Differential gear arrangement with three planetary gear sets and torque vectoring actuator, as well as drivetrain for a motor vehicle with such a

Abstract

The invention relates to a differential gear arrangement with a housing arrangement (40) in which an input shaft (8), a first and second output shaft (42, 44) and at least one first, second and third planet gear set (10, 12, 14) are rotatably mounted, wherein each planet gear set (10, 12, 14) has at least one planet carrier (16, 18, 20) on which several rotatably mounted planet gears (22, 24; 52, 56, 26; 54, 58) are provided, which mesh with a sun gear (28, 30, 32) and a ring gear (34, 36, 38), wherein the planet gear sets (10, 12, 14) are operatively connected to the output shafts (42, 44), wherein the third planet gear set (14) together with an actuator (48) forms a torque vectoring superposition unit (46), wherein the actuator (48) is operatively connected to the third planet carrier (20) of the third planet gear set (38),wherein the input shaft (8) is operatively connected to the first sun gear (28) of the first planet gear set (10), wherein the first planet carrier (16) of the first planet gear set (10) is operatively connected to the first output shaft (42) and the third planet gear set (14), wherein the second output shaft (44) is operatively connected to the second planet gear set (12), wherein the first ring gear (34) of the first planet gear set (10) is operatively connected to the second and third sun gears (30, 32) of the second and third planet gear sets (12, 14), and wherein the third planet gear set (14) is arranged axially between the first planet gear set (10) and the second planet gear set (12). The invention further relates to a drive train for a motor vehicle with a drive unit (4) which is operatively connected to the input shaft (8) of such a differential gear arrangement (2).

Description

[0001] The invention relates to a differential gear arrangement with a housing arrangement in which an input shaft, a first and second output shaft, and at least a first, second, and third planetary gear set are rotatably mounted, each planetary gear set having a planet carrier on which several rotatably mounted planet gears are provided, which mesh with a sun gear and a ring gear, the planetary gear sets being operatively connected to the output shafts, the third planetary gear set together with an actuator forming a torque-vectoring superposition unit, the actuator being rotationally fixed to the third planet carrier of the third planetary gear set, the input shaft being operatively connected to the first sun gear of the first planetary gear set, and the first planet carrier of the first planetary gear set being operatively connected to the first output shaft and the third planetary gear set.wherein the second output shaft is operatively connected to the second planetary gear set, wherein the first ring gear of the first planetary gear set is operatively connected to the second and third sun gears of the second and third planetary gear sets. Furthermore, the invention relates to a drive train for a motor vehicle with a drive unit that is operatively connected to the input shaft of such a differential gear arrangement.

[0002] The basic principle of such a differential gear arrangement is known, for example, from the international publication WO 2005 / 120877 A1. Due to its compact design, this differential gear arrangement is particularly suitable for use as an integral differential gear arrangement in combination with a drive unit for the powertrain of a motor vehicle. Further differential gear arrangements are known, for example, from DE 10 2018 119 001 A1 and DE 10 2019 209 465 A1. However, such a differential gear arrangement requires the use of a so-called torque vectoring superposition unit to enable active drive torque distribution. In this context, a particular embodiment of DE 10 2019 209 461 A1 is known in which the torque vectoring superposition unit is provided alongside a first and second planetary gear set of the differential gear arrangement.However, access to the torque vectoring superposition unit is severely restricted and therefore only conditionally suitable for assembly. It should also be noted that a differential gear arrangement is known from the subsequently published DE 10 2024 108 052 A1, in which a third planetary gear set is arranged axially between the first and second planetary gear sets.

[0003] The invention is based on the objective of further developing a differential gear arrangement or a drive unit in such a way that the above-mentioned problem is avoided in a simple manner.

[0004] The problem is solved by a differential gear arrangement according to claim 1. Further developments of the differential gear arrangement are the subject of the dependent claims.

[0005] This problem is solved by arranging the third planetary gear set axially between the first and second planetary gear sets, with a drive unit operatively connected to the input shaft via a gear stage and arranged offset from the axis, and the actuator positioned opposite the drive unit with respect to the planetary gear sets. This makes it possible to provide a very compact differential gear arrangement in both the radial and axial directions.

[0006] By connecting the actuator to the third planet carrier of the third planet gear set via a hollow spur gear, a simple, safe and easily accessible torque transmission is advantageously provided.

[0007] If the required gear ratio is not too high, the second and third planetary gear sets can be configured as negative gear sets, with the first planet carrier of the first planetary gear set being operatively connected to the third ring gear of the third planetary gear set, and the second output shaft being operatively connected to the second ring gear of the second planetary gear set. In this configuration, the actuator is operatively connected to the third planet carrier of the third planetary gear set via a hollow spur gear.

[0008] Alternatively, the second and third planetary gear sets can be configured as positive gear sets, with the first planet carrier of the first planetary gear set being operatively connected to the third planet carriers of the third planetary gear set, and the second output shaft being operatively connected to the second planet carriers of the second planetary gear set. In this configuration, two planet carriers are provided for each of the second and third planetary gear sets, each with two meshing planet gears connected in series. When a negative planetary gear set is replaced by a positive planetary gear set, the connections between the planet carrier and the ring gear are reversed. Additionally, the fixed gear ratio increases by one. For example, -1.3 becomes +2.3. In this configuration, the actuator is operatively connected to the third ring gear of the third planetary gear set via a spur gear.

[0009] The problem is also solved by a drive train for a motor vehicle with a drive unit that is operatively connected to the input shaft of such a designed differential gear arrangement.

[0010] The invention is explained in more detail with reference to a drawing. This drawing shows: Fig. 1 a simplified schematic representation of a first embodiment of a differential arrangement according to the invention connected to a drive unit of a drive train according to the invention, and Fig. 2 a simplified schematic representation of a second embodiment of a differential arrangement according to the invention connected to a drive unit of a drive train according to the invention.

[0011] Fig. Figure 1 shows a simplified schematic representation of a differential gear assembly 2 with a known drive unit 4, which drives an input shaft 8 via a gearbox 6. The differential gear assembly 2 and the drive unit 4 are part of a drive train for a motor vehicle (not shown in detail). The differential gear assembly 2 combines the functions of transmission and differential operation. The differential gear assembly 2 essentially consists of three planetary gear sets 10, 12, 14 arranged axially side by side. The first and second planetary gear sets 10, 12 are located laterally to the third planetary gear set 14. Each planetary gear set 10, 12, 14 has a planet carrier 16, 18, 20, on which several rotatably mounted planet gears 22, 24, 26 are provided.

[0012] The first, second, and third planet gears 22, 24, 26 mesh in a known manner with a first, second, and third sun gear 28, 30, 32 and a first, second, and third ring gear 34, 36, 38, respectively. The planet gear sets 10, 12, 14 are provided within a housing arrangement 40, which is shown only schematically, and in which the input shaft 8, a first output shaft 42, and a second output shaft 44 are rotatably mounted. The first output shaft 42 is driven directly via the first planet carrier 16, and the second output shaft 44 via the second ring gear 36, with the first ring gear 34 being directly connected to the second sun gear 30.

[0013] To enable active drive torque distribution, a torque vectoring superposition unit 46 is provided, which essentially consists of the third planetary gear set 14 and an actuator 48 operatively connected to it, which here is designed as a second electric motor. The second electric motor 48 is operatively connected to the third planet carrier 20 via a gear 50 in order to distribute drive torque to the output shafts 42, 44 in a known manner, wherein the third ring gear 38 of the third planetary gear set 14 is operatively connected to the first planet carrier 16 and the third sun gear 32 of the third planetary gear set 14 is operatively connected to the first ring gear 34. It should be clear that other connections between the electric motor 48 and the planet carrier 20 are also possible.The embodiment shown here corresponds to a negative gear with second planet gears 24, which have a small diameter, resulting in a low overall gear ratio of the differential gear arrangement 2.

[0014] To achieve a higher overall gear ratio of the differential gear arrangement 2, according to Fig.2. The second planet gear set 12 together with the third planet gear set 14 can also be configured as a plus gear set, wherein an inner second and third planet gear 52, 54, which mesh with the second and third sun gears 30, 32, and an outer second and third planet gear 56, 58, which mesh with the inner planet gears 52, 54 and the second, housing-fixed, and the third ring gear 38, are provided. In this embodiment, the second planet carriers 18 are operatively connected to the second output shaft 44, and the first planet carrier 16 of the first planet gear set 10 is operatively connected to the third planet carriers 20 of the third planet gear set 14. In this case, the actuator 48 is operatively connected to the third ring gear 38 of the third planet gear set 14 via the ring spur gear 50.

Claims

[1] Differential gear arrangement with a housing arrangement (40) in which an input shaft (8), a first and second output shaft (42, 44) and at least one first, second and third planet gear set (10, 12, 14) are rotatably mounted, wherein each planet gear set (10, 12, 14) has at least one planet carrier (16, 18, 20) on which several rotatably mounted planet gears (22, 24; 52, 56, 26;54, 58) are provided, which are in tooth mesh with a sun gear (28, 30, 32) and a ring gear (34, 36, 38), wherein the planet gear sets (10, 12, 14) are operatively connected to the output shafts (42, 44), wherein the third planet gear set (14) together with an actuator (48) forms a torque vectoring superposition unit (46), wherein the actuator (48) is operatively connected to the third planet carrier (20) of the third planet gear set (14), wherein the input shaft (8) is operatively connected to the first sun gear (28) of the first planet gear set (10), wherein the first planet carrier (16) of the first planet gear set (10) is operatively connected to the first output shaft (42) and the third planet gear set (14), wherein the second output shaft (44) is operatively connected to the second planet gear set (12) is operatively connected, wherein the first ring gear (34) of the first planet gear set (10) is operatively connected to the second and third sun gears (30, 32) of the second and third planet gear set (12, 14), ;characterized by , that the third planet gear set (14) is arranged axially between the first planet gear set (10) and the second planet gear set (12), wherein a drive unit (4) is operatively connected to the input shaft (8) via a gear stage (6) and is arranged offset from the axis and the actuator (48) is arranged opposite the drive unit (4) with respect to the planet gear sets (10, 12, 14). [2] Differential gear arrangement according to one of the preceding claims, characterized by , that the second planet gear set (12) and third planet gear set (14) are designed as a negative gear set, wherein the first planet carrier (16) of the first planet gear set (10) is operatively connected to the third ring gear (38) of the third planet gear set (14), wherein the second output shaft (44) is operatively connected to the second ring gear (36) of the second planet gear set (12). [3] Differential gear arrangement according to claim 2, characterized by, that the actuator (48) is operatively connected to the third planet carrier (20) of the third planet gear set (14) via a hollow spur gear (50). [4] Differential gear arrangement according to claim 1, characterized by , that the second planet gear set (12) and third planet gear set (14) are designed as a plus gear set, wherein the first planet carrier (16) of the first planet gear set (10) is operatively connected to the third planet carriers (20) of the third planet gear set (14), wherein the second output shaft (44) is operatively connected to the second planet carriers (18) of the second planet gear set (12). [5] Differential gear arrangement according to claim 4, characterized by , that the actuator (48) is operatively connected to the third ring gear (38) of the third planetary gear set (14) via a hollow spur gear (50). [6] Drive train for a motor vehicle comprising a drive unit (4) which is operatively connected to the input shaft (8) of a differential gear arrangement (2) according to one of the preceding claims.

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