A TORQUE VECTORING DEVICE, AND A DRIVE AXLE FOR A VEHICLE WITH A TORQUE VECTORING DEVICE

Abstract

The disclosed invention refers to a torque vectoring device (30) for a drive axle (12) of a vehicle (10). The torque vectoring device (30) comprises an electric torque vectoring motor (32), a planetary gear (34) and a layshaft (36) being configured to be coupled to a cage (26) of a differential gear (24), said planetary gear (34) comprising a first output being configured to be coupled to one of a left or right wheel drive shaft (16; 18) and a second output being coupled to said layshaft (36). The torque vectoring motor (32) is forming a first torque flow path (38) with said planetary gear (34) and said layshaft (36) and a second torque flow path (40) with the first output of said planetary gear (34), wherein said first torque flow path (38) and said second torque flow path (40) are kinematically arranged in parallel. The layshaft (36) is arranged eccentric with the first output of the planetary gear (34).

Claims

1. A torque vectoring device for a drive axle of a vehicle, said torque vectoring device comprising an electric torque vectoring motor, a planetary gear and a layshaft being configured to be coupled to a cage of a differential gear, said planetary gear comprising a first output being configured to be coupled to one of a left or right wheel drive shaft and a second output being coupled to said layshaft, wherein said torque vectoring motor is forming a first torque flow path with said planetary gear and said layshaft and a second torque flow path with the first output of said planetary gear, wherein said first torque flow path and said second torque flow path are kinematically arranged in parallel, wherein the layshaft is arranged eccentric with the first output of the planetary gear.

2. The torque vectoring device according to claim 1, wherein in use the planetary gear is arranged concentric with said wheel drive shafts.

3. The torque vectoring device according to claim 2, wherein the layshaft is axially arranged off said wheel drive shafts.

4. The torque vectoring device according to claim 1, wherein the torque vectoring motor is coupled to a sun gear of the planetary gear, while a planet carrier is configured to be coupled to said left or right wheel drive shaft, and the layshaft is coupled to a ring gear of the planetary gear.

5. The torque vectoring device according to claim 3, wherein the torque vectoring motor is coupled to a sun gear of the planetary gear, while a ring gear is configured to be coupled to said left or right wheel drive shaft, and the layshaft is coupled to a planet carrier of the planetary gear.

6. The torque vectoring device according to claim 5, wherein the layshaft is integrally formed by the planet carrier.

7. A drive axle for a vehicle, comprising a differential gear with a cage and with a left wheel drive shaft and a right wheel drive shaft extending from said differential gear, and the torque vectoring device according to claim 1.

8. The drive axle according to claim 7, wherein the differential gear comprises a spur gear differential or a bevel gear differential.

9. The drive axle according to claim 8, wherein the differential gear comprises a spur gear differential and a planet carrier, forming the first output of the planetary gear, is coupled to a planet spur gear of said spur gear differential.

10. The drive axle according to claim 9, further comprising an electric traction motor coupled to the cage of the differential gear, wherein the torque vectoring motor and/or the traction motor are arranged concentric with the wheel drive shafts.

11. A vehicle, comprising at least one drive axle according to claim 7.

12. The torque vectoring device according to claim 1, wherein the layshaft is axially arranged off said wheel drive shafts.

13. The torque vectoring device according to claim 1, wherein the torque vectoring motor is coupled to a sun gear of the planetary gear, while a ring gear is configured to be coupled to said left or right wheel drive shaft, and the layshaft is coupled to a planet carrier of the planetary gear.

14. The torque vectoring device according to claim 13, wherein the layshaft is integrally formed by the planet carrier.

15. The drive axle according to claim 7, wherein the differential gear comprises a spur gear differential and a planet carrier, forming the first output of the planetary gear, is coupled to a planet spur gear of said spur gear differential.

16. The drive axle according to claim 7, further comprising an electric traction motor coupled to the cage of the differential gear, wherein the torque vectoring motor and/or the traction motor are arranged concentric with the wheel drive shafts.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The invention will be described in further detail below with reference to the accompanying drawings, in which

[0046] FIG. 1 is a schematic view of an embodiment of a vehicle; and

[0047] FIG. 2-7 are schematic views of embodiments of a drive axle.

DETAILED DESCRIPTION

[0048] Starting with FIG. 1, a schematic view of an embodiment of an inventive vehicle 10 is illustrated. Said vehicle 10 can have one or more drive axles 12 being provided with a torque vectoring device according to the invention. However, optionally there may be one or more drive axles 14 of a different type in addition, for example driven by a combustion engine. The arrangement of the inventive drive axle(s) 12 and optional drive axle(s) 14 can be freely chosen. The drive axle 12 has a left wheel drive shaft 16 and a right wheel drive shaft 18. For use in the vehicle 10, one or more wheels can be applied to the left wheel drive shaft 16 and a right wheel drive shaft 18, that are referred to as a left wheel 20 and a right wheel 22, respectively.

[0049] In FIG. 2, common features of all embodiments of the inventive torque vectoring device and/or drive axle 12 for the vehicle 10 are described and a specific embodiment is schematically illustrated. The drive axle 12 comprises a differential gear 24 with a cage 26. Further, the drive axle 12 comprises an electric traction motor 28 coupled to said cage 26. The left wheel drive shaft 16 and the right wheel drive shaft 18 extend from said differential gear 24. The wheel drive shafts 16, 18 are also considered the axis of rotational symmetry, with respect to those components illustrated symmetrical with regard to the wheel drive shafts 16, 18.

[0050] The drive axle 12 further comprises a torque vectoring device 30 with an electric torque vectoring motor 32, a planetary gear 34 and a layshaft 36.

[0051] The planetary gear 34 is coupled to one of said wheel drive shafts 16, 18. In this illustration, just as an example, it is coupled to the left wheel drive shaft 16. However, it is clear, that left or right refers to an orientation, in which the drive axle 12 is assembled in the vehicle 10.

[0052] Further, the layshaft 36 is coupled to the cage 26. Based on the described arrangements, the torque vectoring motor 32 is forming a first torque flow path 38 with the planetary gear 34, the layshaft 36 and the cage 26 and a second torque flow path 40 with said planetary gear 34 and the left wheel drive shaft 16. As can be seen in FIG. 2, the first torque flow path 38 and the second torque flow path 40 are kinematically arranged in parallel.

[0053] If additional torque 42 is to be supplied by the torque vectoring motor 32, it is passed on via the first torque flow path 38 to the cage 26 and via the second torque flow path 40 to the left wheel drive shaft 16.

[0054] At the same time, the traction motor 28 can deliver a traction torque 44 to the cage 26. This traction torque 44 is superimposed with the additional torque 42 in the differential gear 24 and both are delivered to the left and right wheel drive shaft 16, 18 due to rotation of the cage 26.

[0055] At the same time, the additional torque 42 is directly supplied to the left wheel drive shaft 16, to which the planetary gear 34 is coupled, in the second torque flow path 40. As a result, the left wheel drive shaft 16 obtains more additional torque 42 (which can be positive or negative with regard to the traction torque 44) via both, the first and second torque flow path 38, 40, than the right wheel drive shaft 18 that only receives additional torque 42 via the first torque flow path 38.

[0056] This means an overall torque 46 in the left wheel drive shaft 16 is a superposition of said traction torque 44, said additional torque 42 via the first torque flow path 38 and said additional torque 42 via the second torque flow path 40, whereas an overall torque 48 in the right wheel drive shaft 18 is a superposition of only said traction torque 44 and said additional torque 42 supplied via the first torque flow path 38.

[0057] Accordingly, the additional torque 42 delivered by the torque vectoring motor 32 has a stronger influence on the overall torque 46 in the left wheel drive shaft 16 than in the right wheel drive shaft 18. This stronger influence is illustrated by thick arrows and a thick torque flow path line at reference sign 46. Thus, the overall torques 46 and 48 in the left and right wheel drive shafts 16, 18 can be influenced relatively to each other, according to the requirements of the driving situation and by appropriate control of the torque vectoring motor 32 (the controller is not shown here).

[0058] Merely for simpler illustration, the torque flow lines of the first and second torque flow paths 38, 40 are only illustrated in the upper part of the figure, with regard to the axis of rotational symmetry.

[0059] The essential principles described above apply to all embodiments of the drive axle 12 of the invention, despite the physical structure having some specific differences in the different embodiments. Therefore, the above description applies to the other figures, as well, with regard to these principles.

[0060] Now turning to the specific aspects of the embodiment shown in FIG. 2, the planetary gear 34 is arranged concentric with the wheel drive shafts 16, 18.

[0061] The torque vectoring motor 32 is coupled to an input in the form of a sun gear 50 of the planetary gear 34 via a gear connection 64, while the left wheel drive shaft 16 is coupled to a planet carrier 52 of the planetary gear 34, forming a first output of the planetary gear 34. The layshaft 36, which is arranged eccentric with the planetary gear 34 such that it is arranged off-axis, is coupled to a ring gear 54 of the planetary gear 34, forming a second output of the planetary gear 34.

[0062] In this example, the differential gear 24 comprises a bevel gear differential 58, however, it could also comprise a spur gear differential 60 (see FIGS. 5 and 6). Further, the torque vectoring motor 32 is arranged off-axis with regard to the wheel drive shafts 16, 18, while the traction motor 28 is arranged concentric with those.

[0063] Now turning to FIG. 3, another embodiment of the inventive drive axle 12 is schematically illustrated in a simplified manner, focussing on the specific aspects of this embodiment.

[0064] Herein, the planetary gear 34 again is arranged concentric with the wheel drive shafts 16, 18 while the layshaft 36 is arranged off-axis, or eccentric with the planetary gear 34. The torque vectoring motor 32 is coupled to the sun gear 50 via a gear connection 64 and is forming the second torque flow path 40 with the planetary gear 34 and the left wheel drive shaft 16 via the ring gear 54, which in this embodiment forms the first output of the planetary gear 34. The left wheel drive shaft 16 is therefore coupled to the ring gear 54 of the planetary gear 34. The first torque flow path 38 is formed by the torque vectoring motor 32 via the sun gear 50, the planet carrier 52 and the layshaft 36 being coupled to the planet carrier 52 of the planetary gear 34. Hence, here the planet carrier 52 forms the second output of the planetary gear 34. In this embodiment, the differential gear 24 comprises a bevel gear differential 58.

[0065] Now turning to FIG. 4, another embodiment of the inventive drive axle 12 is schematically illustrated in a simplified manner, focussing on the specific aspects of this embodiment.

[0066] Again, the planetary gear 34 is arranged concentric with the wheel drive shafts 16, 18 while the layshaft 36 is arranged eccentric with the planetary gear 34. The torque vectoring motor 32 is forming the second torque flow path 40 with the planetary gear 34 and the left wheel drive shaft 16 via the ring gear 54. The torque vectoring motor 32 is coupled to the sun gear 50. The left wheel drive shaft 16 is further coupled to the ring gear 54 of the planetary gear 34 which forms the first output of the planetary gear 34. The layshaft 36 is coupled to the planet carrier 52 of the planetary gear 34 which forms the second output of the planetary gear 34. The first torque flow path 38 is thus formed via the sun gear 50, the planet carrier 52 and the layshaft 36. The differential gear 24 comprises a bevel gear differential 58. In this embodiment, the electric traction motor 28 is coupled to the cage 26 via said layshaft 36.

[0067] Now turning to FIG. 5, the specific aspects of this embodiment again comprise, that the planetary gear 34 is arranged concentric with the wheel drive shafts 16, 18 while the layshaft 36 is axially offset from the planetary gear 34. The torque vectoring motor 32 is coupled to the sun gear 50 of the planetary gear 34 and is arranged concentric with the planetary gear 34. In this embodiment, this is done in a manner that the torque vectoring motor 32 is arranged at an outer circumference of the sun gear 50. The traction motor 28 is arranged concentric with the wheel drive shafts 16, 18, as well.

[0068] In this example, the differential gear 24 comprises a spur gear differential 60. The left wheel drive shaft 16 is indirectly coupled to the planet carrier 52 of the planetary gear 34, forming the first output of the planetary gear 34, via a planet spur gear 62 of said spur gear differential 60. Said planet spur gear 62 extends out of the cage 26 and engages with the planet carrier 52. The layshaft 36 is coupled to the ring gear 54 of the planetary gear 34, which forms the second output of the planetary gear 34.

[0069] In this arrangement, the first torque flow path 38 is formed via the sun gear 50, the ring gear 54 and the layshaft 36. The second torque flow path 40 is formed via the sun gear 50, the planet carrier 52, and the planet spur gear 62.

[0070] Now turning to FIG. 6, one embodiment is described very similar to that of FIG. 5. Accordingly, only the difference will be highlighted and it is referred to FIG. 5 for other specific details.

[0071] As shown in FIG. 6, the torque vectoring motor 32 is again coupled to the sun gear 50 of the planetary gear 34 and is arranged concentric with the planetary gear 34. However, in this case the torque vectoring motor 32 is arranged in front of the planetary gear 34, still concentric with the wheel drive shafts 16, 18.

[0072] Now turning to FIG. 7, an embodiment is shown, wherein the planetary gear 34 is arranged axially off the left and right wheel drive shafts 16, 18. The torque vectoring motor 32 is coupled to the sun gear 50 of the planetary gear 34. The left wheel drive shaft 16 is coupled to the ring gear 54 of the planetary gear 34 by means of a gear connection 64, that can be integrated in these components.

[0073] The layshaft 36 is part of the planet carrier 52 in this embodiment and can be integrally formed by the planet carrier 52. The layshaft 36 engages with the cage 26, that has a counter-part to form a gear connection 64 with the layshaft 36. The counter-part can be integrally formed by the cage 26, as well.

[0074] In this arrangement, the first torque flow path 38 is formed via the sun gear 50, the planet carrier 52 and the layshaft 36 (which can be the planet carrier 52). The second torque flow path 40 is formed via the sun gear 50, the ring gear 54, and the gear connection 64.

[0075] In this example, the differential gear 24 comprises a bevel gear differential 58, however, it could also comprise a spur gear differential 60 (see FIGS. 5 and 6). Further, the torque vectoring motor 32 is arranged off-axis with regard to the wheel drive shafts 16, 18, while the traction motor 28 is arranged concentric with those.

[0076] For all embodiments described herein the layshaft 36 is preferably configured to i) bridge the axial distance between the planetary gear 34 and the differential gear 24, and ii) provide a gear change of the second output of the planetary gear 34.