that no externally actuated actuator is required to switch the switching unit. The switching unit can thus be implemented in a particularly simple and cost-effective manner. In addition, such a switching unit is characterized by a robust construction. Another advantage is that the efficiency of the overall system can be increased by connecting the ancillary unit to the drive train via the switching unit, since the speed of the ancillary unit is automatically adjusted from a certain limit speed of the drive engine due to the different transmission ratios of the two switching states.

In a specific implementation, it is provided that the drive speed in the first shifting state is translated to the output shaft section via the planetary gear, so that in the first shifting state an output speed at the output shaft section is different from the drive speed at the input shaft section. In particular, the output shaft section has a higher rotational speed than the input shaft section in the first switching state. In other words, in the first switching state, the planetary gear has a transmission ratio in relation to the rotational speed of i<1. Alternatively, however, the output shaft section can also have a lower rotational speed than the input shaft section in the first switching state. In other words, in the first switching state, the planetary gear has a transmission ratio in relation to the rotational speed of i>1.

Furthermore, it is provided that the input speed in the second switching state is transmitted directly to the output shaft section via the planetary gear, so that in the second switching state an output speed at the output shaft section is equal to the input speed at the input shaft section. In other words, in the second switching state, the planetary gear has a transmission ratio of i=1 in relation to the rotational speed. The switching unit is preferably switched from the first to the second switching state when the speed limit is exceeded, and is switched again from the second switching state to the first switching state if the speed falls below the limit speed. The planetary gear is preferably in a transmission mode in the first switching state and in a block mode in the second switching state. As a result, the power of the auxiliary unit can be adjusted according to the required power in order to optimize the efficiency of the auxiliary unit as the speed of the drive engine increases.

In a further embodiment it is provided that the planetary gear has a ring gear, a planet carrier, a planetary gear set and a sun gear. The planet gears are rotatably mounted in the planet carrier and are in engagement with the sun gear on the one hand and with the ring gear on the other hand.

In particular, the planet carrier is non-rotatably connected to the input shaft section and the sun gear is non-rotatably connected to the output shaft section. Alternatively, however, the planet carrier can also be connected in a rotationally fixed manner to the output shaft section and the sun gear can be connected in a rotationally fixed manner to the input shaft section. In particular, the switching unit has a housing for accommodating the planetary gear, with the housing being formed or also formed by a housing section. The planetary gear is preferably arranged in the housing, with the input shaft section being guided into the housing on one side and the output shaft section being guided out of the housing on the other side. In particular, the switching unit can be designed as a preassembled structural unit.

The switching arrangement has a first coupling device for the non-rotatable coupling of the ring gear to the housing section and a second coupling device for the non-rotatable coupling of the planet carrier to the output shaft section or the input shaft section. In particular, the first and the second coupling device can each be switched between a coupling position and a release position. In the first switching state, the ring gear is coupled to the housing section by the first coupling device and the planetary carrier is decoupled from the output shaft section or the input shaft section by the second coupling device. In particular, the first coupling device is switched to the coupled position and the second coupling device is switched to the release position. A torque path preferably runs from the input shaft section via the planetary carrier, the planet wheels and the sun wheel to the output shaft section. Alternatively, the torque path runs from the input shaft section via the sun wheel, the planet wheels and the planet carrier to the output shaft section. In the second switching state, the ring gear is separated from the housing by the first coupling device Section decoupled and the planet carrier is coupled by the second coupling device with the output shaft section. In particular, the first coupling device is switched to the release position and the second coupling device is switched to the coupled position. A torque path preferably runs from the input shaft section via the planet carrier to the output shaft section.

In a specific development, it is provided that one coupling device is designed as a centrifugal device and the other coupling device is designed as a freewheel device. In particular, the centrifugal device can be switched automatically between the coupling position and the release position as a function of the drive speed. In particular, the freewheel device can be switched automatically between the coupling position and the release position depending on a direction of rotation. Preferably, when the limit speed is exceeded, the centrifugal device is actuated due to increasing centrifugal forces, with actuation of the centrifugal device reversing the direction of rotation in the planetary gear and at the same time the freewheel device is actuated due to the changed direction of rotation. A switching arrangement is thus proposed which is characterized by a purely mechanical configuration and at the same time can switch the switching unit automatically as a function of the speed.

In a first specific embodiment, it is provided that the first coupling device is designed as the centrifugal device and the second coupling device as the freewheel device, with the centrifugal device being switched to the coupled position and the freewheeling device to the release position in the first switching state, and the centrifugal device being switched to the second switching state is switched in the release position and the freewheel device in the coupling position. In regular operation, the drive torque is transmitted to the planetary gears via the planetary carrier in the first switching state, with the planetary gears rolling on the stationary ring gear and the drive torque being transmitted via the sun gear to the output shaft section. If the limit speed on the input shaft section or the planetary carrier is exceeded, the centrifugal device is actuated and the ring gear is decoupled from the housing section. The lack of fixation of the ring gear results in a reversal of the direction of rotation in the planetary gear set, as a result of which the freewheel device is actuated and couples the planet carrier to the output shaft section in a torque-proof manner. From this point in time, the switching unit is in the second switching state, with the drive torque being transmitted directly to the output shaft section via the planetary carrier.

In a second specific embodiment, it is provided that the first coupling device is configured as the freewheel device and the second coupling device as the centrifugal force device, with the freewheel device being switched in the coupling position and the centrifugal force device in the release position in the first switching state, and the freewheeling device being switched in the second switching state is switched in the release position and the centrifugal device in the coupling position. In regular operation, the drive torque is transmitted to the planetary gears via the planetary carrier in the first switching state, with the planetary gears rolling on the stationary ring gear and the drive torque being transmitted via the sun gear to the output shaft section. If the limit speed on the input shaft section or the planet carrier is exceeded, the centrifugal device is actuated and the planet carrier is coupled to the output shaft section. By fixing the planet carrier to the output shaft section, the direction of rotation in the planetary gear set is reversed, as a result of which the freewheel device is actuated and the ring gear is decoupled from the housing section. From this point in time, the switching unit is in the second switching state, with the drive torque being transmitted directly to the output shaft section via the planetary carrier.

In a further specification, it is provided that the centrifugal force device has a braking section and an actuating section, with the actuating section being designed to transmit an axial actuating force to the braking section as a function of the rotational speed. In particular, the actuating section is operatively connected to the input shaft section and/or the planetary carrier, so that the centrifugal device is actuated as a function of the input speed. The braking section can be designed as a form-fitting and/or friction-fitting clutch, which is open in the freewheeling position and closed in the coupled position. In particular, the coupling position forms a basic position in which a braking torque is generated by the braking section. A centrifugal device is thus proposed which is characterized by simple actuation and at the same time can be easily integrated into the switching unit.

In a further specific implementation, it is provided that the braking section has a first and a second braking partner, the two braking partners being connected to one another in the coupled position and being rotatable relative to one another in the release position. In particular, according to the first embodiment variant, one brake partner is connected to the ring gear and the other brake partner is connected to the housing section at least non-rotatably connected. Alternatively, according to the second embodiment variant, one braking partner is connected to the planetary carrier and the other braking partner is connected at least in a rotationally fixed manner to the output shaft section. The braking section can be designed as an axially actuated disk clutch, with the two braking partners each being designed as disk carriers. Alternatively, the braking section can be designed as an axially actuatable claw clutch, with the two braking partners each being designed as a claw shoe. Particularly preferably, the two brake sections can be moved relative to one another in an axial direction, in particular in relation to the main axis of rotation. In particular, the braking section has at least one spring element which is designed to apply a spring force to the two braking partners in the coupling position/basic position. When actuated, the actuating force acts against the spring force, so that the two braking sections are transferred from the coupled position/basic position to the release position. A centrifugal device is thus proposed which is characterized by a robust structure and simple operation.

In a further specific embodiment, it is provided that the centrifugal device has an axial bearing. In particular, the axial bearing is used for the axial mounting of the actuating section relative to the braking section. For this purpose, the axial bearing is arranged axially between the braking section and the actuating section, the actuating force being transferrable from the actuating section to the braking section via the axial bearing. The axial bearing is preferably designed as a roller bearing, e.g. an axial needle bearing. The axial bearing can ensure relative rotation between the braking section and the actuating section, with the actuating force being able to be transmitted to the actuating section via the axial bearing at the same time.

Another object of the invention relates to a drive arrangement for a motor vehicle with a drive motor for generating a drive torque. In principle, the drive motor is designed as an electric motor. Alternatively, however, the drive motor can also be designed as an internal combustion engine. The drive motor is drivingly connected to a drive shaft to transmit the drive torque, the drive shaft being connected at least indirectly to a differential gear to distribute the drive torque to a first and a second output shaft. In particular, it is to be understood, at least indirectly, that the drive shaft is either directly operatively connected to the differential gear or is operatively connected to the differential gear via at least one intermediate gear.

According to this embodiment, the drive shaft or at least one intermediate shaft arranged in the power flow between the drive shaft and the differential gear can be connected to an auxiliary unit via a switching unit, as already described above. In particular, the input shaft section is connected to the drive shaft or, if applicable, the intermediate shaft for this purpose. The input shaft section of the switching unit can be connected directly, in particular in a torque-proof manner, to the drive shaft or the intermediate shaft, or form a section thereof. Alternatively, the input shaft section can be connected to the drive shaft or the intermediate shaft via the at least one transmission unit.

Optionally, additionally, a clutch device is provided between the drive shaft and the differential gear, which is designed to interrupt a torque transmission between the drive motor and the differential gear. This makes it possible for the ancillary unit to also be operated while the vehicle is stationary. Alternatively or optionally in addition, a further clutch device can be provided between the switching unit and the auxiliary unit or between the switching unit and the drive motor in order to interrupt torque transmission between the drive motor and the auxiliary unit. This means that the ancillary unit does not have to be lugged around when it is not needed. The power loss of the drive train can thus be reduced and the range of the motor vehicle can be increased.

• 1 eine schematische Darstellung einer Antriebsanordnung für ein Fahrzeug als ein erstes Ausführungsbeispiel der Erfindung;
• 2 die Antriebsanordnung in gleicher Darstellung wie 1 als ein zweites Ausführungsbeispiel der Erfindung;
• 3 eine schematische Darstellung einer alternativen Antriebsanordnung für ein Fahrzeug als drittes Ausführungsbeispiel der Erfindung;
• 4 eine Schalteinheit der Antriebsanordnungen gemäß der 1 bis 3 in einem ersten Schaltzustand;
• 5 die Schalteinheit in gleicher Darstellung wie in 4 in einem zweiten Schaltzustand;
• 6 eine alternative Ausführung der Schalteinheit in einem ersten Schaltzustand;
• 7 die Schalteinheit in gleicher Darstellung wie in 6 in einem zweiten Schaltzustand.

Further features, effects and advantages of the invention result from the following description of a preferred exemplary embodiment of the invention and the attached figures. show:

• 1 a schematic representation of a drive arrangement for a vehicle as a first embodiment of the invention;
• 2 the drive arrangement in the same representation as 1 as a second embodiment of the invention;
• 3 a schematic representation of an alternative drive arrangement for a vehicle as a third embodiment of the invention;
• 4 a switching unit of the drive assemblies according to 1 until 3 in a first switching state;
• 5 the switching unit in the same representation as in 4 in a second switching state;
• 6 an alternative embodiment of the switching unit in a first switching state;
• 7 the switching unit in the same representation as in 6 in a second switching state.

the 1 until 2 each show a schematic representation of a drive arrangement 1 for a motor vehicle. The drive arrangement 1 has a drive motor 2 , in particular an electric motor, which is drive-connected to a drive shaft 3 . The drive shaft 3 has a drive wheel section 4, for example a gear wheel, which is in engagement with an intermediate wheel section 5, for example another gear wheel, of an intermediate shaft 6.

The intermediate shaft 6 is connected to a differential gear 8 of the motor vehicle via an intermediate gear 7 . For example, the intermediate gear 7 is designed as a single-stage reduction gear. The intermediate gear 7 has an output gear section 9 that can be connected to the intermediate shaft 6 in a torque-proof manner, which can be connected in a torque-proof manner to the intermediate shaft 6 via a clutch device 10 and is connected to the differential gear 8 in terms of transmission technology. For example, the driven wheel section 9 is designed as a loose wheel, which is arranged coaxially to the intermediate shaft 6 and/or is mounted on the intermediate shaft 6 . The differential gear 8 distributes the drive torque of the drive motor 2 to a first and a second output shaft 11, 12, which are each connected to at least one driven wheel of the motor vehicle.

The drive arrangement 1 also has an auxiliary unit 13, which can be designed, for example, in the form of a power steering pump, an air conditioning compressor or a pump for a coolant circuit routed via a battery assembly. Alternatively, the ancillary unit 13 can also be an internal combustion engine (DHT transmission) or another electric motor (e-CVT transmission).

In the course of the increasing hybridization or electrification of vehicles, fewer and fewer vehicles will be equipped with a FEAD (Front End Accessory Drive) in the future, via which the ancillary units are driven by the internal combustion engine according to the state of the art. It is therefore proposed to connect the ancillary unit 13 to the drive train of the vehicle via a two-speed shift unit 14 so that the ancillary unit 13 can be driven by the drive motor 2 .

The switching unit 14 has an input shaft section 15 and an output shaft section 16, with the switching unit 14 being operatively connected to the drive motor 2 via the input shaft section 15 on the drive side and being operatively connected to the auxiliary unit 13 via the output shaft section 16 on the output side. The switching unit 14 can optionally be connected to the drive shaft 3 via the input shaft section 15, as in 1 shown, or the intermediate shaft 6, as in 2 shown to be connected.

The drive arrangement 1 optionally has a transmission unit 17 via which the input shaft section 15 is connected to the drive shaft 3 or the intermediate shaft 6 . For example, the transmission unit 17 in the embodiments shown 1 and 2 designed as a spur gear to allow the required speed ratios on the auxiliary unit 13.

For example, the ancillary unit is designed as an air conditioning compressor, with the air conditioning compressor being able to be designed as a mechanically driven axial piston compressor due to the connection to the drive train. The axial piston compressor with a mechanical connection to the drive train has the advantage over an electrically driven scroll compressor that it can be operated more efficiently in terms of consumption, which means that the range can be improved, especially in electric vehicles. In addition, such a system is less expensive with less weight and without the need for high-voltage components.

the 3 shows an alternative embodiment of a drive arrangement 1 for a motor vehicle. The drive arrangement 1 has a drive motor 2, in particular an electric motor, and a further drive motor 18, in particular an internal combustion engine, with the drive motor 2 driving a drive shaft 3 and the further drive motor 18 driving a further drive shaft 19.

The further drive shaft 19 can be drive-connected to the drive shaft 2 via a clutch device 10, in particular a separating clutch (KO clutch), in order to switch the drive train between purely electric operation and hybrid operation. This means that the electric motor can also be used independently of the combustion engine for purely electric driving. The drive shaft 2 is also connected via a further clutch device 20, in particular a dual clutch (K1/K2 clutch), to an intermediate transmission 16, in particular a dual clutch transmission, with the electrical or summed drive torque being transmitted via a first and/or second Sub-transmission 21, 22 is transmitted to an output shaft 23.

In this special embodiment, the switching unit 14 has to be connected to the electric drive motor 2 via the drive shaft 3 in order to drive the auxiliary unit 13 . For this purpose, the drive shaft 3 is drivingly connected to the input shaft section 15 via the transmission unit 17 . For example, the transmission unit 17 in this embodiment can be designed as a traction mechanism, e.g. a chain or belt drive.

So that the ancillary unit 13 can also be operated while the vehicle is stationary, it is advantageous if the drive motor 2 can be decoupled from the drive train or the wheels. This is like in the 1 until 3 shown versions possible via the clutch device 10, which is installed in most transmission concepts such as P2-DCT, DHT or P2-AT.

the 4 and 5 each show the switching unit 14 in a schematic representation. The switching unit 14 is designed as a switchable two-speed transmission, the switching unit 14 being switchable between a first and a second switching state with different gear ratios. 4 shows the switching unit 14 in the first switching state and 5 in the second switching state.

The switching unit 14 has a planetary gear 24 , the input shaft section 15 forming a transmission input and the output shaft section 16 forming a transmission output of the planetary gear 24 . The planetary gear 24 has a sun gear 25, a ring gear 26, a planetary carrier 27 and a planetary gear set consisting of a plurality of planetary gears 28. The planet carrier 27 is non-rotatably connected to the input shaft section 15 and the sun gear 25 is non-rotatably connected to the output shaft section 16 . The planetary carrier 27 carries the plurality of planet gears 28 which are in mesh with the sun gear 25 on the one hand and with the ring gear 26 on the other hand.

The switching unit 14 also has a switching arrangement 29 which is set up to automatically switch the switching unit 14 between the first and the second switching state depending on the rotational speed. For this purpose, the switching arrangement 29 has a first and a second coupling device 30, 31, the first and the second coupling device 30, 31 each switching independently between a release position and a coupling position.

The first coupling device 30 is arranged between the ring gear 26 and a housing section 32 of a housing (not shown) of the switching unit 14, the first coupling device 30 in the coupled position coupling the ring gear 26 to the housing section 32 in a torque-proof manner and in the release position the ring gear 26 relative to the housing section 32 releases.

The second coupling device 31 is arranged between the output shaft section 16 and the planetary carrier 27, the second coupling device 31 in the coupled position coupling the planetary carrier 27 to the output shaft section 16 in a torque-proof manner and in the release position the output shaft section 16 is released relative to the planetary carrier 27.

In the exemplary embodiment shown, the first coupling device 30 is designed as a centrifugal device in order to automatically switch the first coupling device 30 as a function of a speed. For this purpose, the first coupling device 30 has an actuating section 33 and a braking section 34, with the actuating section 33 being set up to transmit an axial actuating force 35 to the braking section 34 when a predetermined limit speed is exceeded. For this purpose, the actuating section 33 is connected to the input shaft section 15

The braking section 34 has a first and a second braking partner 36, 37, which are positively and/or non-positively engaged in the coupling position and are disengaged in the release position. The first brake partner 36 is non-rotatably connected to the ring gear 26 and the second brake partner 37 is non-rotatably connected to the housing section 32, the two brake partners 36, 37 being movable relative to one another in the axial direction. For example, the braking section 34 is designed as an axially actuated dog clutch or an axially actuated disk pack.

The actuating section 34 is supported in the axial direction via an axial bearing 38 on the braking section 34, in particular the first braking partner 34, with the axial bearing 38 serving to transmit the actuating force 35 to the braking section 34 and at the same time to transmit the actuating section 33 in the direction of rotation of the braking section 34 to decouple. For example, the axial bearing 38 is designed as an axial needle bearing.

The second coupling device 31 is designed as a freewheel device in order to automatically switch the second coupling device 31 depending on a direction of rotation. The freewheel device allows a relative rotation between the output shafts in one switching state Section 16 and the planet carrier 25 in one direction of rotation, whereas in the other switching state a rotational movement of the planet carrier 27 is transmitted to the output shaft section 16 in an opposite direction of rotation.

In one operating state, the input shaft section 15 is driven at a drive speed, with the first coupling device 30 being switched to the coupling position and the second coupling device 31 being switched to the release position in the first switching state. Ring gear 26 is blocked in its rotational movement, so that the drive torque introduced via input shaft section 15 is supported in the planetary gear set via housing section 32 and the drive speed is translated into a corresponding output speed at output shaft section 16 . A moment path runs as in 4 indicated, from the input shaft section 15 via the planet carrier 27, the planet wheels 28 and the sun wheel 25 to the output shaft section 16.

In particular, the switching unit 14 has a transmission ratio in relation to the speed of i<1 in the first switching state.

Above a certain limiting speed or as a function of the centrifugal force, the actuating section 33 generates the axial actuating force 35, which acts on the braking section 34 via the axial bearing 38 and switches the first coupling device 30 from the coupling position into the release position. For example, the brake section 34 is closed in the coupled position by means of a spring preload, with the actuating force 35 acting against the spring preload and separating the first and the second brake section 36, 37 from one another. The lack of fixation of the ring gear 26 results in a reversal of the direction of rotation in the planetary gear set, as a result of which the second coupling device 31 is switched from the release position to the coupling position. From this point in time, the second switching state is switched and the planetary gear 24 is in block circulation. The output shaft now has the same speed as the input shaft. A moment path runs as in 5 indicated, from the input shaft section 15 via the planet carrier 27 directly to the output shaft section 16. In particular, the switching unit 14 in the second switching state has a transmission ratio with respect to the speed of i=1.

A major advantage is that no externally actuated actuator is required to switch the switching unit 14, since the actuation is implemented exclusively via centrifugal force. The two-speed switching unit 14 also improves the efficiency of the auxiliary unit 13 with increasing speed, since the switching unit 14 automatically switches to the second switching state from a certain limit speed and adapts the speed of the auxiliary unit 13 accordingly to the speed of the drive motor 2. The ancillary unit 13 can thus be driven at the best possible operating point and the efficiency of the overall system can be increased.

the 6 and 7 each show an alternative embodiment of the switching unit 14, as already shown in FIGS 4 and 5 was described in a schematic representation. 6 shows the switching unit 14 in a first switching state and 7 in a second switching state. According to this embodiment, the sun gear 25 is non-rotatably connected to the input shaft section 15 and the planet carrier 27 is non-rotatably connected to the output shaft section 16 .

As already described above, the first coupling device 30 is arranged between the ring gear 26 and the housing section 32 . The second coupling device 31, on the other hand, is arranged between the input shaft section 15 and the planetary carrier 27, with the second coupling device 31 coupling the planetary carrier 27 to the input shaft section 15 in a torque-proof manner in the coupled position and releasing the input shaft section 15 relative to the planetary carrier 27 in the release position.

In this exemplary embodiment, the first coupling device 30 is designed as the freewheel device in order to automatically switch the first coupling device 30 depending on the direction of rotation, and the second coupling device 31 is designed as the centrifugal device in order to automatically switch the second coupling device 31 depending on the speed.

In the first switching state, the first coupling device 30 is switched to the coupled position and the second coupling device 31 is switched to the release position. Ring gear 26 is blocked in its rotational movement, so that the drive torque introduced via input shaft section 15 is supported in the planetary gear set via housing section 32 and the drive speed is translated into a corresponding output speed at output shaft section 16 . A moment path runs as in 6 indicated, from the input shaft section 15 via the sun gear 25, the planet gears 28 and the planetary carrier 27 to the output shaft section 16. In particular, the switching unit 14 has a transmission ratio in relation to the speed of i>1 in the first switching state.

From a certain limit speed or depending on the centrifugal force, the axial beta compensating force 35 is generated, so that the second coupling device 31 is switched from the release position to the coupling position. This results in a reversal of the direction of rotation in the planetary gear set, as a result of which the first coupling device 30 is switched from the release position to the coupling position. From this point in time, the second switching state is switched and the planetary gear 24 is in block circulation. The output shaft now has the same speed as the input shaft. A moment path runs as in 7 indicated, from the input shaft section 15 via the planet carrier 27 directly to the output shaft section 16. In particular, the switching unit 14 in the second switching state has a transmission ratio with respect to the speed of i=1.

Reference List

1

drive assembly

2

drive motor

3

drive shaft

4

drive wheel section

5

intermediate wheel section

6

intermediate shaft

7

intermediate gear

8th

differential gear

9

output gear section

10

coupling device

11

first output shaft

12

second output shaft

13

ancillary unit

14

switching unit

15

input shaft section

16

output shaft section

17

transmission unit

18

another drive motor

19

another drive shaft

20

further coupling device

21

first partial transmission

22

second sub-transmission

23

output shaft

24

planetary gear

25

sun gear

26

ring gear

27

planet carrier

28

planet gears

29

switching arrangement

30

first coupling device

31

second coupling device

32

housing section

33

operating section

34

braking section

35

operating force

36

first braking partner

37

second braking partner

38

thrust bearing

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• DE 102017128431 A1 [0003]

Claims (10)

Switching unit (14) for coupling an auxiliary unit (13) to a drive train of a motor vehicle, with an input shaft section (15) for the drive connection to the drive train, with an output shaft section (16) for the drive connection to the auxiliary unit (13), with a planetary gear ( 24) for translating a drive speed from the input shaft section (15) to the output shaft section (16), the drive speed in a first switching state of the switching unit (14) in a first transmission ratio and in a second switching state of the switching unit (14) in a second, from the first transmission ratio can be transmitted from the input shaft section (15) via the planetary gear (24) to the output shaft section (16), characterized by a speed-dependent switching arrangement (29), the switching arrangement (29) being designed with the switching unit (14) in dependency of the drive speed between the first switching state and the second switching state to switch automatically. Switching unit (14) after claim 1 , characterized in that the input speed in the first switching state is translated via the planetary gear (24) to the output shaft section (16), so that in the first switching state an output speed at the output shaft section (16) differs from the input speed at the input shaft section (15), and that the input speed in the second switching state is transmitted directly to the output shaft section (16) via the planetary gear (24), so that in the second switching state an output speed at the output shaft section (16) is equal to the input speed at the input shaft section (15). Switching unit (14) after claim 1 or 2 , characterized in that the planetary gear (24) has a sun gear (25), a ring gear (26), a planetary carrier (27) and a plurality of planetary gears (28) and that the switching arrangement (29) has a first coupling device (30) for the non-rotatable coupling of the ring gear (26) with a housing section (32) and a second coupling device (31) for the non-rotatable coupling of the planet carrier (27) to the input shaft section (15) or the output shaft section (16), wherein in the first switching state the ring gear (26) is coupled to the housing section (32) by the first coupling device (30) and the planet carrier (27) is decoupled from the input shaft section (15) or the output shaft section (16) by the second coupling device (31) and wherein in the second switching state the ring gear (26) is decoupled from the housing section (32) by the first coupling device (30) and the planet carrier (27) is connected to the input shaft by the second coupling device 31 Section (15) or the output shaft section (16) is coupled. Switching unit (14) after claim 3 , characterized in that one coupling device (30, 31) is designed as a centrifugal device and the other coupling device (30, 31) as a freewheel device. Switching unit (14) after claim 4 , characterized in that the first coupling device (30) is designed as the centrifugal device and the second coupling device (31) as the freewheel device, wherein in the first switching state the centrifugal device is switched into a coupling position and the freewheeling device is switched into a release position and in the second switching state the centrifugal device is switched to a release position and the freewheel device is switched to a coupled position. Switching unit (14) after claim 4 , characterized in that the first coupling device (30) is designed as the freewheel device and the second coupling device (31) as the centrifugal device, wherein in the first switching state the freewheel device is in a coupling position and the centrifugal device is switched in a release position and and in the second Switching state, the freewheel device is switched into a release position and the centrifugal force device into a coupled position. Switching unit (14) according to one of Claims 4 until 6 , characterized in that the centrifugal device has an actuating section (33) and a braking section (34), the actuating section (34) being designed to transmit an axial actuating force (35) to the braking section (34) as a function of the speed. Switching unit (14) after claim 7 , characterized in that the braking section (34) has a first and a second braking partner (36, 37), the two braking partners (36, 37) being non-rotatably connected to one another in a coupling position and being rotatable relative to one another in a release position. Switching unit (14) after claim 7 or 8th , characterized in that the centrifugal device has an axial bearing (38), the axial bearing (38) being arranged axially between the actuating section (33) and the braking section (34), wherein the actuating force (35) can be transmitted from the actuating section (33) to the braking section (34) via the axial bearing (38). Drive arrangement (1) for a motor vehicle with a drive motor (2) for generating a drive torque, the drive motor (2) being drive-connected to a drive shaft (3) for transmitting the drive torque, the drive shaft (3) for distributing the drive torque to a first and a second output shaft (11, 12) are at least indirectly connected to a differential gear (8), the drive shaft (3) or an intermediate shaft (6) arranged in the power flow between the drive shaft (3) and the differential gear (8) being connected via a Switching unit (14) according to one of Claims 1 until 9 can be connected to an auxiliary unit (13).

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