Transmission assembly and drive train having such transmission assembly

Abstract

The invention relates to a transmission arrangement and a drive train having such a transmission arrangement, comprising a planetary gear set having a planet carrier on which at least one pin is arranged, a first bearing element for rotatably supporting a planet gear being arranged on the pin, a second bearing element being arranged on the first bearing element for rotatably supporting the planet gear, and a third bearing element being arranged on the second bearing element for rotatably supporting the planet gear. The transmission assembly further comprises a differential which is drivingly connected to the planet carrier and which transmits the drive power acting on the planet carrier to the first central shaft and to a second central shaft which is arranged coaxially to the first central shaft, at least the first central shaft has a central first channel for supplying coolant and / or lubricant to the interior of the differential, and wherein at least one first bore extending radially at least in sections is formed on the planet carrier in order to guide coolant and / or lubricant from the interior of the differential into a second channel of the bolt.

Description

Field of the Invention

[0001] The present invention relates to a transmission assembly for a drive train and a drive train for a vehicle having such a transmission assembly. Background Art

[0002] A lubricant supply system for a drive device of an electrically operated vehicle is known from DE 10 2021 112 967 B3. The drive device has at least one electric motor, and the electric motor drives at least one vehicle wheel via a transmission assembly. An electric motor hydraulic circuit is provided, in which a lubricant tank is connected to a pressure pump via a suction line, and the pressure pump can transport the lubricant into the electric motor via an electric motor supply line. The pressure pump, as a common pressure pump, belongs not only to the electric motor hydraulic circuit but also to a transmission hydraulic circuit, so that in the pumping operation, the lubricant can circulate not only in the electric motor hydraulic circuit but also in the transmission hydraulic circuit. The electric motor hydraulic circuit and the transmission hydraulic circuit also have a lubricant sump and a return pump as additional common components. The transmission assembly has an axle differential, which is drivingly connected to the vehicle wheels on both sides via flange shafts on the output side. In addition, one of the flange shafts is divided into a wheel-side shaft section and an axle-side shaft section, which can be coupled to each other via a disconnect clutch. The lubricant supply system also has a disconnect clutch hydraulic circuit, via which lubricant can be supplied to the disconnect clutch. The lubricant can be guided to the disconnect clutch in at least one disconnect clutch supply line. The lubricant flowing out of the disconnect clutch collects in a common lubricant sump. Summary of the Invention

[0003] The object of the present invention is to provide a transmission assembly with an improved coolant or lubricant supply, which supplies the components to be cooled or lubricated of the transmission components, in particular with fewer oil pressure holes in the internal central shaft. This object is solved by a transmission assembly having the features of independent claim 1 and a drive train having the features of claim 10. Advantageous embodiments of the present invention are the subject matter of the dependent claims, the following description, and the drawings.

[0004] The transmission assembly for a drive train of a vehicle according to the invention comprises a planetary gear set having a planet carrier on which at least one bolt is arranged, on which a first bearing element for rotatably supporting the planet gears is arranged, wherein the transmission assembly further has a differential drive-connected to the planet carrier, which transfers the drive power acting on the planet carrier to a first central shaft and a second central shaft coaxially arranged with the first central shaft, wherein at least the first central shaft has a central first passage for supplying coolant and / or lubricant to the interior space of the differential, and wherein at least one at least sectionally radially extending first hole is constructed in the planet carrier in order to guide the coolant and / or lubricant from the interior space of the differential into a second passage of the bolt.

[0005] Due to the diameter limitations of the drive unit of the drive train, especially when configured as an electric motor, or other restrictive structures of the drive train, it is not possible to arbitrarily increase the diameter of the central shaft to compensate for the increased stress concentration at the transverse holes of the central shaft. However, with the transmission assembly proposed here, the pressure oil applied to the transverse holes of the first central shaft can be reduced, because the coolant or lubricant can be supplied via the differential, and the interior space of the differential is supplied with oil via the first passage of the first central shaft. Therefore, a certain amount of coolant or lubricant accumulates in the differential and is distributed from there, or in particular diverted to the bearings and teeth of the planetary gear set.

[0006] In addition to the planet carrier and at least one planet gear, the planetary gear set further comprises a sun gear and a ring gear, wherein the planet gears are in tooth engagement with both the sun gear and the ring gear. The "planetary gear set" should in particular be understood as a unit having a sun gear, a ring gear and a plurality of planet gears guided by the planet carrier along an annular track around the sun gear. Advantageously, the respective planetary gear set has exactly one fixed-axis transmission ratio. During the formation of the planet carrier as the driven member of the planetary gear set, the drive of the planetary gear set can be carried out via the sun gear or the ring gear, while the other member is preferably fixed relative to the housing and thus arranged against relative rotation. In one embodiment, the sun gear is operatively connected to a drive unit (such as an electric motor or an internal combustion engine), while the ring gear is stationary. The planetary gear set converts the input drive power and drives the differential housing of the differential. The planetary gear set is part of a planetary transmission, wherein the planetary transmission can further comprise additional planetary gear sets.

[0007] In addition to the differential housing, the differential further includes axle shafts in the form of bolts or shafts having a circular cross-section. The axle shafts are firmly arranged within the differential housing, wherein at least one, preferably two, cylindrical gears are rotatably arranged on the axle shafts. The two cylindrical gears respectively mesh with a first axle shaft gear and a second axle shaft gear, the first axle shaft gear being non-rotatably connected to a first central shaft, and the second axle shaft gear being non-rotatably connected to a second central shaft. The non-rotatable connection is preferably achieved via splines. The central shafts are understood to be driven shafts of the drive train, via which the wheels of the vehicle axle can be driven. Thus, the central shafts are configured to be at least indirectly drivingly connected to the associated wheels of the vehicle.

[0008] The planetary gear set and the differential form a geometric unit. This is understood to mean that a part of the planet carrier can assume the function of the differential, in particular the function of the differential housing, and / or a part of the differential housing can assume the function of the planet carrier. Thus, the differential housing rotates together with the planet carrier.

[0009] When the planet carrier and the differential housing rotate about their axis of rotation, the cylindrical gears also move about the axis of rotation of the planet carrier. The cylindrical gears can also rotate about their own axes, i.e., about the longitudinal axes of the small axle shafts. The cylindrical gears ensure that the wheel axle shafts can rotate at different speeds, while the torque and rotational movement continue to be transmitted to the components connected to the wheel axle shafts or the central shafts, in particular the wheels of the vehicle.

[0010] When the vehicle is traveling in a straight line, forces act on the two wheels of the vehicle axle to the same extent, so that the cylindrical gears do not rotate about their own axes because they rotate together with the differential housing. They transmit the torque to the axle shaft gears, causing these axle shaft gears to rotate and thus indirectly driving the wheels. When the vehicle is turning, due to the different rotational speeds of the wheel axle shafts or the central shafts, the cylindrical gears all rotate forward, but at different speeds. The speed difference between the axle shaft gears is inversely proportional. In an improved embodiment, the differential can be configured as a limited-slip differential, wherein the differential can include corresponding coupling elements for coupling the central shafts to each other.

[0011] A first channel, preferably located on the axis of rotation of the first central axis, is provided for fluid connection to a coolant and / or lubricant supply. Thus, the coolant or lubricant is conveyed at least indirectly into the first channel by means of a pump and introduced into the transmission assembly via the first channel, more precisely into the interior space of the differential, where the coolant or lubricant is distributed from the interior space of the differential to the components of the planetary gear set to be cooled or lubricated. The interior space is understood to be the space of the differential bounded spatially by the cylindrical gears, the axle shaft gears and the end sides of the central shaft. The axle shaft of the differential passes through the interior space of the differential. All of the coolant or lubricant is collected in the interior space and distributed outward, with the support of the acting centrifugal force, to the tooth parts and bearing elements of the transmission assembly, in particular of the planetary gear set.

[0012] The first hole is arranged on the planet carrier in such a way that coolant or lubricant from the interior space of the differential can be intercepted and guided to a second channel of the bolt, where the second channel conveys the coolant or lubricant to the first bearing element supported in a rotatable manner. Depending on where the first hole opens into the second channel, the second channel can have an axial section and a radial section. The first hole has at least one radial component, so that the first hole is understood as a transverse hole. This can be understood as the expression "at least sectionally radially extending". The first hole can additionally also have an axial component, so that the first hole can also be formed at least sectionally in the form of an inclined hole. The first hole can also have an axially extending section, however, where the coolant or lubricant is in principle guided radially outward. Thus, an optional section is provided for receiving coolant or lubricant from the radial section of the first hole and / or for conveying coolant or lubricant to the radial section of the first hole.

[0013] In this embodiment, the differential and the planet carrier act as a geometric unit, and all the oil accumulated in the differential can overflow at least through the first hole in the planet carrier and thus reach the bearing elements and tooth parts to be cooled or lubricated.

[0014] The first central shaft is arranged radially inside the planetary gear set. The first central shaft is arranged coaxially with the longitudinal axis of the planetary gear set. The first central shaft is arranged radially inside the sun gear and the input shaft of the transmission assembly. The input shaft is provided for guiding the drive power of the drive unit into the transmission assembly. The first central shaft is arranged radially inside the planet carrier.

[0015] The planet carrier preferably has an axial section on which the sun gear of the planetary gear set is rotatably supported via at least one second bearing element. The axial section of the planet carrier can be sectionally radially arranged between the first central shaft and the first sun gear.

[0016] Preferably, at least one second hole extending at least sectionally radially is configured on the axial section of the planet carrier for supplying coolant and / or lubricant to the second support element. The second support element may be a radial bearing, in particular a needle bearing or a sliding bearing. The radial force is transmitted between two components by means of the radial bearing. The needle bearing or the sliding bearing saves radial structural space. The second support element is preferably arranged radially between the axial section of the planet carrier and the sun gear. The second support element and the second hole may be located in a common radially extending plane. In other words, the second support element and the second hole are arranged at the same axial position.

[0017] Furthermore preferably, at least one third hole extending at least sectionally radially is also configured on the axial section of the planet carrier for supplying coolant and / or lubricant to the third support element for supporting the sun gear on the planet carrier. The third support element is preferably a thrust bearing, in particular a cylindrical roller bearing. The axial force can be transmitted between two components by means of the thrust bearing.

[0018] The third hole is preferably configured to also supply coolant and / or lubricant to the first tooth section between the sun gear and the planet gear of the planetary gear set. Therefore, the third support element and the first tooth section between the sun gear and the planet gear of the planetary gear set are lubricated or cooled via the third hole.

[0019] In one embodiment, the second hole and / or the third hole are fluidly connected to the interior space of the differential via a spline between the first central shaft and the first bridge shaft gear meshing therewith. In other words, a part of the coolant or lubricant from the interior space of the differential is guided to the axial section of the planet carrier via the spline that non-rotationally connects the first central shaft and the first bridge shaft gear, where the coolant or lubricant can be further distributed via the second hole or the third hole. During the operation of the drive train, gaps are configured on the tooth surfaces of the spline according to the torque direction, and the coolant or lubricant can reach from one end of the spline to the other end through the gaps. Optionally, individual teeth of the internal tooth section of the first bridge shaft gear and / or individual teeth of the external tooth section of the first central shaft may be missing on the spline so that the desired volume of coolant or lubricant can be guided to the required position.

[0020] The first hole of the planet carrier is preferably fluidly connected to the interior space of the differential via a second tooth section between the first cylindrical gear of the differential and the first bridge shaft gear meshing therewith. In other words, a part of the coolant or lubricant from the interior space of the differential is guided to the first hole via the second tooth section and reaches the second channel of the bolt via the first hole.

[0021] In an improved embodiment of the present invention, a perforated end partition is arranged in the first channel of the first central shaft. The end partition defines the amount of coolant or lubricant entering the internal space. In other words, the amount of coolant or lubricant entering the internal space of the differential is the same as the amount required for lubricating or cooling the components or tooth parts. Therefore, losses, especially splash losses or similar losses, can be avoided or at least reduced. The end partition may have holes or perforations, which help to regulate the pressure in the first channel.

[0022] Preferably, the first central shaft has at least one transverse hole. The coolant or lubricant can be radially diverted outward via the transverse hole before entering the internal space, so as to cool or lubricate the components of the planetary gear set. The transverse hole of the first central shaft can in particular be provided for supplying coolant or lubricant to the second hole and / or the third hole of the axial section of the planet carrier. In this case, the coolant or lubricant is not guided through the internal space, but can be directly guided to the desired position, provided that the respective transverse hole does not have a negative impact on the load-bearing capacity of the relatively thin first central shaft. Therefore, it is also conceivable to provide more than one transverse hole on the first central shaft.

[0023] The drive train for a vehicle according to the present invention includes a transmission assembly and a drive unit according to the above-described embodiments. The drive train can be used in a vehicle. The vehicle is preferably a motor vehicle, especially an automobile (for example, a passenger vehicle with a weight of less than 3.5 tons), a bus or a heavy vehicle (for example, a bus and a heavy vehicle with a weight of more than 3.5 tons). In particular, the vehicle is an electric vehicle or a hybrid vehicle. The vehicle includes at least two axles, wherein one of the axles forms an axle that can be driven by the drive train. The drive train according to the present invention is effectively arranged on the drivable axle, wherein the drive train transmits the drive power of the drive unit to the wheels of the axle at least indirectly via the transmission assembly. It is also conceivable to provide such a drive train for each axle. The drive train is preferably constructed in a front-transverse configuration, such that the drive shaft of the drive unit and the input shaft of the transmission assembly are substantially oriented transversely to the longitudinal direction of the vehicle. Alternatively, the drive train can be arranged obliquely with respect to the longitudinal axis and the transverse axis of the vehicle, wherein the output shaft is connected to the wheels of the respective axle arranged transversely to the longitudinal axis of the vehicle via corresponding joints.

[0024] In this regard, the term "at least indirectly" is understood to mean that two components are connected to each other (act) via at least one additional component arranged between the two components, or directly and thus directly connected to each other. Therefore, additional components acting on the shaft or gear can also be arranged between the shaft or gear.

[0025] The "driving connection" of the components is understood to mean that these components can either be directly connected to each other, for example, connected to each other against relative rotation, or can be indirectly connected to each other via at least one additional component, for example, via at least one additional shaft and / or at least one additional gear.

[0026] The above definitions and explanations of the technical effects, advantages and advantageous embodiments of the transmission assembly according to the invention also apply mutatis mutandis to the drive train according to the invention, and vice versa. Brief Description of the Drawings

[0027] Embodiments of the present invention will be explained in detail below with reference to schematic diagrams, in which identical or similar components are provided with the same reference numerals. Among them:

[0028] Figure 1 A highly schematic top view of a vehicle having a drive train according to the invention and a transmission assembly according to the invention in accordance with a preferred embodiment is shown; and

[0029] Figure 2 Only a part of the highly simplified longitudinal sectional view of the transmission assembly according to Figure 1 of the present invention is shown. Detailed Description of the Invention

[0030] According to Figure 1 , the vehicle F has two vehicle axles 29a, 29b, wherein a drive train 2 according to the invention is arranged on the first vehicle axle 29a in a driving manner (that is to say, is used to drive the wheels 30 of the vehicle F). The vehicle F is an electric vehicle here, and the drive of the vehicle F is carried out purely electrically. The first axle 29a can be either the front axle or the rear axle of the vehicle F and forms the drive vehicle axle of the vehicle F. Currently, the first vehicle axle 29a is the non-steerable rear axle of the vehicle F.

[0031] According to Figure 1 Combined with Figure 2 , the drive train 2 includes a transmission assembly 1, wherein the drive power of the drive unit 3 configured as an electric motor is transmitted to the differential 9 via the transmission assembly 1, and the differential distributes the drive power to the first central shaft 10 and the second central shaft 11. The central shafts 10, 11 are used as the output shafts or driven shafts of the drive train 2 and are respectively connected to the wheels 30 of the mentioned first axle 29a.

[0032] The transmission assembly 1 includes a planetary gear set 4, which has a sun gear 17 that can be rotationally driven via an input shaft 31 (this sun gear functions as the driving part of the planetary gear set 4), a planet carrier 5 that functions as the driven part of the planetary gear set 4, and a ring gear (not shown here) that is fixedly arranged, that is, arranged against relative rotation. According toFigure 1 The input shaft 31 is drivingly connected to the drive unit 3. A bolt 6 is fastened to the planet carrier 5, and first support elements 7 are respectively arranged on the bolt for rotatably supporting the associated planet gears 8.

[0033] The differential 9 drivingly connected to the planet carrier 5 has a differential housing 33 firmly connected to the planet carrier 5 via a screw 32. A bridge shaft 36 is fastened to the differential housing. Cylindrical gears 26, 34 are rotatably and spaced apart from each other on the bridge shaft. The cylindrical gears 26, 34 mesh with two bridge shaft gears 25, 35, and the bridge shaft gears are respectively connected to the coaxially arranged central shafts 10, 11 in a rotationally resistant manner via splines 24. The driving power converted by the planetary gear set 4 is distributed to the two central shafts 10, 11 via the mentioned components of the planet carrier 5 and the differential 9.

[0034] The first central shaft 10 has a central first passage 12. Coolant and / or lubricant is transported through this first passage by a coolant and / or lubricant supply (not shown here, for example, configured as a pump) into the interior space 13 of the differential 9. A perforated end partition 27 is arranged in the first passage 12, and a defined amount of coolant or lubricant is allowed to enter the interior space 13 of the differential 9 per unit time by means of this perforated end partition.

[0035] The planet carrier 5 has an axial section 16. The sun gear 17 of the planetary gear set 4 is rotatably supported and radially supported on this axial section via a second support element 18 configured as a needle bearing. The sun gear 17 is also supported on the planet carrier 5 via a third support element 21 configured as a cylindrical roller bearing as a thrust bearing and is supported in a manner that can rotate relative to the planet carrier.

[0036] The coolant or lubricant is transported outwards from the interior space 13 in order to cool or lubricate the support elements and tooth parts of the transmission assembly 1, in particular the planetary gear set 4. The flow direction of the coolant or lubricant is indicated by a dashed arrow P. A plurality of holes 14, 19, 20 that at least partially extend radially are provided on the planet carrier 5. In this example, the first hole 14 is implemented obliquely relative to the longitudinal axis L of the planetary gear set 4 or relative to the rotational axis of the central shafts 10, 11 in order to guide a part of the coolant or lubricant emerging from the interior space 13 of the differential 9 into the second passage 15 of the bolt 6. Currently, the first hole 14 directly leads into the second passage 15 in order to supply coolant or lubricant to the first support element 7.

[0037] On the axial section 16 of the planet carrier 5, a second hole and a third hole 19, 20 are also formed, which extend substantially radially. Coolant or lubricant is supplied to the second support element 18 via the second hole 19. Coolant or lubricant is supplied to the third support element 21 and the first tooth part 22 between the sun gear 17 and the planet gear 8 via the third hole 20. In addition, the first central shaft 10 also has at least one transverse hole 28 for supplying coolant or lubricant to the second support element 18. The first central shaft 10 may have additional transverse holes for supplying coolant or lubricant to the components of the transmission assembly 1, which will not be discussed in detail at present.

[0038] A part of the coolant or lubricant reaches the first hole 14 from the internal space 13 of the differential 9 via the second tooth part 23 between the first cylindrical gear 26 of the differential 9 and the first bridge shaft gear 25 meshing therewith. Another part of the coolant or lubricant reaches the second and third holes 19, 20 from the internal space 13 of the differential 9 via the spline 24 between the first central shaft 10 and the first bridge shaft gear 25 meshing therewith.

[0039] List of reference numerals

[0040] 1 Transmission assembly

[0041] 2 Drivetrain

[0042] 3 Drive unit

[0043] 4 Planet gear set

[0044] 5 Planet carrier of the planet gear set

[0045] 6 Bolt

[0046] 7 First support element

[0047] 8 Planet gear

[0048] 9 Differential

[0049] 10 First central shaft

[0050] 11 Second central shaft

[0051] 12 First channel

[0052] 13 Internal space of the differential

[0053] 14 First hole

[0054] 15 Second channel

[0055] 16 Axial section of the planet carrier

[0056] 17 Sun gear of the planet gear set

[0057] 18 Second support element

[0058] 19 The second hole

[0059] 20 The third hole

[0060] 21 The third support element

[0061] 22 The first tooth part

[0062] 23 The second tooth part

[0063] 24 Spline

[0064] 25 The first axle gear of the differential

[0065] 26 The first cylindrical gear of the differential

[0066] 27 End partition

[0067] 28 Transverse hole

[0068] 29a The first vehicle axle

[0069] 29b The second vehicle axle

[0070] 30 Wheel

[0071] 31 Input shaft

[0072] 32 Screw

[0073] 33 Differential housing

[0074] 34 The second cylindrical gear of the differential

[0075] 35 The second axle gear of the differential

[0076] 36 Axle

[0077] F Vehicle

[0078] L Longitudinal axis

[0079] P Arrow

Claims

1. A transmission assembly (1) for a drive train (2) of a vehicle, the transmission assembly including a planetary gear set (4) having a carrier (5), on which at least one bolt (6) is arranged, wherein, Arranged on the bolt (6) is a first support element (7) for rotatably supporting the planet gear (8), wherein the transmission assembly (1) further has a differential (9) drivingly connected to the planet carrier (5), and the differential transmits the driving power acting on the planet carrier (5) to a first central shaft (10) and a second central shaft (11) coaxially arranged with the first central shaft. At least the first central shaft (10) has a central first channel (12) for supplying coolant and / or lubricant to the internal space (13) of the differential (9). At least one first hole (14) extending at least sectionally radially is formed in the planet carrier (5) to guide the coolant and / or lubricant from the internal space (13) of the differential (9) into a second channel (15) of the bolt (6).

2. The drive assembly (1) according to claim 1, wherein, The planet carrier (5) has an axial section (16), and the sun gear (17) of the planet gear set (4) is rotatably supported on the axial section via at least one second support element (18).

3. The drive unit assembly (1) according to claim 2, wherein, At least one second hole (19) extending at least sectionally radially is formed in the axial section (16) of the planet carrier (5) to supply coolant and / or lubricant to the second support element (18).

4. The transmission device assembly (1) according to any one of the preceding claims, wherein, At least one third hole (20) extending at least sectionally radially is formed in the axial section (16) of the planet carrier (5) to supply coolant and / or lubricant to a third support element (21) for supporting the sun gear (17) on the planet carrier (5).

5. The drive assembly (1) according to claim 4, wherein, The third hole (20) is also configured to supply coolant and / or lubricant to a first tooth portion (22) between the sun gear (17) and the planet gear (8) of the planet gear set (4).

6. The drive assembly (1) according to any one of claims 3 to 5, wherein, The second hole (19) and / or the third hole (20) are fluidly connected to the internal space (13) of the differential (9) via a spline (24) between the first central shaft (10) and a first bridge shaft gear (25) of the differential (9) meshing with the first central shaft.

7. The drive assembly (1) according to any one of the preceding claims, wherein, The first hole (14) of the planet carrier (5) is fluidly connected to the internal space (13) of the differential (9) via a second tooth portion (23) between a first cylindrical gear (26) of the differential (9) and a first bridge shaft gear (25) of the differential (9) meshing with the first cylindrical gear.

8. The drive assembly (1) according to any one of the preceding claims, wherein, A perforated end partition (27) is arranged in the first channel (12) of the first central shaft (10).

9. The drive assembly (1) according to any one of the preceding claims, wherein, The first central shaft (10) has at least one transverse hole (28).

10. A drive train (2) for a vehicle, the drive train including a drive unit (3) and a transmission assembly (1) according to any one of the preceding claims.

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