Torque transmission device for vehicle

Abstract

The invention relates to a torque transmission device for a vehicle, in particular to a torque transmission device for distributing torque from an input shaft (2) to a first and a second output shaft (3; the invention relates to a torque transmitting device (1) comprising a planetary gear system (10, 410, 510, 610) and a first shifting device (20) selectively settable to one of a first position, a second position, and a third position, in which:-in the first position, the planetary gear system (10, 410, 510, 610) is driven by the planetary gear system (10, 410, 510, 610); the torque transmitting device provides increased output torque to the first output shaft and the second output shaft via a planetary gear system; -in the second position, the torque transmitting device provides only an increased output torque to the first output shaft; and-in the third position, the torque transmitting device provides output torque only to the first output shaft at a direct gear ratio or at a gear ratio lower than the second position.

Description

TECHNICAL FIELD

[0001] The present disclosure relates generally to powertrains for vehicles. In particular aspects, the present disclosure relates to a torque transfer device, a powertrain and a vehicle. The present disclosure can be applicable to heavy-duty vehicles, such as trucks, buses and construction equipment and other vehicle types. Although the present disclosure can be described in relation to a particular vehicle, the present disclosure is not limited to any particular vehicle. BACKGROUND

[0002] In vehicles having two or more drive axles, a torque transfer device (also referred to as transfer case and sometimes also as differential) can be used in addition to the main transmission to transfer torque from the prime mover to the drive axles. The main transmission converts the torque and rotational speed of the prime mover to provide different gear ratios, while the torque transfer device is mainly used to distribute the torque of the main transmission between the axles. It can be asymmetric, i.e. distribute the torque unequally between the axles, or symmetric, i.e. distribute the torque equally. A differential can also be provided at each axle, via which torque is supplied to the drive wheels of the vehicle. SUMMARY

[0003] According to a first aspect of the present invention, there is provided a torque transfer device configured to distribute torque from an input shaft to a first output shaft and a second output shaft configured to drive a first axle and a second axle of a vehicle, respectively. The torque transfer device comprises a planetary gear system comprising a sun gear, a ring gear and a planet carrier carrying a plurality of planet gears, and a first shift device selectively settable to one of a first position, a second position and a third position, wherein:

[0004] - in the first position, the torque transfer device is configured to provide an output torque to the first output shaft and the second output shaft via the planetary gear system, the output torque to each of the output shafts being greater than an input torque provided via the input shaft,

[0005] - in the second position, the torque transfer device is configured to provide an output torque to the first output shaft only, the output torque being greater than the input torque, and

[0006] - in the third position, the torque transfer device is configured to provide an output torque to the first output shaft only, at a direct drive ratio or at a lower drive ratio than in the second position.

[0007] A first aspect of the present disclosure can seek to provide an at least in some respects improved torque transfer device for distributing torque between axles of a vehicle having two or more axles. In particular, the present invention aims to provide a torque transfer device that is capable of providing different drive modes, thereby enabling different torque distribution between the axles. Technical benefits can include providing a torque transfer device that is capable of switching between a four-wheel drive mode providing startability and increased traction in muddy conditions and at least two different two-wheel drive modes respectively suited for starting and cruising. In addition to being capable of switching between four-wheel drive and two-wheel drive, the torque transfer device can also replace a conventional range gear of a transmission, as it provides the functionality of a low range gear in the second position and a high range gear in the third position. A compact torque transfer device can thereby be achieved, while providing the possibility of torque increase and switching between two-wheel drive and four-wheel drive.

[0008] Optionally, in some examples, including in at least one preferred example, the input shaft is drivingly connected to the first output shaft via a first gear and a second gear of the planetary gear system. Thus, the first gear forms an input gear and the second gear forms an output gear. Technical benefits can include a permanent driving connection between the input shaft and the first output shaft.

[0009] Optionally, in some examples, including in at least one preferred example, in the first position, the first shift device is configured to lock the second output shaft for co-rotation with a third gear of the planetary gear system. Technical benefits can include selective torque transfer to the second output shaft via the first shift device to provide a four-wheel drive mode suited for high transmission ratios.

[0010] Optionally, in some examples, including in at least one preferred example, in the second position, the first shift device is configured to lock the third gear to a fixed member of the torque transfer device, such as to a housing, and to drivingly disconnect the second output shaft from the third gear. Technical benefits can include selectively disconnecting the second output shaft from the input shaft to provide a two-wheel drive mode.

[0011] Optionally, in some examples, including in at least one preferred example, in the third position, the first shift device is configured to lock the third gear for co-rotation with the first gear and / or the input shaft, and to drivingly disconnect the second output shaft from the third gear. Technical benefits can include directly transferring torque in cruising conditions, while reducing frictional losses of the first output shaft.

[0012] Optionally, in some examples, including in at least one preferred example, the input shaft is fixed for co-rotation with the sun gear, or the input shaft is configured to be fixed for co-rotation with the sun gear via a second shift device. Technical benefits can include that a torque multiplication can thereby be achieved by the planetary gear system. An alternative is to fix the input shaft for co-rotation with the ring gear, but in this way a smaller step in gear ratio between the various positions of the first shift device is achieved. It is generally not preferred to fix the input shaft for co-rotation with the planet carrier, since the transmission ratios provided in this configuration are less useful.

[0013] Optionally, in some examples, including in at least one preferred example, the first output shaft is fixed for co-rotation with the planet carrier, and the second output shaft is selectively connectable to the ring gear via the first shift device. Technical benefits can include that in all three positions of the first shift device, the first output shaft will thus rotate in the same direction as the input shaft. This is very advantageous for a powertrain in which the input shaft is always rotated in the same direction, such as when the prime mover is an internal combustion engine.

[0014] Optionally, in some examples, including in at least one preferred example, the first shift device is configured to selectively lock the ring gear to a fixed member of the torque transfer device, such as a housing.

[0015] Optionally, in some examples, including in at least one preferred example, the first output shaft is fixed for co-rotation with the ring gear, and the second output shaft is selectively connectable to the planet carrier via the first shift device. This configuration is mainly useful when the prime mover is an electric machine that can be rotated in both directions, since the first output shaft and the input shaft will then rotate in opposite directions.

[0016] Optionally, in some examples, including in at least one preferred example, the input shaft, as well as the first output shaft and the second output shaft, are arranged coaxially. At least one of the shafts can be a hollow shaft.

[0017] Optionally, in some examples, including in at least one preferred example, the input shaft is a hollow shaft configured to receive the first output shaft. Technical benefits can include that a compact powertrain can be achieved.

[0018] Optionally, in some examples, including in at least one preferred example, the second output shaft is a hollow shaft configured to receive one of the input shaft and the first output shaft. When the second output shaft is a hollow shaft configured to receive the first output shaft, a simplified assembly can be achieved, in particular when the torque transfer device is used to distribute torque between two axles arranged on the same side of the prime mover, i.e. either the rear side or the front side thereof.

[0019] Optionally, in some examples, including in at least one preferred example, the first output shaft is a hollow shaft configured to receive the input shaft. This can be useful if it is desired that there is an offset between the input shaft and the driven shaft of the vehicle, as an external gear can be provided on the first output shaft, which in turn can be used to drive the driven shaft.

[0020] Optionally, in some examples, including in at least one preferred example, the torque transfer device further comprises a second shift device, the first shift device and the second shift device being configured to selectively switch the input gear for torque transfer via the torque transfer device. A technical benefit can include the possibility to achieve additional gear ratios for torque transfer via the first output shaft. Preferably, the second shift device can be used together with the first shift device to switch the input gear, such that depending on the positions of the first shift device and the second shift device, either the sun gear or the ring gear can be used as the input gear.

[0021] Optionally, in some examples, including in at least one preferred example, the second shift device is selectively settable in one of a locked position, in which the second shift device locks the first gear of the planetary gear system to a fixed member of the torque transfer device, such as to the housing, and an unlocked position, in which the second shift device unlocks the first gear from the fixed member and locks it for co-rotation with the input shaft.

[0022] Optionally, in some examples, including in at least one preferred example, the first gear is the sun gear. A technical benefit can include that a torque increase can thereby be achieved by the planetary gear system.

[0023] Optionally, in some examples, including in at least one preferred example, the torque transfer device is configured to provide four drive modes, including:

[0024] - a four-wheel drive mode, in which the first shift device is in the first position and the second shift device is in the unlocked position,

[0025] - a low-speed gear drive mode, in which the first shift device is in the second position and the second shift device is in the unlocked position,

[0026] - an underdrive mode, in which the first shift device is in the third position and the second shift device is in the locked position, and

[0027] - direct drive mode, wherein the first shift device is in the third position and the second shift device is in the unlocked position,

[0028] Technical benefits can include greater available gear ratio selection, and thereby improved versatility of the torque transfer device.

[0029] Optionally, in some examples, including in at least a preferred example, at least the first shift device comprises a sleeve configured to be actuated by an actuation device, such as a shift fork. The second shift device can also comprise a sleeve configured to be actuated by an actuation device, such as a shift fork.

[0030] According to a second aspect of the present disclosure, there is provided a powertrain for a vehicle. It comprises a torque transfer device of the first aspect, at least one prime mover, and a first axle and a second axle, wherein the input shaft is drivingly connected to the at least one prime mover, and wherein the first output shaft and the second output shaft are arranged for driving the first axle and the second axle, respectively.

[0031] The second aspect of the present disclosure can seek to provide a powertrain for a vehicle, such as a heavy vehicle, with at least some improved aspects. In particular, it can seek to provide a powertrain with different drive modes and different torque distribution between axles. Technical benefits can include providing a torque transfer device that can be arranged in a four-wheel drive mode providing startability and increased traction in muddy conditions, or in one of at least two different two-wheel drive modes, each being suitable for start and cruise, respectively.

[0032] According to a third aspect of the present disclosure, there is provided a vehicle comprising a powertrain of the second aspect. The vehicle can be a heavy vehicle, such as a bus, a truck or a working machine. In some examples, the vehicle can be a combination vehicle comprising a tractor vehicle and a trailer, wherein one of the first axle and the second axle is arranged in the tractor vehicle and the other of the first axle and the second axle is arranged in the trailer.

[0033] Those of ordinary skill in the art will appreciate that the disclosed aspects, examples, including any preferred examples, and / or the accompanying claims can be suitably combined. Additional features and advantages will be disclosed in the following description, the claims, and the appended drawings, and will become apparent to those skilled in the art. BRIEF DESCRIPTION OF DRAWINGS

[0034] Examples are described in more detail below with reference to the accompanying drawings. The drawings are schematic and not drawn to scale.

[0035] Figure 1This is an example vehicle based on the example.

[0036] Figure 2 This is an exemplary powertrain system based on the example.

[0037] Figures 3a to 3c A torque transmission device according to the first example is shown.

[0038] Figures 4a to 4c A torque transmission device according to the second example is shown.

[0039] Figure 5 A torque transmission device according to the third example is shown.

[0040] Figures 6a to 6d A torque transmission device according to the fourth example is shown.

[0041] Figures 7a to 7c A torque transmission device based on other examples is shown.

[0042] Figure 8 This is an exemplary powertrain system based on another example. Detailed Implementation

[0043] The detailed description set forth below provides information and examples of the disclosed technology in sufficient detail to enable those skilled in the art to practice this disclosure.

[0044] Vehicles with a powertrain system featuring two or more drive axles may include, in addition to a transmission that changes the torque and speed of the prime mover to provide different gear ratios, a torque transmission device, also known as a transfer case, that distributes torque between the drive axles. A differential gear is also provided on each drive axle, which distributes torque from the transfer case to each of the drive wheels, allowing the drive wheels to rotate at different speeds in corners. The transfer case's distribution of torque from the transmission between the axles can be asymmetrical, i.e., unequally distributed torque between the axles, or symmetrical, i.e., equally distributed torque between the axles. In some vehicles, switching between four-wheel drive and two-wheel drive is possible, with four-wheel drive used to provide maximum traction in, for example, muddy conditions, while two-wheel drive is used during "normal" conditions.

[0045] In heavy-duty vehicles, transmissions typically allow switching between high and low gears to expand the speed range available to the transmission's primary gear set. This functionality can be achieved, for example, through a planetary gear system coupled with the primary gear set. While maximum traction is generally only required at high torque levels, i.e., in low gears, rather than during normal cruising at high speeds, torque distribution and torque conversion are usually separate functions using different hardware. This disclosure seeks to combine the functionality of torque distribution and range gear selection.

[0046] Figure 1 An exemplary vehicle 100 in the form of a towing truck is shown according to an example. It includes a first axle 101, here a front axle, which includes a first wheel 110. It also includes a second axle 102, here a rear axle, which includes a second wheel 120. Vehicle 100 may be an electric vehicle, a hybrid vehicle, or a vehicle powered by an internal combustion engine.

[0047] Figure 2 The vehicle (such as) is shown schematically. Figure 1 The powertrain 110 of the vehicle 100 shown includes a first axle 101 and a second axle 102. The powertrain 110 also includes a prime mover 103 in the form of an electric motor, configured to provide propulsive power for driving the vehicle 100. The prime mover 103 is driven to the axles 101 and 102 via a torque transmission device 1. An input shaft 2 transmits the input torque generated by the prime mover 103 to the torque transmission device 1, and the torque is further transmitted via a first output shaft 3 to the first axle 101 (such as a front axle) and via a second output shaft 4 to the second axle 102 (such as a rear axle). In other examples, the first axle 101 may be a rear axle, and the second axle 102 may be a front axle. In some cases, a gearbox (not shown) may be provided in addition to the torque transmission device 1; however, in this example, when an electric motor is used as the prime mover 103, the gearbox can be omitted.

[0048] Figures 3a to 3c Showing more details Figure 2 The torque transmission device 1 shown is in three different driving modes, including a four-wheel drive mode with good traction and good startability suitable for muddy conditions. Figure 3a ), low-speed two-wheel drive mode ( Figure 3b ) and high-speed gear or direct two-wheel drive mode ( Figure 3c The torque transmission device 1 includes a planetary gear system 10 configured to connect an input shaft 2 to a first output shaft 3 and a second output shaft 4. The planetary gear system 10 includes a central gear 11, a ring gear 13, and a planetary gear carrier 12 carrying a plurality of planetary gears 14. A first shifting device 20 is also provided, which can be selectively configured to one of a first position, a second position, and a third position. In the example shown in FIG3, the input shaft 2 is permanently driven to the central gear 11, the first output shaft 3 is permanently driven to the planetary gear carrier 12, and the second output shaft 4 is selectively driven to the ring gear 13. In the example shown, the input shaft 2 is a hollow shaft, and the first output shaft 3 is rotatably received within the hollow shaft.

[0049] like Figure 3aAs shown, in the first position of the first shifting device 20, the torque transmission device 1 is configured to provide output torque to both the first output shaft 3 and the second output shaft 4 via the planetary gear system 10. The output torque to each of the output shafts 3 and 4 is greater than the input torque provided via the input shaft 2. "Greater than" means that the magnitude of the output torque is greater than the magnitude of the input torque. Figure 3a As shown, the first output shaft 3 rotates in the same direction as the input shaft 2, while the second output shaft 4 rotates in the opposite direction, thus the output torques are in opposite directions. The relative magnitudes of the rotation directions and torques are indicated by curved arrows.

[0050] In such Figures 3a to 3c When the torque transmission device 1 shown is in the first position, the first shifting device 20 drives the ring gear 13 to the second output shaft 4, that is, it locks the ring gear 13 to rotate together with the second output shaft 4. Torque is transmitted from the input shaft 3 to the first output shaft 3 via the center gear 11, planetary gear 14 and planetary gear carrier 12, and from the input shaft 3 to the second output shaft 4 via the center gear 11, planetary gear carrier 14 and ring gear 13.

[0051] In the second position of the first shifting device 20, such as Figure 3b As shown, the torque transmission device 1 is configured to provide output torque only to the first output shaft 3, and the output torque is greater than the input torque. To achieve this, the first shifting device 20 locks the ring gear 13 to the fixing member 30 of the torque transmission device (such as locking it to the housing) and drives the second output shaft 4 away from the ring gear 13. In this way, torque is transmitted from the input shaft 2 to the first output shaft 3 via the central gear 11, planetary gear 14, and planetary gear carrier 12 at the same gear ratio as the first position of the first shifting device 20. The direction of the output torque is the same as the direction of the input torque.

[0052] In the third position of the first shifting device 20, the torque transmission device 1 is configured to provide output torque only to the first output shaft 3 at a direct drive ratio. To achieve this, the first shifting device 20 locks the ring gear 13 to rotate together with the center gear 11 and drives the second output shaft 4 away from the ring gear 13. Thus, torque is transmitted from the input shaft 2 to the first output shaft 3 via the locked planetary gear system 10. The direction of the output torque is the same as the direction of the input torque.

[0053] Figures 4a to 4c Another example of a torque transmission device 401 for vehicle 100 is shown, which is in relation to... Figures 3a to 3cThe illustrated driving mode corresponds to a third different driving mode. The torque transfer device 401 comprises a planetary gear system 410 configured to connect the input shaft 402 to the first output shaft 403 and to the second output shaft 404. The planetary gear system 410 comprises a sun gear 411, a ring gear 413 and a planet carrier 412 carrying a plurality of planet gears 414. Further, a first shift device 420 is provided, which can be selectively set into one of a first position, a second position and a third position.

[0054] Figures 4a to 4c The illustrated torque transfer device 401 differs from the torque transfer device 401 illustrated in Figures 3a to 3c by the fact that the first output shaft 403 is permanently drivingly connected to the ring gear 413 and by the fact that the second output shaft 404 is selectively drivingly connectable to the planet carrier 412 via the first shift device 420.

[0055] In the Figure 4a , the first shift device 420 is set into the first position, i.e. a four-wheel drive mode is achieved, wherein an increased output torque is supplied to both axles 101, 102 of the vehicle 100. To this end, the first shift device 420 fixes the planet carrier 412 to be co-rotating with the second output shaft 404. Thus, the second output torque supplied to the second output shaft 404 will have the same direction as the input torque, whereas the first output torque supplied to the first output shaft 403 will have the opposite direction as the input torque.

[0056] In the Figure 4b , the first shift device 420 fixes the planet carrier 412 to a stationary member 430 such that the planet carrier 412 is prevented from rotating. It further drivingly disconnects the second output shaft 404 from the planet carrier 412. Torque is only supplied to the first output shaft 403, wherein the output torque is higher than the input torque and has the opposite direction of the torque.

[0057] In the Figure 4c , the first shift device 420 locks the sun gear 411 to be co-rotating with the planet carrier 412. It further drivingly disconnects the second output shaft 404 from the planet carrier 412. Thereby, torque is transferred from the input shaft 402 to the first output shaft 403 via the locked planetary gear system 410. The direction of the output torque is the same as the direction of the input torque, i.e. opposite to the output torque provided to the first output shaft 403 in the first position and in the second position, respectively.

[0058] Figure 5 Another example of a torque transfer device 501 is illustrated. Figure 5 The illustrated torque transfer device differs from the torque transfer device 401 illustrated in Figures 3a to 3cThe torque transfer device shown differs in that the input shaft 502 is permanently drivingly connected with the ring gear 513 and the second output shaft 504 is selectively drivingly connected to the sun gear 511 via the first shift device 520. As with the Figures 3a to 3c The example shown is similar in that the first output shaft 503 is permanently drivingly connected with the ring gear 513 and is rotatably received in the input shaft 502. Figure 5 A first position of the first shift device 520 is shown, namely the four-wheel drive mode. The second and third positions (not shown) corresponding to the low-speed two-wheel drive mode and the direct two-wheel drive mode, respectively, are as referred to in Figures 3a to 3c the implementation. As with the Figures 3a to 3c The torque transfer device 501 shown has a smaller ratio step between the second and third positions of the first shift device 520 compared to the example shown.

[0059] In a further example, not shown, the input shaft can be connected to the planet carrier and the output shafts to the ring gear and the sun gear, respectively. This, however, would result in an overdrive ratio when the first shift device is in the second position, i.e. a torque reduction.

[0060] Figures 6a to 6d A further example of a torque transfer device 601 is shown, which is similar to the example shown in Figures 3a to 3c but in which a second shift device 640 is provided in addition to the first shift device 620. In this way, four drive modes can be implemented instead of three, as shown in Figures 6a to 6d

[0061] The second shift device 640 is formed here as a fixed connection with the sun gear 611, such that it moves the sun gear 611 back and forth along the axial direction and selectively connects it to the input shaft 602. The first shift device 620 and the second shift device 640 are configured to selectively switch the input gears for torque transfer via the torque transfer device 601.

[0062] The second shift device 640 can be selectively set in one of a locked position, in which it locks the sun gear 611 of the planetary gear system 610 to a fixed component 630 of the torque transfer device 601, such as to its housing, and an unlocked position, in which it unlocks the sun gear 611 from the fixed component 630 and instead locks it for co-rotation with the input shaft 602.

[0063] Figure 6a ​The torque transfer device 601 is shown in a first drive mode in the form of a four-wheel drive mode, in which both output shafts 603, 604 are driven. The first shift device 620 is in a first position, drivingly connecting the ring gear 613 to the second output shaft 604. The second shift device 640 is in an unlocked position.

[0064] Figure 6b The second drive mode is shown in the form of a low-speed gear drive mode, in which the first shift device 620 is in a second position, and the second shift device 640 is in an unlocked position. Only the first output shaft 603 is driven.

[0065] Figure 6c The third drive mode is shown in the form of a reduction drive mode, in which the first shift device 620 is in a third position, locking the ring gear 613 for co-rotation with the input shaft 602 and drivingly disconnecting the second output shaft 604 from the ring gear 613. The second shift device 640 is in a locked position. This means that the input torque is supplied to the ring gear 613, and not to the sun gear 611. Only the first output shaft 603 is driven. The output torque is lower than the output torque provided in the second drive mode, but higher than in the direct drive mode.

[0066] Figure 6d The fourth drive mode is shown in the form of a direct drive mode, in which the first shift device 620 is in a third position, locking the ring gear 613 for co-rotation with the input shaft 602 and drivingly disconnecting the second output shaft 604 from the ring gear 613. The second shift device 640 is in an unlocked position. Only the first output shaft 603 is driven, with a direct drive ratio.

[0067] Figures 7a to 7c The fourth drive mode is shown in the form of a direct drive mode, in which the first shift device 620 is in a third position, locking the ring gear 613 for co-rotation with the input shaft 602 and drivingly disconnecting the second output shaft 604 from the ring gear 613. The second shift device 640 is in an unlocked position. Only the first output shaft 603 is driven, with a direct drive ratio. Figures 3a to 3c An alternative configuration of the torque transfer device 1 is shown in Figures 3a to 3c , in which the arrangement of the input shaft 2, the first output shaft 3 and the second output shaft 4 differs from the example shown in Figure 7a . A first alternative is shown, in which the second output shaft 4 is a hollow shaft rotatably receiving the first output shaft 3. Figure 7b A second alternative is shown, in which the first output shaft 3 is a hollow shaft rotatably receiving the input shaft 2. Figure 7c A third alternative is shown, in which the second output shaft 4 is a hollow shaft rotatably receiving the input shaft 2.

[0068] In all examples, the first and second shift devices can be controlled by using one or more actuators (not shown), such as hydraulic, electric or pneumatic actuators, i.e. moved axially back and forth. The one or more actuators can be controlled automatically by a transmission control unit (not shown) and / or controlled based on input from a user, e.g. a driver of the vehicle 100. Respective shift forks (not shown) can also be provided between the first and second shift devices and the one or more actuators. The first and second shift devices can be in the form of sleeves.

[0069] Figure 8 A vehicle, such as a truck, is shown. The vehicle 100 is shown in a side view in Fig. 1. The vehicle 100 comprises a powertrain 110, a first axle 101 and a second axle 102. The powertrain 110 comprises a prime mover 103 in the form of an internal combustion engine configured to provide propulsion power for driving the vehicle 100. The prime mover 103 is drivingly connected to the axles 101, 102 via a torque transfer device 1. An input shaft 2 transmits input torque, generated by the prime mover 103 and converted in a transmission 120, to the torque transfer device 1. The torque is further transmitted via a first output shaft 3 to the first axle 101, such as a front axle, and via a second output shaft 4 to the second axle 102, such as a rear axle. Figure 1 An alternative configuration of a powertrain 110’ of a vehicle, such as a truck, is shown. The vehicle 100 is shown in a side view in Fig. 1. The vehicle 100 comprises a powertrain 110’, a first axle 101 and a second axle 102. The powertrain 110’ comprises a prime mover 103’ in the form of an internal combustion engine configured to provide propulsion power for driving the vehicle 100. The prime mover 103’ is drivingly connected to the axles 101, 102 via a torque transfer device 1. An input shaft 2 transmits input torque, generated by the prime mover 103’ and converted in a transmission 120, to the torque transfer device 1. The torque is further transmitted via a first output shaft 3 to the first axle 101, such as a front axle, and via a second output shaft 4 to the second axle 102, such as a rear axle.

[0070] Although the vehicle 100 is shown herein in the form of a tractor truck, the vehicle can be any type of vehicle in which it is desirable to distribute torque between at least two axles, such as a truck, a bus or a working machine. In some examples, the vehicle can comprise a tandem rear axle, wherein one of the output shafts 3, 4 can drive the tandem rear axle. In other examples, the vehicle can be a combination vehicle comprising a tractor vehicle and a trailer, wherein the first axle is provided on the tractor vehicle and the second axle is provided on the trailer.

[0071] In the following, possible features and combinations of features of the present disclosure are presented as a series of numbered examples:

[0072] Example 1. A torque transfer device (1, 401, 501, 601) configured to distribute torque from an input shaft (2, 402, 502, 602) to a first output shaft and a second output shaft (3, 403, 503, 603; 4, 404, 504, 604) configured to drive a first axle and a second axle (101, 102) of a vehicle (100) respectively, wherein the torque transfer device comprises: a planetary gear system (10, 410, 510, 610) comprising a sun gear (11, 411, 511), a ring gear (13, 413, 513) and a planet carrier (12, 412, 512) carrying a plurality of planet gears (14, 414); and a first shift device (20, 420, 520, 620) selectively settable to one of a first position, a second position and a third position, wherein:

[0073] - in the first position, the torque transfer device (1, 401, 501, 601) is configured to provide an output torque to the first and second output shafts (3, 403, 503, 603; 4, 404, 504, 604) via the planetary gear system (10, 410, 510, 610), the output torque to each of the output shafts (3, 403, 503, 603; 4, 404, 504, 604) being greater than an input torque provided via the input shaft (2),

[0074] - in the second position, the torque transfer device (1, 401, 501, 601) is configured to provide an output torque to only the first output shaft (3, 403, 503, 603), the output torque being greater than the input torque, and

[0075] - in the third position, the torque transfer device (1, 401, 501, 601) is configured to provide an output torque to only the first output shaft (3, 403, 503, 603) at a direct drive ratio or at a drive ratio lower than in the second position.

[0076] Example 2. The torque transfer device according to example 1, wherein the input shaft (2, 402, 502, 602) is drivingly connected to the first output shaft (3, 403, 503, 603) via a first gear (11, 411, 513, 611) and a second gear (12, 413, 512, 612) of the planetary gear system (10, 410, 510, 610).

[0077] Example 3. The torque transfer device according to example 1 or 2, wherein in the first position the first shift device (20, 420, 520, 620) is configured to lock the second output shaft (4, 404, 504, 604) for co-rotation with a third gear wheel (13, 412, 511, 613) of the planetary gear system (10, 410, 510, 610).

[0078] Example 4. The torque transfer device according to example 3, wherein in the second position the first shift device (20, 420, 520, 620) is configured to lock the third gear wheel (13, 412, 511, 613) to a stationary member (30, 430, 630) of the torque transfer device (1, 401, 501, 601), such as to a housing, and to driveably disconnect the second output shaft (4, 404, 504, 604) from the third gear wheel (13, 412, 511, 613).

[0079] Example 5. The torque transfer device according to example 3 or 4, wherein in the third position the first shift device (20, 420, 520, 620) is configured to lock the third gear wheel (13, 412, 511, 613) for co-rotation with the first gear wheel (11, 411, 513) and / or the input shaft (2, 402, 502, 602), and to driveably disconnect the second output shaft (4, 404, 504, 604) from the third gear wheel (13, 412, 511, 613).

[0080] Example 6. The torque transfer device according to any of the preceding examples, wherein the input shaft (2, 402) is fixed for co-rotation with the central gear wheel (11, 411), or wherein the input shaft (602) is configured to be fixed for co-rotation with the central gear wheel (611) via a second shift device (640).

[0081] Example 7. The torque transfer device according to example 6, wherein the first output shaft (3, 503, 603) is fixed for co-rotation with the planetary gear carrier (12, 512, 612), and wherein the second output shaft (4, 504, 604) is selectively connectable to the ring gear (13, 513, 613) via the first shift device (20, 520, 620).

[0082] Example 8. The torque transfer device according to example 7, wherein the first shift device (20) is configured to selectively lock the ring gear (13, 513, 613) to a stationary member (30, 630) of the torque transfer device (1, 501, 601), such as a housing.

[0083] Example 9. The torque transfer device according to example 6, wherein the first output shaft (403) is fixed for co-rotation with the ring gear (413), and wherein the second output shaft (404) is selectively connectable to the spider gear carrier (412) via the first shift device (420).

[0084] Example 10. The torque transfer device according to any of the preceding examples, wherein the input shaft (2, 402, 502, 602) and the first and second output shafts (3, 403, 503, 603; 4, 404, 504, 604) are coaxially arranged.

[0085] Example 11. The torque transfer device according to any of the preceding examples, wherein the input shaft (2, 402, 502, 602) is a hollow shaft configured to receive the first output shaft (3, 403, 503, 603).

[0086] Example 12. The torque transfer device according to any of examples 1 to 10, wherein the second output shaft (4) is a hollow shaft configured to receive one of the input shaft (2) and the first output shaft (4).

[0087] Example 13. The torque transfer device according to any of examples 1 to 10, wherein the first output shaft (3) is a hollow shaft configured to receive the input shaft (2).

[0088] Example 14. The torque transfer device according to any of the preceding examples, further comprising a second shift device (640), the first and second shift devices (620, 640) being configured to selectively switch the input gear for torque transfer via the torque transfer device (601).

[0089] Example 15. The torque transfer device according to example 14, wherein the second shift device (640) is selectively settable in one of a locked position, in which the second shift device locks a first gear (611) of the planetary gear system (610) to a stationary member (630) of the torque transfer device (601), such as to a housing, and an unlocked position, in which the second shift device unlocks the first gear (611) from the stationary member (630) and locks it for co-rotation with the input shaft (602).

[0090] Example 16. The torque transfer device according to example 15, wherein the first gear (611) is the sun gear.

[0091] Example 17. The torque transfer device according to example 15 or 16, wherein the torque transfer device (601) is configured to provide four drive modes, including:

[0092] - a four-wheel drive mode, in which the first shift device (620) is in the first position and the second shift device (640) is in the unlocked position,

[0093] - a low-speed gear drive mode, in which the first shift device (620) is in the second position and the second shift device (640) is in the unlocked position,

[0094] - a step-down drive mode, in which the first shift device (620) is in the third position and the second shift device (640) is in the locked position, and

[0095] - a direct drive mode, in which the first shift device (620) is in the third position and the second shift device (640) is in the unlocked position,

[0096] Example 18. The torque transfer device according to any of the preceding examples, wherein at least the first shift device (620) comprises a sleeve configured to be actuated by an actuation device, such as a shift fork.

[0097] Example 19. A powertrain system (110) for a vehicle, comprising a torque transfer device according to any of the preceding examples, at least one prime mover (103), and a first and a second axle (101, 102), wherein the input shaft (2) is drivingly connected to the at least one prime mover (103), and wherein the first and second output shafts (3, 4) are arranged for driving the first and second axles (101, 102), respectively.

[0098] Example 20. A vehicle (100) comprising a powertrain (110) according to example 19.

[0099] The terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting of the present disclosure. As used herein, the singular forms "a," "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. It will be understood by those within the art that, in general, terms used herein, and especially

[0100] It will be understood that, although the terms first, second, etc. can be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of the present disclosure.

[0101] Relative terms such as "below" or "above" or "upper" or "lower" or "horizontal" or "vertical" can be used herein to describe a relationship of one element to another as illustrated in the figures. It will be understood that these terms and those discussed above are intended to encompass different orientations of the device in addition to the orientation depicted in the figures. It is to be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element or intervening elements can be present. In contrast, when an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements present.

[0102] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0103] It will be understood that the present disclosure is not limited to the aspects described above and shown in the attached drawings; rather, the skilled person will recognize that many changes and modifications can be made within the scope of the present disclosure and the appended claims. The aspects have been disclosed for purposes of illustration and, therefore, modification and alternative forms of aspects will be apparent to others skilled in the art without departing from the scope thereof, which is defined in the appended claims.

Claims

1. A torque transfer device (1, 401, 501, 601) configured to distribute torque from an input shaft (2, 402, 502, 602) to first and second output shafts (3, 403, 503, 603; 4, 404, 504, 604) configured to drive first and second axles (101, 102) of a vehicle (100), respectively, wherein the torque transfer device comprises: A planetary gear system (10, 410, 510, 610) comprising a sun gear (11, 411, 511), a ring gear (13, 413, 513) and a planet carrier (12, 412, 512) carrying a plurality of planet gears (14, 414); and a first shift device (20, 420, 520, 620) selectively settable into one of a first position, a second position and a third position, wherein: - in the first position, the torque transfer device (1, 401, 501, 601) is configured to provide an output torque to the first and second output shafts (3, 403, 503, 603; 4, 404, 504, 604) via the planetary gear system (10, 410, 510, 610), the output torque to each of the output shafts (3, 403, 503, 603; 4, 404, 504, 604) being greater than an input torque provided via the input shaft (2), - in the second position, the torque transfer device (1, 401, 501, 601) is configured to provide an output torque to the first output shaft (3, 403, 503, 603) only, the output torque being greater than the input torque, and - in the third position, the torque transfer device (1, 401, 501, 601) is configured to provide an output torque to the first output shaft (3, 403, 503, 603) only, either at a direct drive ratio or at a drive ratio lower than in the second position.

2. The torque transfer device according to claim 1, wherein the input shaft (2, 402, 502, 602) is drivingly connected to the first output shaft (3, 403, 503, 603) via a first gear (11, 411, 513, 611) and a second gear (12, 413, 512, 612) of the planetary gear system (10, 410, 510, 610).

3. The torque transfer device according to claim 1 or 2, wherein in the first position, the first shift device (20, 420, 520, 620) is configured to lock the second output shaft (4, 404, 504, 604) for co-rotation with a third gear (13, 412, 511, 613) of the planetary gear system (10, 410, 510, 610).

4. The torque transfer device according to claim 3, wherein in the second position the first shift device (20, 420, 520, 620) is configured to lock the third gear wheel (13, 412, 511, 613) to a stationary member (30, 430, 630) of the torque transfer device (1, 401, 501, 601), such as to a housing, and to driveably disconnect the second output shaft (4, 404, 504, 604) from the third gear wheel (13, 412, 511, 613).

5. The torque transfer device according to claim 3 or 4, wherein in the third position the first shift device (20, 420, 520, 620) is configured to lock the third gear wheel (13, 412, 511, 613) for co-rotation with the first gear wheel (11, 411, 513) and / or the input shaft (2, 402, 502, 602) and to driveably disconnect the second output shaft (4, 404, 504, 604) from the third gear wheel (13, 412, 511, 613).

6. The torque transfer device according to any one of the preceding claims, wherein the input shaft (2, 402) is fixed for co-rotation with the central gear wheel (11, 411), or wherein the input shaft (602) is configured to be fixed for co-rotation with the central gear wheel (611) via a second shift device (640).

7. The torque transfer device according to claim 6, wherein the first output shaft (3, 503, 603) is fixed for co-rotation with the planet carrier (12, 512, 612), and wherein the second output shaft (4, 504, 604) is selectively connectable to the ring gear (13, 513, 613) via the first shift device (20, 520, 620).

8. The torque transfer device according to claim 7, wherein the first shift device (20) is configured to selectively lock the ring gear (13, 513, 613) to a stationary member (30, 630) of the torque transfer device (1, 501, 601), such as a housing.

9. The torque transfer device according to claim 6, wherein the first output shaft (403) is fixed for co-rotation with the ring gear (413), and wherein the second output shaft (404) is selectively connectable to the sun gear carrier (412) via the first shift device (420).

10. The torque transfer device according to any one of the preceding claims, wherein the input shaft (2, 402, 502, 602) and the first and second output shafts (3, 403, 503, 603; 4, 404, 504, 604) are coaxially arranged.

11. The torque transfer device according to any one of the preceding claims, wherein the input shaft (2, 402, 502, 602) is a hollow shaft configured to receive the first output shaft (3, 403, 503, 603).

12. The torque transfer device according to any one of the preceding claims, further comprising a second shift device (640), the first and second shift devices (620, 640) being configured to selectively switch the input gear for torque transfer via the torque transfer device (601).

13. The torque transfer device according to claim 12, wherein the second shift device (640) is selectively settable in one of a locked position, in which the second shift device locks a first gear (611) of the planetary gear system (610) to a stationary member (630) of the torque transfer device (601), such as to a housing, and an unlocked position, in which the second shift device unlocks the first gear (611) from the stationary member (630) and locks it for co-rotation with the input shaft (602).

14. A powertrain system (110) for a vehicle, comprising a torque transfer device according to any one of the preceding claims, at least one prime mover (103), and first and second vehicle axles (101, 102), wherein the input shaft (2) is drivingly connected to the at least one prime mover (103), and wherein the first and second output shafts (3, 4) are arranged for driving the first and second vehicle axles (101, 102), respectively.

15. A vehicle (100) comprising a powertrain system (110) according to claim 14.

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