Transmission for a vehicle

Abstract

Transmission (10) for a vehicle, comprising an input shaft (11), an output shaft (12), at least two planetary gear sets arranged coaxially to the input shaft (11), namely at least a first planetary gear set (20) and at least a second planetary gear set (30) each with a sun gear (21, 31), a planet carrier (22, 32) and a ring gear (23, 33), and comprising a first and second brake (2, 3), wherein the input shaft (11) is non-rotatably connected to a first sun gear (21) and a second sun gear (31) of the first and second planet gear set (20, 30), respectively, and the output shaft (12) is non-rotatably connected to a first planet carrier (22) and a second planet carrier (32) of the first and second planet gear set (20, 30), respectively. the first brake (2) is designed to fix a first ring gear (23) of the first planetary gear set to a rotationally fixed component (0), and the second brake (3) is designed to fix a second ring gear (33) of the second planet gear set to the rotationally fixed component (0), wherein the first planet carrier (22) has a plurality of first planet gears (24) mounted on respective first bolts (25), and the second planet carrier (32) has a plurality of second planet gears (34) mounted on respective second bolts (35), characterized in that the first and second planet gears (24, 34) each have a bearing base (26, 36) which is wider than the toothing of the respective first and second planet gears (24, 34), wherein the majority of first planet gears (24) have a respective bearing base (26) which extends at least partially axially from the axial plane of the first planet gear set (20) into the axial plane of the second planet gear set (30) and / or the majority of second planet gears (34) have a respective bearing base (36) which extends at least partially axially from the axial plane of the second planet gear set (30) into the axial plane of the first planet gear set (20).

Description

[0001] The invention relates to a gearbox, an electric drive and a vehicle with such a gearbox or such an electric drive.

[0002] German patent DE 10 2011 007 455 A1 discloses an axle drive for a motor vehicle comprising a differential connected to a two-speed transmission with reversing direction. The two-speed transmission is arranged in the power flow between the differential and a drive unit and has one or more planetary gear stages. The differential is designed as a spur gear differential in a planetary configuration, wherein at least one set of differential gears and at least one set of planet gears of at least one planetary gear stage are arranged on the same or approximately the same pitch circle diameter. Such a transmission is also disclosed in US patent US 10 955 030 B2.

[0003] The object of the present invention is to provide an alternative transmission for a vehicle, an electric drive with such a transmission, and a vehicle with such a transmission or electric drive. In particular, a multi-speed transmission is to be provided that enables the connection of a high-speed electric motor and at the same time has a compact axial design.

[0004] The problem is solved by the features of the independent claims. Preferred embodiments are described in the dependent claims.

[0005] The transmission therefore assumes a transmission for a vehicle, comprising an input shaft, an output shaft, at least two planetary gear sets arranged coaxially to the input shaft, namely a first and a second planetary gear set, each with a sun gear, planet carrier and a ring gear, as well as a first and second brake.

[0006] The input shaft is non-rotatably connected to the first and second sun gears of the first and second planetary gear sets, respectively. The output shaft is non-rotatably connected to the first and second planet carriers of the first and second planetary gear sets, respectively. The first brake is designed to lock the first ring gear of the first planetary gear set to a non-rotatable component, while the second brake is designed to lock the second ring gear of the second planetary gear set to the same non-rotatable component. The brakes can be either positive-locking or friction-locking. The output shaft of the transmission can be arranged coaxially or parallel to the first and second planetary gear sets.

[0007] The planetary gear sets are designed in particular as so-called negative planetary gear sets and are preferably arranged axially side by side. A negative planetary gear set is composed, in a manner known in principle to those skilled in the art, of the elements sun gear, planet carrier and ring gear, wherein the planet carrier rotatably carries at least one, but preferably several, planet gears, each of which meshes with both the sun gear and the surrounding ring gear, i.e., is in tooth mesh.

[0008] The transmission described above, which can also be called a 2-stem 4-shaft transmission, allows two forward gears, whereby closing the first shifting element results in a first gear and closing the second shifting element results in a second gear.

[0009] It has been found that the gearbox with this connection of the planetary gear sets is very easy to manufacture. In particular, two negative planetary gear sets, which are known from the prior art, can be used. By using brakes instead of clutches, the gearbox can be built particularly compactly.

[0010] Furthermore, the gearbox is extremely robust at varying speeds. This allows for very low ring gear and planetary gear speeds, while the sun gears can operate at very high speeds. Low ring gear speeds reduce drag torque and wobble. Low planetary gear speeds reduce bearing losses and have a positive effect on acoustics.

[0011] It has also been shown that both planet carriers can be mounted on a single bearing. A single bearing is particularly feasible because the differential rotational speeds at the planet gears are small.

[0012] For the purposes of this invention, a "shaft" is understood to be a rotatable component of the transmission by which the respective transmission components are connected to each other in a rotationally fixed manner, or by which such a connection is established upon actuation of a corresponding switching element. The shaft can connect the components axially or radially, or both axially and radially. The shaft can also act as an intermediate piece, for example, by connecting a component radially. The term "shaft" does not preclude the possibility that the components to be connected may be manufactured as a single unit. For transmission components that are only connected to each other in a rotationally fixed manner by actuation of a respective switching element, the connection is also preferably achieved via one or more intermediate shafts.

[0013] In the context of the invention, "axial" refers to an orientation along a longitudinal center axis, along which the planetary gear sets are arranged coaxially to one another. "Radial" refers to an orientation in the diameter direction of a shaft that lies on this longitudinal center axis.

[0014] The rotationally fixed component of the transmission can preferably be a permanently stationary component, more preferably a transmission housing, a part of such a housing, or a component rigidly connected to it. If an element of a transmission component, such as an element of a planetary gear set, is permanently or temporarily fixed to a rotationally fixed component by means of a switching element, it is permanently or temporarily prevented from rotating.

[0015] In this transmission, the first sun gear preferably has a smaller effective diameter than the second sun gear. The planet gears of the first planetary gear set preferably have a larger effective diameter than the planet gears of the second planetary gear set. Accordingly, the ring gear of the first planetary gear set preferably has a smaller effective diameter than the ring gear of the second planetary gear set. Such a transmission exhibits good gear efficiency and is also extremely compact.

[0016] According to the invention, the first planet carrier has a plurality of first planet gears mounted on respective first bolts, and the second planet carrier has a plurality of second planet gears mounted on respective second bolts. The planet carriers thus each comprise several bolts for receiving their planet gears.

[0017] Unlike a gearbox where the planet gears of the first and second planet gear sets are mounted on a common bolt, providing separate bolts for each allows for greater variability in the gearbox design.

[0018] For example, the number of planet gears in the first planet gear set can differ from the number of planet gears in the second planet gear set. For instance, the first planet gear set might have four planet gears and the second planet gear set three, or vice versa.

[0019] Alternatively, the number of planet gears in the first planet gear set and the number of planet gears in the second planet gear set can be identical. If the number is identical, it is preferred that the first and second planet gear sets each have exactly three or four planets, respectively.

[0020] Furthermore, the bolt circle diameter of the first planet carrier and the bolt circle diameter of the second planet carrier can be different. Alternatively, the bolt circle diameter of the first planet carrier and the bolt circle diameter of the second planet carrier can be identical. Different bolt circle diameters allow for better adjustment of the stationary gear ratio. In particular, by changing the bolt circle diameter of the second planet carrier, the second planet gears can be brought "closer" to the second sun gear of the second planet gear set.

[0021] Preferably, the first brake is arranged in the same axial plane as the first planetary gear set, and the second brake is arranged in the same axial plane as the second planetary gear set. It has been found that two switching elements designed as brakes can be arranged radially very efficiently between the ring gears and the gearbox housing, thus enabling the construction of an extremely axially compact gearbox.

[0022] In order to enable a load-shiftable shift from first to second gear, it is preferred if the first brake is positively locking, e.g. as a claw, and the second brake is frictionally locking.

[0023] The planet carriers of the first and second planet gear sets can be connected to each other in a rotationally fixed manner with or without a so-called central web.

[0024] In a preferred embodiment, the central web is omitted to save axial length. In an arrangement without a central web, the webs of the first and second planet carriers run at least partially parallel to each other. In particular, the two webs extend axially into the respective axial plane of the other planetary gear set. It is advantageous to join the bolts of both planet carriers at a single end face and to mount both planet carriers on only one bearing. Such a bearing can, in particular, be arranged on an end face of one of the planetary gear sets facing away from the other.

[0025] Such an arrangement is not only particularly compact axially, but also allows for a wide bearing base for each planetary gear. While a wide bearing base can also be used in an arrangement with a central web, the advantage of axial compactness is particularly evident in an arrangement without a central web.

[0026] According to the invention, particularly in an arrangement of the planet carriers without a central web, the majority of first planet gears have a respective bearing base which extends axially from the axial plane of the first planet gear set into the axial plane of the second planet gear set; and according to the invention, the majority of second planet gears have a respective bearing base which extends axially from the axial plane of the second planet gear set into the axial plane of the first planet gear set.

[0027] The effect of a so-called wide bearing base lies primarily in reducing the tilting of the planetary gear. This prevents, in particular, "edge running," where the bearing roller carries the planetary gear on its edges. Overall, a wide bearing base allows for better distribution of bearing forces. Furthermore, it offers acoustic advantages, as the wide bearing base also results in smooth running. Each of these effects, as well as the sum of them, is achieved without compromising installation space, since the width of the bearing base coincides with the width of both planetary gear sets.

[0028] The arrangement of the planet carriers described above, i.e. without a central web, causes each planet gear set to have the same number of planet gears, since the axially parallel bolts of the first and second planet carriers, viewed in cross-section, are arranged alternately in a circumferential direction.

[0029] As an alternative to the embodiment described above, a central web is provided which connects the first and second planet carriers in a rotationally fixed manner.

[0030] Preferably, the central web is formed by two separate, rotationally fixed individual webs of the first and second planet carriers.

[0031] Alternatively, the central web can be formed by designing the first and second planet carriers as an integral planet carrier, which is arranged axially between the first and second planet gear sets. This allows the first and second bolts to be supported in the central web from the left and right, respectively.

[0032] It is possible to provide a transmission with more than two gears, in particular with three gears. It is preferred that a third planetary gear set and a third shift element are provided, wherein a third sun gear of the third planetary gear set is non-rotatably connected to the input shaft, and the third brake is designed to lock a third ring gear to the non-rotatable component. A third gear can be generated by engaging the third brake. In other words, a third planetary gear set is arranged in a manner analogous to the first two planetary gear sets. The third planetary gear set is preferably designed as a negative planetary gear set.

[0033] In a further embodiment of the invention, a differential device connected to the output shaft is provided. It is customary to reduce the rotational speed of the output shaft before it is introduced into the differential device. For the initial reduction, it is advantageous to provide a transmission, for example in the form of a spur gear stage or a planetary gear set. It should be noted that the differential device can be used with both a 2-speed and a 3-speed version of the transmission.

[0034] Preferably, the output shaft of the transmission has teeth via which it is operatively connected to a differential device arranged axially parallel to the output shaft in the vehicle drivetrain. In this case, the operative connection can be provided by means of a spur gear stage, wherein a first spur gear forms the teeth of the output shaft or is rotationally fixed to the output shaft, while a second spur gear of the spur gear stage, preferably an input element of the differential device, is correspondingly in mesh with the output shaft.

[0035] Alternatively, instead of a spur gear stage, an additional planetary gear set may be provided. It is therefore preferred if at least a fourth planetary gear set is provided, comprising a fourth sun gear, a fourth planet carrier, and a fourth ring gear. A first element from the group consisting of a fourth sun gear, a fourth planet carrier, and a fourth ring gear is non-rotatably connected to the output shaft. A second element from the group consisting of a fourth sun gear, a fourth planet carrier, and a fourth ring gear is non-rotatably connected to an input element of the differential assembly. A third element from the group consisting of a fourth sun gear, a fourth planet carrier, and a fourth ring gear is permanently fixed to the non-rotatably connected component.

[0036] Three advantageous connections of the at least fourth planetary gear set to the differential assembly are possible: The first element can be the sun gear, the second the planet carrier, and the third the ring gear. Alternatively, the first element can be the ring gear, the second the planet carrier, and the third the sun gear. Another alternative connection is the first element can be the sun gear, the second the ring gear, and the third the planet carrier. Each of these three solutions provides a different gear ratio for the vehicle's output shafts.

[0037] The spur gear solution offers the advantage of providing a gearbox with a differential that is particularly compact axially. In contrast, the planetary gear set solution offers the advantage of providing a gearbox with a differential that is particularly compact radially.

[0038] If at least a fourth planetary gear set is provided as a transmission gear, it is further preferred if one of the two output shafts of the differential device is passed through the hollow sun gears of the first and second planetary gear sets and through the hollow input shaft.

[0039] Furthermore, a fourth switching element can be provided, which is configured to connect an input element of the differential device to an output element of the differential device in a rotationally fixed manner. The fourth switching element, which is preferably a coupling, acts as a differential lock.

[0040] A second aspect involves the provision of an electric drive. This electric drive comprises a gearbox as described above and an electric motor connected to the gearbox's input shaft. The electric motor's rotor can be fixed to the input shaft or connected to it via a reduction gear. The electric motor is arranged coaxially or parallel to the input shaft.

[0041] According to a third aspect of the invention, a vehicle is provided with a transmission or electric drive described above.

[0042] In the context of the invention, the fact that two components of the transmission are rotationally fixed, "connected," or "coupled" means a permanent coupling of these components, preventing them from rotating independently. Specifically, no switching element is provided between these components, which may be elements of the planetary gear sets and / or shafts and / or a rotationally fixed component of the transmission; instead, the corresponding components are rigidly coupled to one another. A torsionally flexible connection between two components is also considered rigid or rotationally fixed. In particular, a rotationally fixed connection may also include joints, for example, to enable steering movement or suspension travel of a wheel.

[0043] Advantageous embodiments of the invention, which are explained below, are illustrated in the drawings. They show: Fig. 1 a schematic view of a vehicle powertrain with an electric drive according to a first embodiment; Fig. 2 an electric drive with a gearbox in a preferred embodiment in a schematic view; Fig. 3 a section of the gearbox from Fig. 2 in one cut; Fig. 4 an electric drive with a gearbox in a further preferred embodiment in a schematic view; Fig. 5 an electric drive with a gearbox in a further preferred embodiment in a schematic view; Fig. 6 the electric drive with a gearbox in a further preferred embodiment in a schematic view; Fig. 7 an electric drive with a gearbox in a further preferred embodiment in a schematic view; Fig. 8 different connection options for a drive constant in a schematic view; and Fig. 9 an electric drive in a further preferred embodiment in a schematic view.

[0044] Fig. Figure 1 shows a schematic view of a motor vehicle drivetrain of a vehicle 100 according to a first embodiment, wherein an electric motor 7 is connected to a transmission 10 in the motor vehicle drivetrain, both arranged coaxially to an axle A. The transmission 10 and the electric motor 7 form an electric drive 1. A differential 60 is connected downstream of the transmission 10 on the output side, via which drive power is distributed to drive wheels 105 of a drive axle B of the vehicle, wherein a planetary gear set for pre-reduction of the output speed is arranged between the transmission 10 and the differential 60. The electric drive 1 is designed as an axle-parallel 2-speed electric drive and is oriented transversely to one direction of travel of the vehicle 100.

[0045] Fig. Figure 2 shows an electric drive 1 as it is used in a vehicle according to Fig. 1 can be used, comprising a gearbox 10 in a preferred embodiment and an electric machine 7 connected to the gearbox. The electric machine has a rotor 7.1 and a stator 7.2 fixed to a rotationally fixed component 0.

[0046] The gearbox comprises an input shaft 11 connected to the rotor 7.1, an output shaft 12, a first planetary gear set 20, a second planetary gear set 30 arranged coaxially to the first planetary gear set, a first brake 2 and a second brake 3. The output shaft 12 is arranged coaxially to the input shaft 11 and to the planetary gear sets 20 and 30.

[0047] The first and second planet gear sets 20, 30 are each designed as a negative planet gear set, each with a ring gear, a planet carrier, and a sun gear. Both planet gear sets have a plurality of planet gears 24, 34, wherein, according to this embodiment, each planet gear set 20, 30 has a first group of exactly three planet gears 24 and a second group of exactly three planet gears 34, respectively.

[0048] A first sun gear 21 of the first planetary gear set 20 is non-rotatably connected to a second sun gear 31 of the second planetary gear set 30, with both sun gears 21, 31 being non-rotatably connected to the input shaft 11. In other words, the gearbox 10 has a double sun gear which is non-rotatably connected to the input shaft 11.

[0049] A first planet carrier 22 of the first planet gear set 20 and a second planet carrier 32 of the second planet gear set 30 are non-rotatably connected to the output shaft 12. In other words, the planet carriers 22 and 32 form the output shaft 12 of the transmission. It is clearly visible that the sun gear 21 has a smaller effective diameter than the sun gear 31. Accordingly, the three planet gears 24 each have a larger effective diameter than the three planet gears 34.

[0050] The first brake 2 is designed to lock a first ring gear 23 of the first planetary gear set 20 to a rotationally fixed component 0, wherein the rotationally fixed component 0 is, in this case, the gearbox housing of the gearbox 10. The second switching element 3 is designed to lock a second ring gear 33 of the second planetary gear set 30 to the rotationally fixed component 0. Both switching elements are designed as friction switching brakes.

[0051] As can be clearly seen, the first brake 2 is arranged radially between the first planetary gear set 20 and the housing 0, while the second brake 3 is arranged radially between the second planetary gear set 30 and the housing 0. Thus, the first brake 2 is arranged in an axial plane with the first planetary gear set 20, and the second brake 3 is arranged in an axial plane with the second planetary gear set 30.

[0052] By selectively applying brakes 2 and 3, two forward gears can be represented, whereby one of the two brakes must be applied while the other is open to form the gears. Applying the first brake 2 represents a first gear, and applying the second brake 3 represents a second gear.

[0053] The output shaft 12 of the transmission 10 further comprises a toothed section through which the output shaft 12 is operatively connected to a differential device 60 arranged axially parallel to the output shaft 12, which is designed as a bevel gear differential. According to this example, the operative connection is provided by means of a spur gear stage, wherein a first spur gear 64 forms the toothed section of the output shaft 12, while a second spur gear 61 meshes with the output shaft 12 in accordance with the spur gear stage. The second spur gear 61 simultaneously forms the input element of the differential.

[0054] The bevel gear differential 60 further comprises, in a manner known per se, two output elements 62, 63, each of which is connected to a drive shaft of the vehicle.

[0055] The translation I diff The differential 60 is, according to this embodiment, I diffequal to 2.0. According to this embodiment, the stationary gear ratio I0 for the first planetary gear set is equal to -4.0 and for the second planetary gear set is equal to I0 -2.0.

[0056] The in Fig. The electric drive shown in Figure 2 is a 2-speed drive with an axially parallel design. This drive is very compact, especially axially compact, and enables, among other things, a closed hydraulic system. Furthermore, only a single planetary carrier is required.

[0057] The first and second planetary carriers 22 and 32, respectively, are connected to each other without a central bridge. A preferred embodiment of a bridge-less connection is described in section [reference to be added]. Fig. 3 can be seen.

[0058] Fig. Figure 3 shows on the left a section D of the electric drive 1 from Fig. 2 in a side section to better illustrate the rotationally fixed connection of the first and second planet gear set 20, 30 and the bearing of the planet gears 24 and 34 respectively. Fig. Figure 3 on the right shows a cross-section not to scale in a schematic view.

[0059] The first planet carrier 22 has three first planet gears 24 mounted on first bolts 25. The second planet carrier 32 also has three second planet gears 34 mounted on second bolts 35. The three first and three second bolts 25, 35 are arranged alternately in the same axial plane and circumferentially.

[0060] The first and second planet carriers 20 and 30, respectively, are mounted on a single bearing 45 in the gearbox. The bearing 45, which is a cylindrical roller bearing, is located axially between the toothing 64 and the first planet gear set 20 on an end face of the first planet gear set 20 facing away from the planet gear set 30. The six bolts 25, 35 are inserted into the respective planet gears from this side (from the left).

[0061] According to the invention, the first and second planet gears 24 and 34 each have a bearing base 26 and 36, respectively, which is wider than the teeth of the respective first and second planet gears 24 and 34. The bearing base 26 extends 27 from the axial plane of the first planet gear set (20) at least partially axially into the axial plane of the second planet gear set (30). The bearing base 36 extends 37 from the axial plane of the second planet gear set at least partially axially into the axial plane of the first planet gear set. The respective bearing base 26 of the first planet gears 24 has approximately the same axial extent as the respective bearing base 36 of the second planet gears 34. According to this embodiment, the respective bearing base is approximately twice as wide as the respective teeth.It can be clearly seen that the width of the bearing base 27 of the respective first planet gears 24 and the width of the bearing base 37 of the respective second planet gears 34 essentially correspond to the width of the first and second planet gear set.

[0062] Furthermore, it can be clearly seen in the right-hand image that the first and second bolts 25, 35 have the same pitch circle diameter and are arranged alternately in the circumferential direction.

[0063] Fig. Figure 3 further shows that the two brakes 2, 3 are arranged radially between the housing 0 and the respective ring gears 23, 33 in order to provide a particularly compact axial gearbox or electric drive.

[0064] Fig. Figure 4 shows the axle-parallel electric drive. Fig. 2 and 3 respectively, the difference being that the connection between the first and second planet gear sets is effected by means of a central web 40. The central web 40 connects the two planet carriers 22, 32 to each other in a rotationally fixed manner and is arranged axially between the first and the second planet gear sets 20, 30.

[0065] The central web 40 changes the stationary gear ratio. Thus, the bolt circle diameter of the second bolts is smaller than in the embodiment according to [reference]. Fig. 2 or 3, which brings the second planet gears 35 particularly "closer" to the second sun gear 31. In addition, the number of second planet gears 35 was increased from three to four.

[0066] Fig. 5 shows the electric drive 1 from Fig. 4, wherein, in contrast, a differential lock 9 is provided in the form of a clutch. In the actuated state, the clutch 9 connects the input element 61 with the second output element 63 of the differential 60 in a rotationally fixed manner.

[0067] Fig. 6 shows the gearbox. Fig. 2, in contrast, the speed transmission of the output shaft 12 is effected not by a spur gear stage 64 / 61 but by a fourth planetary gear set 70 to provide a coaxial electric drive. The parking lock gear 8 is positioned axially between the second and fourth planetary gears 70.

[0068] The fourth planetary gear set 70 comprises a fourth sun gear 71, a fourth planet carrier 72, and a fourth ring gear 73. A first element from the group consisting of the fourth sun gear, fourth planet carrier, and fourth ring gear, in this case the sun gear 71, is non-rotatably connected to the output shaft 12. A second element from the group consisting of the fourth sun gear, fourth planet carrier, and fourth ring gear, in this case the planet carrier 72, is non-rotatably connected to an input element 61 of the differential assembly 60. A third element from the group consisting of the fourth sun gear, fourth planet carrier, and fourth ring gear, in this case the ring gear 73, is permanently fixed to the non-rotatable component 0. The first output element 62 of the differential 60 passes through the input shaft 11, which is designed as a hollow shaft. In the actuated state, the clutch 9 connects the input element 61, which is connected to the planet carrier 72, to the output element 63 of the differential 60.

[0069] The connection of the first and second planetary gear sets 20 and 30 respectively is realized by means of a center-less connection, as shown in Fig. 3 explained in more detail. The connection of the fourth planetary gear set 70 with the second planetary gear set 30 can, for example, be made via a central bridge.

[0070] The in Fig. The electric drive shown in Figure 6 is a 2-speed drive in a coaxial design. This drive is very compact, especially radially compact, and enables, among other things, a closed hydraulic system.

[0071] Fig. Figure 7 shows the electric drive 1 from Fig. 6, in contrast to the one from Fig. 4 known central webs 40 are used to connect the first and second planet gear sets 20, 30.

[0072] Fig. 6 and Fig. Figure 7 shows the so-called output constant in a first embodiment. However, the output constant can also be applied to the gearbox 10 in a different way. Fig. 6 and Fig. 7 will be connected. Fig. Figure 8 shows two additional variants. On the left is the fourth planetary gear set 70 in the first connection variant described above.

[0073] In the center, a second connection variant of the fourth planetary gear set 70 is shown, in which, unlike the first variant, the connection of the sun gear and ring gear is reversed. Accordingly, a first element from the group fourth sun gear, fourth planet carrier, and fourth ring gear, in this case ring gear 73, is rotationally fixed to the output shaft 12. A second element from the group fourth sun gear, fourth planet carrier, and fourth ring gear, in this case planet carrier 72, is rotationally fixed to an input element 61 of the differential assembly 60. A third element from the group fourth sun gear, fourth planet carrier, and fourth ring gear, in this case sun gear 71, is permanently fixed to the rotationally fixed component 0.

[0074] On the right, a third connection variant of the fourth planetary gear set 70 is shown, in which, unlike the first variant, the connection of the planet carrier and ring gear is reversed. Accordingly, a first element from the group consisting of the fourth sun gear, fourth planet carrier, and fourth ring gear, in this case the sun gear 71, is rotationally fixed to the output shaft 12. A second element from the group consisting of the fourth sun gear, fourth planet carrier, and fourth ring gear, in this case the ring gear 73, is rotationally fixed to an input element 61 of the differential assembly 60. A third element from the group consisting of the fourth sun gear, fourth planet carrier, and fourth ring gear, in this case the planet carrier 72, is permanently fixed to the rotationally fixed component 0.

[0075] Fig. 9 shows the electric drive 1 off Fig. 4 in a 3-speed version. In contrast to the embodiment according to. Fig.2 the transmission 10 has a third planetary gear set 50 and a third switching element 5.

[0076] The third planetary gear set 50 is also designed as a negative planetary gear set and comprises a third sun gear 51, which is non-rotatably connected to the input shaft 11. It further comprises a third planet carrier 52, which is non-rotatably connected to the output shaft 12. The third switching element 5 is designed to fix a third ring gear 53 to the non-rotatable component 0.

[0077] The third planet carrier 52 has three third planet gears 54. The third planet carrier 52 is rotationally fixed to the second planet carrier 32 by means of a central web 41. The transmission ratio I diffThe differential ratio 60 is 2.0 according to this embodiment. The stationary gear ratio I0 is -4.0 for the first planetary gear set, -3.0 for the second planetary gear set, and -2.0 for the third planetary gear set, according to this example.

[0078] To illustrate the third gear, the third shifting element 5, which is a friction shift brake, is actuated, while the first and second shifting elements 2, 3 are open.

[0079] By adding another planetary gear set and another brake, connected as described above, an electric drive with three forward gears can be provided. In principle, this seriesing of "simple" negative planetary gear sets could be continued for further forward gears. Reference sign 1 Electric drive 2 switching element 3 switching element 5 switching element 7 Electric machine 7.1 7.2 Rotor Stator 8 Parking restrictions 9 Switching element, clutch 10 gearboxes 11 Input wave 12 Output shaft 20 first planetary gear set 21 first sun wheel 22 first planetary carrier 23 first ring gear 24 first planetary gear 30 second planetary gear set 31 second sun wheel 32 second planetary carrier 33 second ring gear 34 second planetary gear 40 Middle walkway 41 Middle walkway 50 third planetary gear set 51 third sun wheel 52 third planetary carrier 53 third ring gear 60 Differential device, bevel gear differential 61 Input element, gearing, second gear of the spur gear stage 62 Output element 63 Starting element 64 teeth, first gear of the spur gear stage 70 fourth planetary gear set 71 fourth sun wheel 72 fourth planetary carrier 73 fourth ring gear 100 vehicles An electric drive axle B Vehicle drive axle D neckline

Claims

[1] Transmission (10) for a vehicle, comprising an input shaft (11), an output shaft (12), at least two planetary gear sets arranged coaxially to the input shaft (11), namely at least a first planetary gear set (20) and at least a second planetary gear set (30) each with a sun gear (21, 31), a planet carrier (22, 32) and a ring gear (23, 33), and comprising a first and second brake (2, 3), wherein the input shaft (11) is non-rotatably connected to a first sun gear (21) and a second sun gear (31) of the first and second planet gear set (20, 30), respectively, and the output shaft (12) is non-rotatably connected to a first planet carrier (22) and a second planet carrier (32) of the first and second planet gear set (20, 30), respectively. the first brake (2) is designed to fix a first ring gear (23) of the first planetary gear set to a rotationally fixed component (0), and the second brake (3) is designed to fix a second ring gear (33) of the second planet gear set to the rotationally fixed component (0), wherein the first planet carrier (22) has a plurality of first planet gears (24) mounted on respective first bolts (25), and the second planet carrier (32) has a plurality of second planet gears (34) mounted on respective second bolts (35), characterized by , that the first and second planet gears (24, 34) each have a bearing base (26, 36) which is wider than the toothing of the respective first and second planet gears (24, 34), wherein the majority of first planet gears (24) have a respective bearing base (26) which extends at least partially axially from the axial plane of the first planet gear set (20) into the axial plane of the second planet gear set (30) and / or the majority of second planet gears (34) have a respective bearing base (36) which extends at least partially axially from the axial plane of the second planet gear set (30) into the axial plane of the first planet gear set (20). [2] Transmission according to claim 1, wherein the output shaft (12) is arranged coaxially or parallel to the first and second planet gear set (20, 30). [3] Transmission according to one of the preceding claims, wherein at least one of the brakes (2, 3) is designed to be positively engaged. [4] Transmission according to one of the preceding claims, wherein at least one of the brakes (2, 3) is designed to be frictionally engaged. [5] Transmission according to one of the preceding claims, wherein the first brake (2) is arranged in an axial plane with the first planetary gear set (20), and the second brake (3) is arranged in an axial plane with the second planetary gear set (30). [6] Gearbox according to any of the preceding claims, wherein the width (27) of the bearing base (26) of the respective first planet gears (24) and / or the width (37) of the bearing base (26) of the respective second planet gears (34) corresponds to the width of the first and second planet gear set (20, 30). [7] Gearbox according to one of the preceding claims, wherein the first and second planet carriers (22, 32) are connected to each other by means of a central web (40). [8] Transmission according to one of the preceding claims, wherein a differential device (60) is provided which is connected to the output shaft (12) via a transmission transmission. [9] Transmission according to claim 8, wherein the transmission transmission is designed as a spur gear stage, wherein a first spur gear (64) of the spur gear stage is non-rotatably connected to the output shaft (12) and a second spur gear (61) of the spur gear stage forms the input element of the differential device (60). [10] Transmission according to claim 8, wherein the transmission transmission is designed as an at least third planetary gear set (70) with a third sun gear (71), a third planet carrier (72) and a third ring gear (73), wherein a first element from the group third sun gear, third planet carrier and third ring gear is rotationally fixed to the output shaft (12), a second element from the group third sun gear, third planet carrier and third ring gear is rotationally fixed to an input element (61) of the differential device (60), and a third element from the group third sun gear, third planet carrier and third ring gear is permanently fixed to the rotationally fixed component (0). [11] Transmission according to one of claims 8 to 10, wherein a fourth switching element (6) is provided which is designed to connect an input element (61) of the differential device (60) to an output element (62, 63) of the differential device in a rotationally fixed manner. [12] Electric drive with a gearbox according to one of the preceding claims, wherein the input shaft (11) is connected to a rotor (2.1) of an electric machine (2). [13] Vehicle with a transmission according to any one of claims 1 to 11 or an electric drive according to claim 12.

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