Electric drive unit and this comprehensive drivetrain system

Abstract

Electric drive unit for use in a drivetrain system (10) comprising a first and a second drivetrain (12, 14) and a primary drive system (20) designed to generate and transmit a first torque to the first drivetrain (12), wherein the second drivetrain (14) comprises a pair of wheels (18) and the electric drive unit comprises the following: an electric motor (32) which serves to selectively generate a second torque; a pinion (34) which is arranged in selective rotary connection with the electric motor (32); a differential (36) arranged in a torque-transmitting relationship between the pinion (34) and the second drive train (14) of the drive train system (10) to distribute a third torque between the pinion (34) and the wheels (18) of the second drive train (14); a first planetary gear set (38) which is arranged in a selective torque-transmitting relationship between the electric motor (32) and the pinion (34); a second planetary gear set (40) arranged in a selective torque-transmitting relationship between the first planetary gear set (38) and the pinion (34); and a jaw coupling arrangement (42) arranged between the pinion (34) and the first and second planetary gear sets (38, 40) in a torque-transmitting relationship, wherein the jaw coupling arrangement (42) is movable between a first position in which the second torque from the electric motor (32) is transmitted through the first planetary gear set (38) and the jaw coupling arrangement (42) to the pinion (34) to drive the wheels (18) of the second drive train (14) with a first predetermined drive ratio, and a second position in which the second torque from the electric motor (32) is transmitted through both planetary gear sets (38, 40) and the jaw coupling arrangement (42) to the pinion (34) to drive the wheels (18) of the second drive train (14) with a second predetermined drive ratio.

Description

BACKGROUND OF THE INVENTION Area of ​​the invention

[0001] The present invention relates to motor vehicle drive systems in general and, in particular, to an electric drive unit for a powertrain system. Description of the state of the art

[0002] Conventional motor vehicles known in the prior art have a powertrain system with one or more drive trains in rotary connection. Typically, the vehicle has a pair of drive trains, each defined by a corresponding pair of opposing wheels. The powertrain system includes a drive system designed to generate torque for propelling the vehicle and to selectively transmit this torque to one or more wheels. For this purpose, in conventional motor vehicle powertrain systems, the drive system is usually implemented as an internal combustion engine in rotary connection with a transmission. The engine generates torque that is selectively transmitted to the transmission, which in turn transmits the torque to one or more of the drive trains.The transmission multiplies the speed and torque generated by the engine through a series of predetermined gear sets, with the ability to switch between gear sets allowing the vehicle to travel at different vehicle speeds for a given engine speed.

[0003] To achieve improved fuel economy and reduced engine emissions, a so-called "hybrid vehicle technology" is increasingly being used in drivetrain systems known from related technologies. In a hybrid vehicle, the drive system typically includes both a gas-powered internal combustion engine and a battery-powered electric motor, both of which work together with the transmission to generate and transmit torque for one or both vehicle drivetrains. Such a hybrid vehicle drive system is designed to optimize the efficiency of the internal combustion engine and / or the electric motor to minimize fuel consumption and engine emissions. Furthermore, the electric motor is often also used as a generator to recharge the battery during vehicle braking, further increasing efficiency and extending the vehicle's range.

[0004] With the advent of improved electric motor and battery technology, state-of-the-art motor vehicles often feature drive systems that can even operate without an internal combustion engine. So-called "electric vehicle" drive systems typically include a large electric motor in rotary connection with a transmission and / or differential, which in turn is used to transmit torque to the wheels of one or both drive trains. Alternatively, in other types of electric vehicle drive systems, each of the vehicle's driven wheels has its own smaller electric motor. Despite the increasing efficiency of state-of-the-art electric drive systems, problems related to limited range and long battery charging times hinder the widespread implementation of electric drive technology in industry.One solution involves equipping the electric vehicle with a "range extender," typically implemented as a small combustion engine that acts solely as an electric generator and is not rotaryally connected to the drive system. However, implementing a range extender is not always feasible in certain applications where vehicle weight, component layout, and zero-emission requirements are critical.

[0005] Each of the components and systems of the type described above must work together to effectively modulate the transmission of torque to the vehicle's driven wheels. Furthermore, each component and system must be designed not only to enable improved performance and efficiency, but also to reduce the cost and complexity of vehicle manufacturing. While powertrain systems known from the prior art have generally demonstrated very good performance, there remains a need in the field for a powertrain system that offers superior operating characteristics, a smaller overall package size, reduced parasitic losses, and increased efficiency, while simultaneously reducing the cost and complexity of vehicle manufacturing.Drive units with corresponding powertrains for electric vehicles and hybrid vehicles are known, for example, from the publications WO 2009 / 021 574 A1, DE 10 2013 222 721 A1, DE 10 2012 220 970 A1 and DE 10 2010 053 855 A1. SUMMARY OF THE INVENTION

[0006] The present invention overcomes the disadvantages of the prior art by providing an electric drive unit for use in a drivetrain system comprising a first and a second drivetrain and a primary drive system for transmitting torque to the first drivetrain. The second drivetrain comprises a pair of wheels. The electric drive unit includes an electric motor for selectively generating torque and a pinion arranged in selective rotary engagement with the electric motor. A differential is arranged in a torque-transmitting relationship between the pinion and the wheels of the second drivetrain system for distributing torque between the pinion and the second drivetrain. A first planetary gear set is arranged in a selective torque-transmitting relationship between the electric motor and the pinion.A second planetary gear set is arranged in a selective torque-transmitting relationship between the first planetary gear set and the pinion. A dog clutch assembly is arranged in a torque-transmitting relationship between the pinion and the planetary gear sets. The dog clutch assembly is movable between a first position, in which torque from the electric motor is transmitted through the first planetary gear set and the dog clutch assembly to the pinion to drive the wheels of the second drive train with a first predetermined drive ratio, and a second position, in which torque from the electric motor is transmitted through both planetary gear sets and the dog clutch assembly to the pinion to drive the wheels of the second drive train with a second predetermined drive ratio.

[0007] Furthermore, the present invention relates to a drivetrain system comprising: a first drivetrain with a first pair of wheels, a second drivetrain with a second pair of wheels, a primary drive system that generates and transmits torque only to the first pair of wheels of the first drivetrain, and an auxiliary drive system that generates and transmits torque only to the second pair of wheels of the second drivetrain. The auxiliary drive system comprises an electric drive unit with an electric motor that selectively generates torque and a pinion gear arranged in selective rotary engagement with the electric motor. A differential is arranged in a torque-transmitting relationship between the pinion gear and the second pair of wheels to distribute the torque between them.A first planetary gear set is arranged in a selective torque-transmitting relationship between the electric motor and the pinion. A second planetary gear set is arranged in a selective torque-transmitting relationship between the first planetary gear set and the pinion. A dog clutch assembly is arranged in a torque-transmitting relationship between the pinion and the planetary gear sets. The dog clutch assembly is movable between a first position, in which torque is transmitted from the electric motor through the first planetary gear set and the dog clutch assembly to the pinion to drive the second pair of wheels with a first predetermined drive ratio, and a second position, in which torque is transmitted from the electric motor through both planetary gear sets and the dog clutch assembly to the pinion to drive the second pair of wheels with a second predetermined drive ratio.

[0008] In this way, the electric drive unit of the present invention significantly improves the performance of vehicle powertrain systems by enabling a simple and space-efficient implementation of battery-powered electric drive systems in vehicles. Furthermore, the present invention offers possibilities for improved vehicle features and enhanced functionality, such as torque vectoring and regenerative braking, while simultaneously providing significant improvements in fuel economy and vehicle range, acceleration, and cornering stability. Moreover, the present invention can be used in conjunction with a variety of different powertrain systems and can be installed or implemented in various ways.Furthermore, the present invention reduces the costs and complexity of manufacturing vehicles that exhibit the best operating characteristics, such as high efficiency, reduced weight and improved emissions, component packaging, component lifespan and vehicle driving behavior. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Further aims, features and advantages of the present invention will become readily apparent when it is better understood after reading the following description in conjunction with the accompanying drawings, in which: Fig. 1 is a schematic top view of a vehicle powertrain system with an electric drive unit according to an embodiment of the present invention. Fig. 2 is a sectional view of the electric drive unit according to an embodiment of the present invention in a high-range configuration. Fig. 3 a sectional view of the electric drive unit of the Fig. 2 in a neutral configuration. Fig. Figure 4 shows a sectional view of the electric drive unit according to an embodiment of the present invention in a low-range configuration. DETAILED DESCRIPTION OF THE INVENTION

[0010] Referring to the figures in which the same reference symbols are used to denote the same structures, at 10 in Fig. Figure 1 shows a schematic representation of a vehicle powertrain system. The powertrain system 10 comprises a first powertrain 12 and a second powertrain 14. In the representative embodiment shown here, the first powertrain 12 comprises a first pair of opposing wheels 16, and the second powertrain 14 comprises a second pair of opposing wheels 18. Those skilled in the art will recognize this as a conventional “four-wheeled” vehicle design, as is commonly used for motor vehicle applications. As will be evident from the following discussion, the vehicle could have any number of powertrains with any suitable number of wheels without thereby departing from the scope of protection of the present invention. The powertrain system 10 further comprises a primary drive system 20 and an auxiliary drive system 22.The primary drive system 20 generates torque for the first pair of wheels 16 of the first drive train 12 and transmits that torque to them. Similarly, and as explained in more detail below, the auxiliary drive system 22 generates torque for the second pair of wheels 18 of the second drive train 14 and transmits that torque to them.

[0011] In the Fig. In the representative example shown in Figure 1, the primary drive system 20 is implemented as a conventional internal combustion engine 24, which is in rotary connection with a transmission 26. The engine 24 generates torque that is selectively transmitted to the transmission 26, which in turn transmits the torque to the first pair of wheels 16. The transmission 26 multiplies the rotational speed and torque generated by the engine 24 and, during operation, transmits the rotation to the wheels 16 to propel the vehicle. For this purpose, the first drive train 12 includes a pair of continuously variable joints 28 (shown schematically) that transmit torque from the transmission 26 to the first pair of wheels 16. Average experts will recognize that the engine 24 and the transmission 26 of the primary drive system 20 are of the type used in conventional "front-transverse drive train" systems 10.Furthermore, it is evident that the motor 24 and / or the gearbox 26 can be of any suitable design and can be configured in any way sufficient to generate torque for the first drive train 12 for transmission and to transfer torque to it, without thereby exceeding the scope of protection of the present invention. It is also evident that the primary drive system 20 could be designed differently or omitted entirely without thereby exceeding the scope of protection of the present invention. As a non-limiting example, the primary drive system 20 could employ a so-called "hybrid motor" in the prior art, wherein torque transmitted to the first drive train 12 is generated by the motor 24 as well as by one or more discrete electric motors (not shown, but generally known in the art).

[0012] As mentioned above, the drivetrain system 10 also includes an auxiliary drive system 22. In the Fig. In the representative example shown in Figure 1, the auxiliary drive system 20 is implemented as an electric drive unit according to the present invention, which is generally characterized by "30". As can be seen from the following description, the electric drive unit 30 can be used in conjunction with any suitable type of vehicle powertrain system 10, with or without the use of a conventional internal combustion engine 24, without thereby exceeding the scope of protection of the present invention. For example, it is conceivable that both the primary drive system 20 and the auxiliary drive system 22 could be implemented as independent electric drive units 30. Likewise, the primary drive system 20 of the powertrain system 10 could be omitted entirely.Although the present invention is designed for use in passenger cars, it is further evident that the electric drive unit 30 could be used in conjunction with any suitable type of vehicle, such as heavy goods vehicles, trains, aircraft, ships, construction vehicles or machines, military vehicles, motorhomes or any other type of vehicle that could benefit from electric torque generation.

[0013] Regarding the Fig. As described in sections 2 to 4, the electric drive unit 30 of the present invention comprises an electric motor 32, a pinion 34, a differential 36, a first planetary gear 38, a second planetary gear 40, and a jaw coupling assembly 42. In the representative embodiment shown here, the electric drive unit 30 further comprises, as explained in more detail below, a main housing 44 which supports, defines, and / or is operatively attached to each of these components.

[0014] The electric motor 32 is in the main housing 44 - for example by one or more bearings, which are generally marked with “46” (see Fig. 2) - supported. The electric motor 32 serves to selectively generate a torque which, as explained in more detail below, is used to drive the second pair of wheels 18 of the second drive train 14. For this purpose, and in one embodiment of the present invention, the auxiliary drive system 22 comprises a battery 48 and a control unit 50, both of which are electrically connected to the electric drive unit 30 (see Fig. 1) The battery 48 is used to power the electric motor 32 during operation and can be of any suitable design, size, or configuration. The control unit 50, sometimes referred to in the prior art as an "electronic control module," is electrically connected to the electric motor 32 and can be configured to modulate, actuate, or otherwise control the claw coupling assembly 42 in order to control the torque transmission between the electric motor 32 and the second pair of wheels 18, as explained in more detail below. Advantageously, the auxiliary drive system 22 can be configured such that the electric motor 32 also functions as a generator, which—for example, through regenerative braking—is used to charge the battery 48. Furthermore, it is also conceivable that the battery 48 is charged while the vehicle is parked using the so-called "plug-in hybrid" technology known from the prior art.

[0015] It is evident that the electric motor 32 could be of any suitable type or configuration sufficient to generate torque using power from the battery 48 without thereby exceeding the scope of protection of the present invention. As a non-limiting example, it is conceivable that the electric motor 32 could be implemented as a DC traction motor or as an AC induction motor. As can be seen from the following description, the specific configuration of the electric motor 32 can be determined based on specific operating requirements of the drive train 10, such as vehicle speed, unladen weight, payload capacity, operating environment, etc.

[0016] As mentioned above, the electric drive unit 30 includes a pinion 34 which is arranged in selective rotary engagement with the electric motor 32. The pinion 34 is mounted in the main housing 44 – for example, by one or more bearings 46 (see figure). Fig. 2) - supported. More precisely, the pinion 34 comprises a compensating bevel gear 52 and a pinion shaft 54. The pinion shaft 54 ​​is coupled to the compensating bevel gear 52, rotates with it, and is arranged in selective rotary engagement with the dog clutch assembly 42. The compensating bevel gear 52 is arranged in tooth mesh with the differential 36 such that it transmits torque between the electric motor 32 and the wheels 18 of the second drive train 14. For this purpose, the differential 36 is arranged in a torque-transmitting relationship between the pinion 34 and the second drive train 14 of the drive train system 10 to distribute the torque between the pinion 34 and the wheels 18 of the second drive train 14. More precisely, the differential 36 comprises a ring 56, a pair of output shafts 58, and a differential assembly generally designated "60". The ring 56 is supported in tooth mesh with the compensating bevel gear 52.In this way, the ring 56 is supported in a rotary connection with the pinion 34. The outputs 58 of the differential 36 are similarly rotatably supported in the differential 36 – for example, by the bearings 46 (see figure). Fig. 2) - and are each arranged in rotary connection with one of the wheels 18 of the second drive train 14. In one embodiment, the electric drive unit 30 comprises an output flange 62 which is operatively connected to each of the output shafts 58 of the differential 36 (see Fig. 1) The output flanges 62 enable a simple connection to the second pair of wheels 18 – for example, by means of a further set of continuously adjustable joints 28. However, those skilled in the art will understand that the electric drive unit 30 could be configured in any way that – with or without the use of the output flanges 62 – is sufficient to transmit a torque from the output shafts 58 to the second pair of wheels 18 of the second drive train 14, without thereby departing from the scope of protection of the present invention.

[0017] The differential assembly 60 is also rotatably supported by the differential 36 - for example by the bearings 46 (see Fig. 2) - and, as mentioned above, is used to distribute torque between the ring 56 and the output shafts 58. Although the differential assembly 60 shown here has a conventional design and uses a bevel gear arrangement (not shown in detail, but generally known in the art) to distribute torque between the wheels 18 of the second drive train 14, it is apparent to those skilled in the art that the differential assembly 60 could be of any suitable type or configuration sufficient to distribute torque between the pinion 34 and the wheels 18 of the second drive train 14 without thereby exceeding the scope of protection of the present invention.As a non-restrictive example, the differential 36 could be designed as a so-called "locking differential" in which "torque-sensitive" gears and / or an arrangement of one or more friction clutch assemblies are used to control the torque distribution between the wheels 18 of the second drive train 14 in a predetermined or selectively adjustable manner (not shown, but generally known in the prior art).

[0018] As mentioned above, the electric drive unit 30 also includes a pair of planetary gear sets 38, 40. The first planetary gear set 38 is arranged in a selective torque-transmitting relationship between the electric motor 32 and the pinion 34. Similarly, the second planetary gear set 40 is arranged in a selective torque-transmitting relationship between the first planetary gear set 38 and the pinion 34. Furthermore, the jaw coupling assembly 42 is arranged in a torque-transmitting relationship between the pinion 34 and the planetary gear sets 38, 40. The jaw coupling assembly 42 is selectively movable between a first position 42A (see Figure 1). Fig. 2) and a second position 42B (see Fig. 4) In one embodiment, the claw coupling arrangement 42 is also selectively movable into a third position 42C, as explained in more detail below (see Fig. 3) When the claw coupling arrangement 42 is in the first position 42A (see Fig. 2), a torque from the electric motor 32 is transmitted through the first planetary gear set 38 and the dog clutch assembly 42 to the pinion 34 to drive the wheels 18 of the second drive train 14, as explained in more detail below, with a first predetermined drive ratio DR1. If, on the other hand, the dog clutch assembly 42 is in the second position 42B (see Fig. 4), a torque is transmitted from the electric motor 32 through both planetary gear sets 38, 40 and additionally through the claw coupling arrangement 42 to the pinion 34 in order to drive the wheels 18 of the second drive train 14, as explained in more detail below, with a second predetermined drive ratio DR2.

[0019] The first planetary gear set 38 comprises a first sun gear 64, a plurality of first planet gears 66 arranged in meshing relation with the first sun gear 64, and a first carrier 68 that supports the first planet gears 66. The first carrier 68 rotates in the same direction as the pinion 34 when the jaw coupling assembly 42 is in the first position 42A (see Fig. 2) In one embodiment, the electric motor 32 comprises a motor output shaft, generally designated “70”, which is operatively connected to the first sun gear 64 of the first planetary gear set 38 – for example, by a positive fit between them (not shown in detail, but generally known in the prior art). Therefore, the output shaft 70 of the electric motor 32 is coupled to the first sun gear 64 of the first planetary gear set 38 and rotates in the same direction as it. However, those skilled in the art will recognize that the first sun gear 64 could be operatively connected to the electric motor 32 in any way without thereby exceeding the scope of protection of the present invention.Furthermore, it is evident that the first planetary gear 38 could be configured in different ways sufficient to selectively transmit a torque between the electric motor 32 and the pinion 34, as mentioned above, without thereby departing from the scope of protection of the present invention.

[0020] In one embodiment, the second planetary gear 40 comprises a second sun gear 72, a plurality of second planet gears 74 arranged in meshing relation with the second sun gear 72, and a second support 76 that supports the second planet gears 74. The second support 76 rotates in sync with the pinion 34 when the jaw coupling assembly 42 is in the second position 42B (see Fig. 4) It is evident that the second planetary gear 40 could be configured in different ways sufficient to selectively transmit a torque between the first planetary gear 38 and the pinion 34, as mentioned above, without thereby departing from the scope of protection of the present invention.

[0021] In the Fig. In the representative embodiment of the electric drive unit 30 shown in Figures 2 to 4, the second sun gear 72 of the second planetary gear 40 is formed integrally with the first carrier 68 of the first planetary gear 38. It is evident that this configuration advantageously optimizes the overall packaging size of the electric drive unit 30 and contributes to simplified component assembly during manufacturing. Similarly, in one embodiment, the first planetary gear 38 and the second planetary gear 40 are both supported in tooth mesh with a common ring gear 78, which in turn is supported in the main housing 44, further simplifying the assembly of the electric drive unit 30.However, those skilled in the art will recognize that the planetary gears 38, 40 could be arranged or otherwise configured in any way sufficient to interact with the jaw coupling arrangement 42 in order to effect a selective transmission of torque between the electric motor 32 and the pinion 34, as mentioned above, without thereby departing from the scope of protection of the present invention.

[0022] It is evident that the planetary gear sets 38, 40 and the differential 36 can each be configured to adjust the rotational speed and / or the torque generated by the electric motor 32 in such a way as to transmit torque to the wheels 18 of the second drive train 14 in such a manner that, under certain predetermined vehicle operating conditions, particularly advantageous operating conditions of the electric motor 32 can be utilized, thereby optimizing the efficiency of the entire drive train system 10. More precisely, the ring 56 of the differential 36 and the compensating bevel gear 52 of the pinion 34 define a differential reduction ratio GRD, the first sun gear 64 and the first planet gears 66 of the first planetary gear set 38 define a first reduction ratio GR1, and the second sun gear 72 and the second planet gears 74 of the second planetary gear set 40 define a second reduction ratio GR2.The first drive ratio DR1 is equal to the product of the differential reduction ratio GRD and the first reduction ratio GR1. In other words, DR1 = GRD * GR1. Similarly, the second drive ratio DR2 is equal to the product of the differential reduction ratio GRD, the first reduction ratio GR1, and the second reduction ratio GR2. In other words, DR2 = GRD * GR1 * GR2. Therefore, these ratios can be adjusted depending on the application of the drivetrain 10, allowing different ratios to be implemented for vehicles with varying requirements regarding weight, top speed, acceleration, and the like.The inventors have found that a first reduction ratio GR1 of between 2.6:1 and 5.0:1, a second reduction ratio GR2 of between 2.6:1 and 5.0:1, and a differential reduction ratio of between 2.5:1 and 4.0:1 are particularly advantageous for powertrain systems 10 implemented in connection with passenger car powertrain systems 10, such that a significant compromise is achieved between overall component size and packaging complexity, vehicle speed and payload capacity, and efficient use of the engine operating range. In one embodiment, the first reduction ratio GR1 is equal to the second reduction ratio GR2. In other words, GR1 = GR2.

[0023] It is understood that the configuration of the drive ratios DR1, DR2 described above optionally allows the electric drive unit 30 to operate in a so-called "high range" when the claw coupling arrangement 42 is in the first position 42A (see Fig. 2), and in a “low range” when the claw coupling arrangement 42 is in the second position 42B (see Fig. 4), effect. As mentioned above, in one embodiment the claw coupling arrangement 42 can optionally also be moved into a third position 42c, in which a torque between the electric motor 32 and the pinion 34 is interrupted (see Fig. 3) Average experts will recognize that an interruption between the electric motor 32 and the pinion 34 defines a so-called “neutral” or “freewheel” configuration, which is advantageously implemented in certain types of drivetrain systems 10, such as those in which a DC traction motor arrangement is used as the electric motor 32, wherein the third position 42C can be used to increase the efficiency of the second drivetrain 14 by reducing an electromotive force (sometimes referred to in the prior art as “back EMF”) at relatively high vehicle speeds or during other predetermined vehicle operating conditions.However, average experts will recognize that, depending on the specific requirements of the drive train system 10, the claw coupling arrangement 42 could be implemented without a separate third position 42C without thereby departing from the scope of protection of the present invention.

[0024] To effect the movement of the jaw coupling assembly 42 between positions 42A, 42B and 42C, the electric drive unit 30 can include an actuator, generally designated “80”. As shown in the Fig. As shown in Figures 2 to 4, the actuator 80 is supported within the main housing 44 and is used to move a slide 82, which in turn moves the jaw coupling assembly 42 between positions 42A, 42B, and 42C. In the representative embodiment shown in all figures, the actuator 80 is implemented as a plunger, which is actuated, for example, by pressurized hydraulic fluid (not shown in detail, but generally known in the prior art). However, those skilled in the art will recognize that the actuator 80 could be of any suitable type or configuration sufficient to move the jaw coupling assembly 42 between positions 42A, 42B, and 42C without thereby exceeding the scope of the present invention. As a non-limiting example, the actuator 80 could be an electric linear actuator driven by the controller 50 (see Figure 2 to 4). Fig. 1; not shown in detail, but generally known in the prior art).

[0025] As mentioned above, selective actuation of the actuator 80 pushes the slide 82, which in turn moves the jaw coupling assembly 42 between positions 42A, 42B, and 42C. For this purpose, the jaw coupling assembly 42, in one embodiment, comprises an interface coupling 84, a first engagement coupling 86, a second engagement coupling 88, and a ring assembly 90. The interface coupling 84 is operatively mounted on the pinion shaft 54 ​​and rotates in sync with it. The ring assembly 90 is operatively mounted on the slide 82 and moves in sync with it (compare the Fig. 2 to 4). The first engagement coupling 86 is operatively connected to the first carrier 68 of the first planetary gear 38 and rotates in sync with it. Similarly, the second engagement coupling 88 is operatively connected to the second carrier 76 of the second planetary gear 40 and rotates in sync with it. The ring assembly 90 has internal teeth, generally designated 90A, and the couplings 84, 86, and 88 each have external teeth, generally designated 84A, 86A, and 88A, respectively. The internal teeth 90A of the ring assembly 90 mesh with and move along the external teeth 84A of the interface coupling 84 when the slide 82 moves between positions 42A, 42B, and 42C.When the slide 82 moves the jaw coupling arrangement 42 into the first position 42A, the internal teeth 90A of the ring 90 engage simultaneously with the external teeth 84A of the interface coupling 84 and with the external teeth 86A of the first engagement coupling 86 (see . Fig. 2) When the slide 82 moves the jaw coupling assembly 42 into the second position 42B, the internal teeth 90A of the ring 90 engage simultaneously with the external teeth 84A of the interface coupling 84 and with the external teeth 88A of the second engagement coupling 88 (see Fig. 4) Furthermore, when the slide 82 moves the jaw coupling assembly 42 into the third position 42C, the internal toothing 90A of the ring 90 engages with the external toothing 84A of the interface coupling 84 and is connected to both the external toothing 86A of the first engagement coupling 86 and the external toothing 88A of the second engagement coupling 88 (see Fig.3) spaced apart. Those skilled in the art will recognize that the jaw coupling arrangement 42 described here transmits a torque between the pinion 34 and the planetary gears 38, 42 via interference engagement of the gear teeth 84A, 86A, 88A, 90A. This design significantly avoids parasitic friction losses during operation and contributes to increased efficiency of the electric drive unit 30. Furthermore, it is evident that the jaw coupling arrangement 42 – using any suitable arrangement or combination of components sufficient to effect selective torque transmission between the pinion 34 and the planetary gears 38, 42 via interference engagement – ​​could be supported, configured, or otherwise oriented in different ways without thereby exceeding the scope of protection of the present invention.In one embodiment, each of the engagement couplings 86, 88 comprises a synchronizing device, generally characterized by “92”, to enable smooth engagement with the ring 90 when the slide 82 moves the claw coupling arrangement 42 between positions 42A, 42B and 42C (not shown in detail, but generally known in the prior art).

[0026] In this way, the electric drive unit 30 and the drivetrain system 10 of the present invention significantly improve the performance of vehicles by enabling a simple and space-efficient implementation of battery-powered electric auxiliary drive systems 22. In particular, it is evident that the present invention allows vehicles to benefit from advantages traditionally reserved for hybrid or electric vehicles, such as regenerative braking and rapid torque availability across a wide range of vehicle operating speeds.In this way, an otherwise conventional front-wheel-drive vehicle with an internal combustion engine 24 can be easily and cost-effectively equipped with the electric drive unit 30 according to the present invention, while simultaneously providing significant improvements in fuel economy / vehicle range, acceleration, traction, and all-wheel-drive functionality. Furthermore, the electric drive unit 30 and the powertrain system 10 of the present invention reduce the cost and complexity of manufacturing vehicles that exhibit superior operating characteristics, such as high efficiency, reduced weight and improved emissions, component packaging, component lifespan, and vehicle handling.

[0027] The invention has been described in an illustrative manner. It is understood that the terminology used is descriptive and not limiting. In light of the foregoing, numerous variations and modifications of the invention are possible. Therefore, within the scope of protection of the attached claims, the invention can be implemented in practice in ways other than those described here.

Claims

[1] Electric drive unit for use in a drivetrain system (10) comprising a first and a second drivetrain (12, 14) and a primary drive system (20) designed to generate and transmit a first torque to the first drivetrain (12), wherein the second drivetrain (14) comprises a pair of wheels (18) and the electric drive unit comprises: an electric motor (32) which serves to selectively generate a second torque; a pinion (34) which is arranged in selective rotary connection with the electric motor (32); a differential (36) arranged in a torque-transmitting relationship between the pinion (34) and the second drive train (14) of the drive train system (10) to distribute a third torque between the pinion (34) and the wheels (18) of the second drive train (14); a first planetary gear set (38) which is arranged in a selective torque-transmitting relationship between the electric motor (32) and the pinion (34); a second planetary gear set (40) arranged in a selective torque-transmitting relationship between the first planetary gear set (38) and the pinion (34); and a jaw coupling arrangement (42) arranged between the pinion (34) and the first and second planetary gear sets (38, 40) in a torque-transmitting relationship, wherein the jaw coupling arrangement (42) is movable between a first position in which the second torque from the electric motor (32) is transmitted through the first planetary gear set (38) and the jaw coupling arrangement (42) to the pinion (34) to drive the wheels (18) of the second drive train (14) with a first predetermined drive ratio, and a second position in which the second torque from the electric motor (32) is transmitted through both planetary gear sets (38, 40) and the jaw coupling arrangement (42) to the pinion (34) to drive the wheels (18) of the second drive train (14) with a second predetermined drive ratio. [2] Electric drive unit according to claim 1, further comprising a common ring gear (78) which supports the first planetary gear (38) and the second planetary gear (40). [3] Electric drive unit according to claim 1, wherein the first planetary gear (38) comprises a first sun gear (64), a plurality of first planet gears (66) arranged in meshing relation with the first sun gear (64), and a first support (68) supporting the first planet gears (66); and wherein the first support (68) rotates in sync with the pinion (34) when the jaw coupling arrangement (42) is in the first position. [4] Electric drive unit according to claim 3, wherein the first sun wheel (64) is operatively attached to the electric motor (32). [5] Electric drive unit according to claim 3, wherein the second planetary gear (40) comprises a second sun gear (72), a plurality of second planet gears (74) arranged in meshing relation with the second sun gear (72), and a second carrier (76) supporting the second planet gears (74); and wherein the second carrier (76) rotates in sync with the pinion (34) when the jaw coupling arrangement (42) is in the second position. [6] Electric drive unit according to claim 5, wherein the first carrier (68) of the first planetary gear (38) is formed integrally with the second sun gear (72) of the second planetary gear (40). [7] Electric drive unit according to claim 1, wherein the claw coupling arrangement (42) is selectively movable into a third position in which the torque between the electric motor (32) and the pinion (34) is interrupted. [8] Electric drive unit according to claim 1, further comprising an actuator (80) for selectively moving the claw coupling arrangement (42) between the first and second positions. [9] Electric drive unit according to claim 1, wherein a ring (56) of the differential (36) is supported in rotary connection with the pinion (34). [10] Electric drive unit according to claim 9, wherein the ring (56) and the pinion (34) form a differential reduction ratio, wherein the first planetary gear (38) defines a first reduction ratio and the second planetary gear (40) defines a second reduction ratio; and wherein the first predetermined drive ratio is equal to the product of the differential reduction ratio and the first reduction ratio; and the second predetermined drive ratio is equal to the product of the differential reduction ratio, the first reduction ratio and the second reduction ratio. [11] Electric drive unit according to claim 10, wherein the first reduction ratio is equal to the second reduction ratio. [12] Powertrain system, comprising: a first drive train (12) with a first pair of wheels (16); a second drive train (14) with a second pair of wheels (18); a primary drive system (20) that functions to generate and transmit a first torque only to the first pair of wheels (16) of the first drive train (12); an additional drive system (22) that functions to generate and transmit a second torque only for the second pair of wheels (18) of the second drive train (14), wherein the additional drive system (22) comprises an electric drive unit (30) having the following features: an electric motor (32) which serves to selectively generate a third torque; a pinion (34) which is arranged in selective rotary connection with the electric motor (32); a differential (36) arranged in a torque-transmitting relationship between the pinion (34) and the second pair of wheels (18) to distribute a fourth torque between the pinion (34) and the second pair of wheels (18); a first planetary gear set (38) which is arranged in a selective torque-transmitting relationship between the electric motor (32) and the pinion (34); a second planetary gear set (40) arranged in a selective torque-transmitting relationship between the first planetary gear set (38) and the pinion (34); and a jaw coupling arrangement (42) arranged between the pinion (34) and the first and second planetary gear sets (38, 40) in a torque-transmitting relationship, wherein the jaw coupling arrangement (42) is movable between a first position in which the third torque from the electric motor (32) is transmitted through the first planetary gear set (38) and the jaw coupling arrangement (42) to the pinion (34) to drive the second pair of wheels (18) with a first predetermined drive ratio, and a second position in which the third torque from the electric motor (32) is transmitted through both planetary gear sets (38, 40) and the jaw coupling arrangement (42) to the pinion (34) to drive the second pair of wheels (18) with a second predetermined drive ratio. [13] Powertrain system according to claim 12, wherein the auxiliary drive system (22) comprises a battery (48) which is electrically connected to the electric motor (32) of the electric drive unit (30). [14] Powertrain system according to claim 12, wherein the primary drive system (20) comprises an internal combustion engine (24). [15] Drive train system according to claim 12, wherein the primary drive system (20) is further configured as a further electric drive unit.

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