Transmission for a Vehicle, and Drive Train Having Such a Transmission

Abstract

A transmission (3) for a drive train (2) includes a differential (7) arranged spatially within a housing part (11). The differential includes a first planetary gear set (29) and at least one second planetary gear set (30), which is operatively connected to the first planetary gear set. The housing part (11) includes at least one lubricant feed (15) configured for fluidically connecting a lubricant supply of the transmission (3) to an annular duct (46) formed, at least partially circumferentially, spatially between a planet carrier (32b) of the second planetary gear set (30) and the housing part (11). The planet carrier (32b) of the second planetary gear set (30) is arranged on the housing part (11) in a rotationally fixed and axially secured manner.

Claims

1-15: (canceled)

16. A transmission (3) for a drive train (2) of a vehicle (1), comprising: a housing part (11); a differential (7) arranged within the housing part (11), the differential comprising a first planetary gear set (29) and a second planetary gear set (30), the second planetary gear set (30) operatively connected to the first planetary gear set (29), wherein the housing part (11) comprises a lubricant feed (15) configured to fluidically connect a lubricant supply of the transmission (3) to an annular duct (46) formed, at least partially circumferentially, spatially between a planet carrier (32b) of the second planetary gear set (30) and the housing part (11), and wherein the planet carrier (32b) of the second planetary gear set (30) is rotationally fixed and axially secured on the housing part (11).

17. The transmission (3) of claim 16, wherein the planet carrier (32b) of the second planetary gear set (30) is connected to the housing part (11) for conjoint rotation via a driving tooth system (35).

18. The transmission (3) of claim 16, further comprising a securing ring (36) configured to axially secure the planet carrier (32b) of the second planetary gear set (30).

19. The transmission (3) of claim 18, wherein a radial projection (42) on the planet carrier (32b) of the second planetary gear set (30) is arranged axially between the securing ring (36) and an axial stop (37) on the housing part (11).

20. The transmission (3) of claim 16, wherein the planet carrier (32b) of the second planetary gear set (30) is radially secured on the housing part (11) via at least one centering (41).

21. The transmission (3) of claim 20, wherein: the planet carrier (32b) of the second planetary gear set (30) is connected to the housing part (11) for conjoint rotation via a driving tooth system (35); and wherein the driving tooth system (35) is arranged axially between the securing ring (36) and the centering (41).

22. The transmission (3) of claim 20, wherein: the planet carrier (32b) of the second planetary gear set (30) is connected to the housing part (11) for conjoint rotation via a driving tooth system (35); and the lubricant feed (15) is arranged axially between the securing ring (36) and the centering (41).

23. The transmission (3) of claim 16, wherein: a first sun gear (31a) of the first planetary gear set (29) is configured for connection to an input shaft (4) for conjoint rotation; a first planet carrier (32a) of the first planetary gear set (29) is configured for at least indirect connection to a first output shaft (5) for conjoint rotation; a first ring gear (33a) of the first planetary gear set (29) is at least indirectly connected to a second sun gear (31b) of the second planetary gear set (30) for conjoint rotation; and a second ring gear (33b) of the second planetary gear set (30) is configured for at least indirectly connection to a second output shaft (6) for conjoint rotation.

24. The transmission (3) of claim 23, wherein the second ring gear (33b) of the second planetary gear set (30) is connected to a coupling shaft (38) for conjoint rotation.

25. The transmission (3) of claim 24, wherein the coupling shaft (38) is connected to a connecting shaft (39) for conjoint rotation, the connecting shaft being configured for connection to one of the first and second output shafts (5, 6) for conjoint rotation.

26. The transmission (3) of claim 25, further comprising a cover element (8) sealingly arranged spatially between the connecting shaft (39) and the housing part (11).

27. The transmission (3) of claim 16, wherein the housing part (11) accommodates a transport cover (40).

28. The transmission (3) of claim 27, wherein the transport cover (40) is at least partially made of plastic.

29. A drive train (2) for a vehicle (1), comprising: the transmission (3) of claim 16; an input shaft (4); a first output shaft (5); and a second output shaft (6), wherein the differential (7) of the transmission (3) is operatively arranged between the input shaft (4) and the first and second output shafts (5, 6), and the differential (7) is configured to distribute a drive power applied at the input shaft (4) onto the first and second output shafts (5, 6).

30. The drive train (2) of claim 29, wherein a first output torque is at least indirectly transmittable onto the first output shaft (5) by the first planetary gear set (29), a support torque of the first planetary gear set (29) is convertible in the second planetary gear set (30) such that a second output torque, which corresponds to the first output torque, is transmittable onto the second output shaft (6).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0052] An exemplary embodiment of the invention is explained in greater detail in the following with reference to the schematic drawings, in which identical or similar elements are provided with the same reference characters. Wherein:

[0053] FIG. 1 shows a highly schematized top view of an exemplary vehicle with a drive train according to example aspects of the invention and a transmission according to example aspects of the invention, according to a preferred example embodiment, and

[0054] FIG. 2 shows a highly simplified representation of the transmission according to example aspects of the invention shown in FIG. 1,

[0055] FIG. 3 shows a schematic partial sectional view of the transmission according to example aspects of the invention shown in FIG. 1 and FIG. 2, and

[0056] FIG. 4 shows a highly schematized partial sectional view of an interface between a planet carrier of a second planetary gear set and a transmission part of the transmission according to example aspects of the invention shown in FIG. 1 through FIG. 3.

DETAILED DESCRIPTION

[0057] Reference will now be made to embodiments of the invention, one or more examples of which are shown in the drawings. Each embodiment is provided by way of explanation of the invention, and not as a limitation of the invention. For example, features illustrated or described as part of one embodiment can be combined with another embodiment to yield still another embodiment. It is intended that the present invention include these and other modifications and variations to the embodiments described herein.

[0058] FIG. 1 shows a vehicle 1 with two axles 26a, 26b, wherein a drive train 2 according to the invention is drivingly arranged at the first axle 26a. The vehicle 1 is an electric vehicle in this case, the vehicle 1 being driven purely electrically. The first axle 26a can be either a front axle or a rear axle of the vehicle 1 and forms a driven axle of the vehicle 1. In this case, the drive train 2 is arranged, for example, on a non-steerable rear axle of the vehicle 1.

[0059] The drive train 2 includes a drive unit 27, which is in the form of an electric machine, and a transmission 3 which is operatively connected thereto. The design and the arrangement of the transmission 3 are explained in greater detail in the following figures. The design of the drive unit 27 is not shown here. In any case, the drive unit 27 or the electric machine has an accumulator, which supplies the drive unit 27 with electrical energy, and a power electronics system for the open-loop control and closed-loop control of the drive unit 27. A rotor (not shown here), which is arranged so as to be rotatable with respect to the stator and which is connected to an input shaft 4 (shown as an arrow in FIG. 2) for conjoint rotation, is set into rotation relative to the stator by energizing the stator (not shown here). The input shaft 4 is to be understood as a drive shaft, which transfers a drive power of the drive unit 27 into the transmission 3, the drive power being converted by a differential 7, which is in the form of an integral differential, and distributed onto a first output shaft 5 and a second output shaft 6.

[0060] The drive unit 27 is coaxial to the integral differential 7. Similarly, the output shafts 5, 6 are coaxial and, when the drive train 2 is installed, extend in opposing directions from the transmission 3 to wheels 28 on the first axle 26a. As shown in FIG. 2, joints 50 are arranged between the respective wheel 28 and the output shafts 5, 6 in order to compensate for possible inclinations of the output shafts 5, 6 with respect to wheel hubs (not shown here) on the first axle 26a.

[0061] The transmission 3 shown in FIG. 2 through FIG. 4 is a differential gear. The differential 7 has a first planetary gear set 29, which includes multiple gear set elements, and a second planetary gear set 30, which also includes multiple gear set elements and which is operatively connected to the first planetary gear set 29. A first output torque is transmittable onto the second output shaft 6 by the first planetary gear set 29. A support torque of the first planetary gear set 29 is convertible in the second planetary gear set 30 such that a second output torque, which corresponds to the first output torque, is transmittable onto the first output shaft 5.

[0062] The first planetary gear set 29 and the second planetary gear set 30 are both in the form of a negative planetary gear set and are radially nested and, therefore, arranged in a common plane, the common plane extending perpendicularly to the axle 26a. As a result, axial installation space of the transmission 3 is reduced. The first planetary gear set 29 is arranged radially inside the second planetary gear set 30 in the present case.

[0063] On the first planetary gear set 29, the first gear set element is a first sun gear 31a, the second gear set element is a first planet carrier 32a and the third gear set element is a first ring gear 33a, wherein, on the first planet carrier 32a, multiple first planet gears 34a are rotatably mounted on planet shafts (not shown here). The first planet gears 34a are meshed with the first sun gear 31a and with the first ring gear 33a.

[0064] The first output shaft 5 extends axially through the transmission 3, in particular through the integral differential 7, and through the drive unit 27. Thus the first output shaft 5 also extends axially through the first sun gear 31a of the first planetary gear set 29. Therefore, the first sun gear 31a is in the form of a gear wheel, which is hollow inside, and the input shaft 4, which is connected thereto for conjoint rotation, is in the form of a hollow shaft.

[0065] On the second planetary gear set 30, the first gear set element is a second sun gear 31b, the second gear set element is a second planet carrier 32b and the third gear set element is a second ring gear 33b, wherein, on the second planet carrier 32b, multiple first planet gears 34b are rotatably mounted on planet shafts (not shown here). The second planet gears 34b are meshed with the second sun gear 31b and with the second ring gear 33b.

[0066] The first sun gear 31a of the first planetary gear set 29 is designed to be connected to the input shaft 4 for conjoint rotation when the drive train 2 is installed. The first planet carrier 32a of the first planetary gear set 29 is designed to be connected via a spline 45 to the first output shaft 5 for conjoint rotation when the drive train 2 is installed. The first ring gear 33a of the first planetary gear set 29 is connected to the second sun gear 31b of the second planetary gear set 30 for conjoint rotation, being integrally connected thereto in this case. In addition, the second ring gear 33b of the second planetary gear set 30 is connected to a connecting shaft 39 for conjoint rotation via an annular disk-shaped coupling shaft 38, which is in the form of a ring gear carrier in this case, the connecting shaft 39 being designed to be connected to the second output shaft 6 for conjoint rotation when the drive train 2 is installed. The connecting shaft 39 is rotatably mounted on the housing part 11 via a bearing element 14.

[0067] It is explicitly pointed out that the assignment of the gear set elements to the elements of the respective planetary gear set 29, 30 can be interchanged in any way, wherein, in any case, the second planet carrier 32b is arranged on the housing part 11 in a rotationally and axially fixed manner. The connection of the gear set elements sun gear, planet carrier and ring gear is implemented according to the requirements with respect to the ratios, including signs. Instead of a negative planetary gear set, the respective planetary gear set 29, 30 can always also be in the form of a positive planetary gear set by interchanging the connection of the first planet carrier and the first ring gear and increasing the absolute value of the stationary gear ratio by one (1). This may also be correspondingly reversed. Furthermore, it is conceivable to arrange one additional gear stage between the drive unit 27 and the transmission 3, the gear stage being in the form, for example, of a spur gear stage or a planetary transmission having one or more planetary gear set(s), in order to increase an overall gear ratio of the drive.

[0068] The housing part 11 has a first lubricant feed 15 and a second lubricant feed 16, which is fluidically connected to the first lubricant feed 15. The two lubricant feeds 15, 16 can be fluidically connected to each other via a line system (not shown here), wherein coolant and/or lubricant is conveyed via the line system and the lubricant feeds 15, 16 into the interior space 49 of the transmission 3 and distributed there. The coolant and/or lubricant is referred to in the following only as lubricant for the sake of simplicity. The line system is fluidically connected to a lubricant supply (not shown here), which conveys lubricant into the system.

[0069] The first lubricant feed 15 is designed to fluidically connect the lubricant supply of the transmission 3 to an annular duct 46 as shown in FIG. 4, the annular duct 46 being formed fully circumferentially between an outer circumference 17 of a planet carrier 32b of the second planetary gear set 30 and a first inner circumference 43 of the housing part 11. In the present case, the annular duct 46 is integrated in the housing part 11 on the first inner circumference 43 of the housing part 11. The annular duct 46 is connected to a fluid chamber 48 as shown in FIG. 3 via multiple first ducts 21, which are arranged on the second planet carrier 32b extending partly radially, partly axially. The fluid chamber 48 conducts the lubricant to a planet shaft (not shown here) of the second planetary gear set 30. The annular duct 46 can be sealed (not shown here for the sake of simplicity) with respect to the rest of the transmission interior 49 by two sealing elements, which are arranged between the housing part 11 and the outer circumference 17 of the second planet carrier 32b. Lubricant for lubricating the bearings of the second planet gears 34b is therefore conducted via the first ducts 21.

[0070] The second planet carrier 32b of the second planetary gear set 30 is supported against and non-rotatably mounted on a housing part 11, which is a transmission cover in the present case. In this sense, a driving tooth system 35 for non-rotatably arranging the second planet carrier 32b on the housing part 11 is arranged in the region of the annular duct 46 between the second planet carrier 32b and the housing part 11. The driving tooth system 35 acts as a torque support of the transmission 3 and of the differential 7.

[0071] In addition, a securing ring 36 is provided in order to axially secure the second planet carrier 32b. The securing ring 36 is radially accommodated and axially positioned in a circumferential groove 44. The securing ring 36 and an axial stop 37 of the driving tooth system 35 clamp a radial projection 42 on the second planet carrier 32b between themselves, as a result of which the second planet carrier 32b cannot be axially displaced.

[0072] When the second planetary gear set 30 is installed, the second planet carrier 32b is inserted axially into the housing part 11, the planet carrier 32b being radially secured on the housing part 11 via a centering 41. In the present case, the driving tooth system 35 and the lubricant feed 15, including the annular duct 46, are arranged axially between the securing ring 36 and the centering 41.

[0073] FIG. 3 shows an assembled and transport state of the transmission 3, in which the transmission 3, in the preassembled state, has not yet been connected to the drive unit 27 or to other components of the drive train 2. The components of the transmission 3 have already been arranged inside the housing part 11 and secured in position. The housing part 11 is sealingly closed by a transport cover 40, which is made of plastic and which at least axially secures the gear set elements of the planetary gear sets 29, 30 in position. To this end, the transport cover 40 can have axial projections 47 which abut the gear set elements which are to be axially secured. In FIG. 3, such an exemplary axial projection 47 axially abuts the first planet carrier 32a of the first planetary gear set 29. The transport cover 40 is detachably connected to the housing part 11 so that the transport cover 40 can be removed when the drive unit 27 is to be connected, with the input shaft 4, to the transmission 3 in order to install the drive train 2. In this sense, the housing part 11 has means for accommodating a transport cover 40.

[0074] On an opposite side of the housing part 11, a cover element 8, with which the transmission interior 49 is sealingly closed, is arranged spatially between the connecting shaft 39 and the housing part 11. The second lubricant feed 16 is designed to conduct lubricant to the cover element 8. As shown in FIG. 3, the cover element 8 has multiple second ducts 9, which are uniformly distributed over the circumference and which extend essentially radially. Lubricant is conveyed via the respective second duct 9 radially from the outside, i.e., from the second lubricant feed 16, radially inward to the connecting shaft 39, from where the lubricant is distributed in the transmission 3, in particularly for lubricating the output shafts 5, 6, the corresponding bearing points, and the gear set elements of the first planetary gear set 29. The components of the transmission 3, in particular the gear set elements of the differential 7, connecting points and shafts, and bearing points are lubricated and cooled via the lubricant feeds 15, 16 (shown here). Further lubricant feeds (not shown here) are also conceivable.

[0075] A slip ring 10 is arranged spatially between the cover element 8 and the connecting shaft 39. When the cover element 8 is installed, the slip ring 10 is arranged radially between an inner circumference 12 of the cover element 8 and an outer circumference 13 of the second connecting shaft 39 and reduces friction between the housing-fixed cover element 8 and the connecting shaft 39, which is mounted for rotation with respect to the cover element 8. Furthermore, sealing elements 18 in the form of rectangular rings are arranged between the slip ring 10 and the connecting shaft 39, the sealing elements 18 being designed to emit a defined amount of leakage between the slip ring 10 and the connecting shaft 39 into the transmission interior 49.

[0076] The slip ring 10 has a number of passage openings corresponding to the second ducts 9. One passage opening aligns with a third duct 22 in each case, the third duct 22 being in the form of a transversal bore in the connecting shaft 39. Furthermore, a radial shaft seal 24 is sealingly arranged radially between the cover element 8 and the second output shaft 6 in order to seal the transmission interior 49 with respect to the external atmosphere of the transmission 3. The cover element 8 has at least one essentially radially extending discharge bore 23, which is designed to return lubricant from radially inside to radially outside.

[0077] Further sealing elements 19 are arranged radially between an outer circumference 20 of the cover element 8 and a second inner circumference 25 of the housing part 11. The sealing elements 19 are axially spaced apart from one another on the cover element 8. Two of the sealing elements 19 are provided for sealing the second duct 9 in the cover element 8. One of these sealing elements 19 and another sealing element 19 are provided for sealing the discharge bore 23. The sealing element 19 situated in the center in an axial direction therefore fluidically separates the second duct 9 from the discharge bore 23.

[0078] The cover element 8 is a cover for bridging a change of diameter between the bearing element 14 and the radial shaft seal 24. The cover element 8 is in the form of a seat for the radial shaft seal 24. Lubricant is transferred from radially outside toward radially inside via the cover element 8 without additional lines or ducts. The cover element 8 also enables lubricant to drain from radially inside toward radially outside via the respective discharge bore 23. In addition, the cover element 8 is designed or equipped with seals 18, 19 such that the second and third ducts 9, 22 and the respective discharge bore 23 are sealed.

[0079] Modifications and variations can be made to the embodiments illustrated or described herein without departing from the scope and spirit of the invention as set forth in the appended claims. In the claims, reference characters corresponding to elements recited in the detailed description and the drawings may be recited. Such reference characters are enclosed within parentheses and are provided as an aid for reference to example embodiments described in the detailed description and the drawings. Such reference characters are provided for convenience only and have no effect on the scope of the claims. In particular, such reference characters are not intended to limit the claims to the particular example embodiments described in the detailed description and the drawings.

REFERENCE CHARACTERS

[0080] 1 vehicle [0081] 2 drive train [0082] 3 transmission [0083] 4 input shaft [0084] 5 first output shaft [0085] 6 second output shaft [0086] 7 differential [0087] 8 cover element [0088] 9 second duct [0089] 10 slip ring [0090] 11 housing part [0091] 12 inner circumference of the cover element [0092] 13 outer circumference of the connecting shaft [0093] 14 bearing element [0094] 15 first lubricant feed [0095] 16 second lubricant feed [0096] 17 outer circumference of the second planet carrier of the second planetary gear set [0097] 18 first sealing element [0098] 19 second sealing element [0099] 20 outer circumference of the cover element [0100] 21 first duct [0101] 22 third duct [0102] 23 discharge bore [0103] 24 radial shaft seal [0104] 25 second inner circumference of the housing part [0105] 26a first axle [0106] 26b second axle [0107] 27 drive unit [0108] 28 wheel [0109] 29 first planetary gear set [0110] 30 second planetary gear set [0111] 31a first sun gear of the first planetary gear set [0112] 31b second sun gear of the second planetary gear set [0113] 32a first planet carrier of the first planetary gear set [0114] 32b second planet carrier of the second planetary gear set [0115] 33a first ring gear of the first planetary gear set [0116] 33b second ring gear of the second planetary gear set [0117] 34a first planet gear of the first planetary gear set [0118] 34b second planet gear of the second planetary gear set [0119] 35 driving tooth system [0120] 36 securing ring [0121] 37 axial stop on the housing part [0122] 38 coupling shaft [0123] 39 connecting shaft [0124] 40 transport cover [0125] 41 centering [0126] 42 radial projection on the planet carrier of the second planetary gear set [0127] 43 first inner circumference of the housing part [0128] 44 groove in the housing part [0129] 45 spline [0130] 46 annular duct [0131] 47 axial projection [0132] 48 fluid chamber [0133] 49 transmission interior [0134] 50 joint