Drive unit and motor vehicle
Patent Information
- Application Number
- PCT/DE2026/100046
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2025-02-21
- Filing Date
- 2026-01-20
- Publication Date
- 2026-08-27
Smart Images
Figure DE2026100046_27082026_PF_FP_ABST
Abstract
Description
[0001] 24-2782
[0002] 1
[0003] drive unit and motor vehicle
[0004] The present invention relates to a drive unit for a purely electric or hybrid-electric motor vehicle and to a motor vehicle comprising such a drive unit.
[0005] In vehicle manufacturing, there is a need to minimize friction losses in the powertrain to enable particularly energy-efficient and low-emission operation of the vehicle. This requires implementing rolling bearings for shafts used in the powertrain with the lowest possible friction. Prior art approaches in which rolling bearings are lubricated by a pasty lubricant (usually grease) that does not need to be replaced or refilled over the bearing's lifetime—so-called lifetime grease-lubricated rolling bearings—inadequately meet current requirements for friction efficiency. Conventional bearing arrangements in electric drive units for motor vehicles are known, for example, from DE 102022 120760 A1 or DE 102021 125658 A1.
[0006] The object of the present invention is to minimize friction losses occurring in the drive train of a motor vehicle during ferry operation.
[0007] This problem is solved by the subject matter of the independent claims. Further possible embodiments of the invention are disclosed in the dependent claims, the description, and the figures. Features, advantages, and possible embodiments discussed in 24-2782
[0008] 2
[0009] The features set out in the description for one of the subject matter of the independent claims are to be regarded, at least analogously across categories and embodiments, as features, advantages and possible embodiments of the respective subject matter of the other independent claims as well as of any possible combination of the subject matter of the independent claims, possibly in conjunction with one or more of the dependent claims.
[0010] According to the invention, a drive unit for a motor vehicle and a motor vehicle comprising the drive unit are proposed. In its intended installation position, the drive unit forms a component of the motor vehicle that can be driven purely electrically or hybrid-electrically and consequently has an electric machine or an electromechanical converter on board as a traction machine.
[0011] The drive unit comprises a housing and a differential gear arranged within the housing, which is designed, for example, as a bevel gear differential or a spur gear differential. A differential cage of the differential gear is mounted in the housing, in particular by means of cage bearings of the drive unit. The cage bearings are arranged within the housing, that is, within a housing chamber bounded by an outer housing wall. Specifically, exactly two cage bearings are provided, but three or more cage bearings are also possible. A differential gear set is arranged in a differential gear chamber of the differential gear, comprising a first and a second differential output gear and a differential gear set.The differential output gears are both rotatably mounted along a differential main axis of the differential in the differential gear chamber on the differential cage, whereas the differential gears of the differential gear set are rotatably mounted perpendicular to the differential main axis in the differential gear chamber on the differential cage and each mesh with both differential output gears.
[0012] Furthermore, the drive unit has a connecting shaft, the first end of which is non-rotatably connected to a first differential output gear of the differential. Therefore, the differential main axis and a connecting shaft main axis coincide. A second end of the connecting shaft is supported in the housing by means of a connecting shaft roller bearing of the drive unit. In particular, exactly one connecting shaft roller bearing is provided. It should be understood that the connecting shaft roller bearing is present in addition to the cage bearings. The connecting shaft roller bearing is arranged in the housing, that is, within the housing chamber bounded by the outer housing wall. 24-2782
[0013] 3
[0014] Furthermore, the drive unit features a lubrication circuit in which the differential gear and the connecting shaft roller bearing are integrated. In particular, the cage roller bearings are also integrated into the lubrication circuit. A lubricant – specifically a lubricating and cooling agent, such as oil – is supplied to the differential gear and the roller bearings via this lubrication circuit. For this purpose, the lubrication circuit includes, for example, a flow control and / or steering unit designed to selectively supply lubricant to the differential gear, especially its differential gear set, and to the roller bearing(s).The flow control and / or steering unit has, for example, at least one spray nozzle for spraying lubricant onto the component to be lubricated / cooled and / or at least one lubricant sump in which the component to be lubricated / cooled is immersed. Unlike in the prior art, the connecting shaft roller bearing is not designed as a lifetime grease-lubricated roller bearing and is, in particular, integrated into the lubricant circuit. During operation of the drive unit, lubricant, especially from the differential gear chamber, is supplied to the connecting shaft roller bearing by means of the fluid delivery unit.
[0015] To ensure that the connecting shaft bearing receives a sufficient supply of lubricant or lubricant / coolant during operation of the drive unit, the connecting shaft incorporates a fluid delivery unit. This unit is designed to transport lubricant from the differential gear chamber along the differential main axis to the connecting shaft bearing during operation of the drive unit. Specifically, the fluid delivery unit is purely passive, meaning it operates without a separate moving part for fluid transport, i.e., without a motor-driven pump, etc. Therefore, the connecting shaft can form part of the lubrication circuit, particularly for the flow control and / or steering unit.
[0016] This design of the drive unit makes it easy and cost-effective to efficiently and reliably supply the connecting shaft bearing with a liquid lubricant. This results in lower-friction rolling operation of the connecting shaft bearing and, consequently, an overall higher efficiency of the drive unit. A conventional, lifetime grease-lubricated rolling bearing is therefore unnecessary. Moreover, the connecting shaft rolling bearing described herein is more durable than a lifetime grease-lubricated rolling bearing. The term "rolling bearing" here refers to all bearing types in which rolling elements are arranged between an inner and an outer bearing ring.24-2782
[0017] 4
[0018] These are bearings suitable for radially and / or axially supporting a rotating component during operation. The rolling bearings described herein may, for example (but are not limited to), be ball bearings, cylindrical roller bearings, needle roller bearings, tapered roller bearings, spherical roller bearings, or toroidal roller bearings. A double-row bearing and two directly adjacent single bearings are considered a single bearing within this context.
[0019] According to another possible embodiment, the fluid conveying unit has a hollow connecting shaft body. This means that the connecting shaft is designed as a hollow shaft along its entire longitudinal extent, so that the connecting shaft has two end-face hollow shaft openings which communicate fluidically with each other. The hollow shaft body, i.e., one of the hollow shaft openings, opens into the differential gear chamber in which the differential gear set is arranged. Furthermore, a fluid conveying structure is formed along an inner surface of the hollow shaft body, which is designed to transport a fluid, in particular the lubricant, along the main axis of the connecting shaft through the hollow shaft body and thus to the connecting shaft roller bearing. The fluid conveying structure is, in particular, designed as a helical structure or has one.The helical structure either dips concavely into the inner surface or protrudes convexly from it. In particular, when designing the fluid conveying unit or the helical structure, the helix direction (i.e., whether the helical structure is right-handed or left-handed) is selected such that, when the connecting shaft is rotated in its preferred direction, the lubricant is driven by the helical structure towards the connecting shaft's roller bearing. Furthermore, the hollow connecting shaft has a through-hole for fluid flow, which opens on one side onto the inner surface of the hollow shaft body and on the other side, on the outer circumference, into a bearing seat of the connecting shaft in which the connecting shaft's roller bearing is located. The through-hole can be arranged obliquely or perpendicularly to the main axis of the connecting shaft. Two or more such through-holes can also be provided.The preferred direction of rotation is particularly associated with the forward direction of travel of the vehicle. Thanks to the fluid conveying structure integrated into the connecting shaft, a simple and particularly space-efficient method is created to convey lubricant towards the connecting shaft's roller bearings. The connecting shaft, or rather its hollow shaft body, functions as part of the lubrication circuit. 24-2782.
[0020] 5
[0021] According to another possible embodiment, the drive unit comprises an electric machine or an electromechanical converter, thereby forming a traction machine of the drive unit. When the drive unit is installed in its intended position in the vehicle, the traction machine of the drive unit can constitute the electric traction machine or one of two or more traction machines of the vehicle. The traction machine, which can be designed as an axial flux machine or a radial flux machine, comprises a rotor-stator unit whose rotor and stator are arranged along a longitudinal center axis of the stator, with the rotor being rotatably mounted along this axis. A rotor shaft is non-rotatably connected to the rotor and is directly or indirectly coupled to a cage gear of the differential for torque transmission.The cage gear ring is connected to the differential cage by force-fit, form-fit, and / or material-fit connections to prevent rotation. The rotor shaft is supported in the housing by means of rotor shaft bearings of the drive unit located within the housing. The rotor shaft bearings are therefore arranged within the housing chamber. For example, exactly two rotor shaft bearings are provided. Two or more rotor shaft bearings can just as easily be used. The rotor-stator unit can be arranged between two of the rotor shaft bearings, so that the rotor shaft, which then protrudes from the stator on both sides, is supported on both sides of the stator.
[0022] Furthermore, both the rotor-stator unit of the traction machine and the rotor shaft bearings are integrated into the lubrication circuit. In particular, the traction machine can be designed as a so-called wet-rotor machine, which means that during operation requiring temperature control, especially cooling, the rotor-stator unit is in direct contact with the lubricant / coolant, and is specifically surrounded by it. It should be understood that, at least in this case, the lubricant is not electrically conductive or dielectric. Thus, the lubricant / coolant lubricates both the rotor shaft bearings and cools the rotor-stator unit. Peripheral components of the traction machine requiring temperature control or cooling, such as an inverter and / or control unit, can also be integrated into the lubrication circuit.The aforementioned peripheral components can be integrated into the lubrication circuit in such a way that electrical / electronic components of the periphery are directly immersed in the lubricant / coolant (immersion cooling). The lubrication circuit is used particularly efficiently because it is employed not only to supply lubricant to the cage bearings and the connecting shaft bearing, but also to supply lubricant to the rotor shaft bearings and for cooling.24-2782
[0023] 6
[0024] the rotor-stator unit. A separate cooling system for the rotor-stator unit is not required in the drive unit and consequently in the vehicle, which, among other things, results in a weight advantage.
[0025] The cage gear ring and the differential cage can be formed in one piece. Between the rotor shaft and the cage gear ring—as provided for in a possible further development of the drive unit—exactly one spur gear stage is formed, which is arranged in the housing or housing chamber and integrated into the lubrication circuit. In this case, the rotor shaft and a rotor shaft pinion are coaxially and rotationally fixed to one another, with the rotor shaft pinion and the cage gear ring meshing directly with each other, thus forming the single spur gear stage. Furthermore, according to this further development, the lubrication circuit has a flow guide and / or steering unit, which is designed to selectively supply lubricant to a tooth engagement zone of the first spur gear stage during operation of the drive unit, while the rotor shaft pinion and the cage gear ring are rolling against each other.The flow guidance and / or steering unit can, for example, include a spray nozzle for applying lubricant to the gear meshing zone and / or a lubricant sump in which the rotor shaft pinion and / or the cage gear ring splash. This further expands the operating range of the lubricant circuit, and a separate lubrication system for the spur gear stage can be omitted in the drive unit.
[0026] In an alternative embodiment, the drive unit has one or more intermediate shafts, each intermediate shaft being supported in the housing by means of intermediate shaft bearings. The intermediate shaft bearings are located within the housing, i.e., inside the housing chamber. An intermediate shaft pinion and an intermediate shaft gear are coaxially and rotationally fixed to each intermediate shaft. Specifically, exactly two intermediate shaft bearings are provided per intermediate shaft; however, three or more intermediate shaft bearings per intermediate shaft are also conceivable. It is also possible that one or more intermediate shaft bearings are arranged axially between the intermediate shaft pinion and the intermediate shaft gear on each intermediate shaft.This results in the drive unit having a spur gear stage involving the intermediate shaft pinion and a spur gear stage involving the intermediate shaft gear, with, for example, the intermediate shaft pinion and the rotor shaft pinion meshing with each other, while the intermediate shaft gear and the cage ring gear meshing with each other. For example, the drive unit has only this one (first) intermediate shaft and consequently exactly 24-2782.
[0027] 7
[0028] the two spur gear stages. In this process, one or both of the spur gear stages, as well as the intermediate shaft bearings, are integrated into the lubrication circuit.
[0029] Embodiments in which the drive unit has two or more intermediate shafts and a corresponding number of spur gear stages are equally conceivable; for each additional intermediate shaft, the number of spur gear stages increases by 1. The intermediate shaft pinion of a further (for example, second) intermediate shaft then meshes with the intermediate shaft gear of the first intermediate shaft, with the intermediate shaft gear of the second intermediate shaft meshing with the cage ring gear or – if present – with an intermediate shaft pinion of yet another (for example, third) intermediate shaft. In any case, the cage ring gear meshes with the intermediate shaft gear of the last of the intermediate shafts. One, some, or all of the spur gear stages – as well as one, some, or all of the intermediate shaft roller bearings – are integrated into the lubrication circuit. In any case, the lubrication circuit is used even more efficiently, and a separate lubrication system for the intermediate shaft roller bearings is no longer necessary.The spur gear stages present due to the intermediate shaft(s) can be omitted. Therefore, the drive unit can be designed to be particularly lightweight and mass-efficient.
[0030] According to another possible embodiment, the drive unit has a first and a second main output shaft, which have a common, identical geometry and size, meaning they are designed as identical parts and are therefore readily interchangeable. The first main output shaft—in particular its first end—is rotationally fixed to a second differential output gear of the differential (the main output shaft and the rest of the drive unit are not assembled or are separate) or connected (the main output shaft and the rest of the drive unit are assembled as intended), whereas the second main output shaft—in particular its first end—is rotationally fixed to or connectable to the connecting shaft. For this purpose, it is specifically provided that the first main output shaft (or its first end) and the second differential output gear are connected to the connecting shaft.the second main output shaft (or its first main output shaft end) and the connecting shaft are connected / connectable to each other in a rotationally fixed manner by means of a respective splined shaft-splined hub connection.
[0031] The respective main output shaft has in particular a constant velocity joint, in particular two constant velocity joints, to prevent movement of the respective main output shaft in relation to the differential main axis or to a longitudinal center axis of a respective second main-24-2782
[0032] 8
[0033] to enable the driven component of the drive unit or vehicle to be attached to the output shaft end. The respective driven component can be, for example, a vehicle wheel (i.e., a tire-rim combination) if the drive unit is installed transversely in the vehicle as an axle drive unit, or a transverse transfer case if the drive unit is installed longitudinally in the vehicle as a central drive unit between two drive axles.
[0034] Once the second main output shaft is properly connected to the connecting shaft, the second main output shaft and the connecting shaft can form a combined shaft of the drive unit or the vehicle, with the combined shaft comprising the second main output shaft and the connecting shaft as sub-shafts. If the main output shafts are provided or used as identical components, the drive unit is positioned centrally between the driven assemblies, with the connecting shaft bridging a gap between the first differential output gear and a connection point where the connecting shaft is / can be connected to the second main output shaft. By designing the first and second main output shafts as identical components, the drive unit, and consequently the vehicle, can be manufactured particularly easily and with minimal effort. Furthermore, the drive unit can be designed with particular flexibility.variable, especially across different models or series.
[0035] A possible further development of the vehicle containing the drive unit provides that the drive unit is installed as an axle drive unit transversely to a longitudinal axis of the vehicle, with the differential main axis and a transverse axis of the vehicle being arranged parallel to each other. In this case, the two uniform main output shafts are designed as uniform wheel drive shafts, the second main output shaft ends of which are rotationally fixed to a wheel hub of the vehicle. A wheel of the vehicle can be rotationally fixed to each wheel hub.It is conceivable that the motor vehicle has two or more drive units, for example (but not limited to) a first drive unit designed as an axle drive unit for driving a first axle of the motor vehicle and / or a second drive unit designed as an axle drive unit for driving a second axle of the motor vehicle. Alternatively or additionally, the motor vehicle may have a drive unit designed as a central drive unit. By using the drive unit as an axle drive unit, a drive axle of the motor vehicle, and consequently the motor vehicle itself, can be manufactured particularly simply, especially with the aid of a24-2782.
[0036] 9
[0037] Modular construction, where the drive axle is an element of the modular system.
[0038] Further features of the invention may become apparent from the claims, the figures, and the description of the figures. The features and combinations of features mentioned above in the description, as well as the features and combinations of features shown below in the description of the figures and / or in the figures themselves, can be used not only in the combinations specified, but also in other combinations or individually, without departing from the scope of the invention.
[0039] The drawing shows in
[0040] Fig. 1 shows a schematic view of a motor vehicle having a drive unit, which is highly schematically represented in a transmission topology view, and in
[0041] Fig. 2 shows a schematic and cutaway view of a differential gear and a connecting shaft of the drive unit.
[0042] In the following, a drive unit 1 and a motor vehicle 2 are described together. In the figures, identical and functionally equivalent elements are designated with the same reference numeral.
[0043] Fig. 1 shows the motor vehicle 2, which is designed to be driven / propelled purely electrically or hybrid-electrically and includes the drive unit 1 as a component. In this case, the drive unit 1 is part of a drive axle 3 of the motor vehicle 2. The drive axle 3 can be a first axle, in particular a front axle, of the motor vehicle 2, or a second axle, in particular a rear axle, of the motor vehicle 2. Here, the drive unit 1 is installed as an axle drive unit transversely to a longitudinal axis x of the motor vehicle, and consequently parallel to a transverse axis y of the motor vehicle. It is conceivable that the motor vehicle is equipped with a multi-axle drive, which can be implemented, for example, by the motor vehicle 2 having two or more drive axles 3, or by the drive unit 1 forming a central drive unit of the motor vehicle 2.
[0044] The drive unit 1 has a housing 4 and a differential gear 5 - designed as a bevel gear differential according to the present example - which is located inside the housing-24-2782
[0045] 10
[0046] The differential gear 5 is arranged in Fig. 4. The differential gear 5 is shown in more detail in Fig. 2. It can be seen that a differential cage 6 of the differential gear 5 is rotatably mounted in the housing 4 by means of cage bearings 7 – here by means of two cage bearings 7, which are arranged in the housing 4 at bearing positions F and G. Furthermore, the differential gear 5 has a cage ring gear 8, which is non-rotatably connected to the differential cage 6. In a differential gear chamber 9 (see Fig. 2) of the differential gear 5, differential output gears 10, 11 of the differential gear 5 are rotatably mounted along a main differential axis 12 of the differential gear 5. Transverse to the main differential axis 12, compensating gears 13 of the differential gear 5 are mounted in the differential gear chamber 9, with the compensating gears 13 meshing with both differential output gears 10, 11.Since the drive unit 1 is installed in the vehicle 2 transversely to the longitudinal axis x of the vehicle in this example, the main differential axis 12 and the transverse axis y of the vehicle are arranged parallel to each other.
[0047] Figures 1 and 2 further show a connecting shaft 14 of the drive unit 1, wherein the connecting shaft 14 has two connecting shaft ends 15, 16. The first connecting shaft end 15 is rotationally fixed to the first differential output gear 10 and is thus indirectly supported in the housing 4, namely by means of the cage bearing 7 located in bearing position G. In contrast, the second connecting shaft end 16 is supported by means of a connecting shaft bearing 17 of the drive unit 1 arranged in the housing 4. The connecting shaft bearing 17 is located at bearing position H.
[0048] In the present example, the drive unit 1 also includes an electric traction machine 18, whose rotor-stator unit 19 is arranged in the housing 4. The traction machine 18 forms a traction motor for the motor vehicle 2. A rotor shaft 20 of the traction machine 18 is non-rotatably connected to a rotor of the rotor-stator unit 19, with the rotor shaft 20 and a rotor shaft pinion 21 being coaxially and non-rotatably connected to each other. The rotor shaft 20 is supported in the housing 4 by means of rotor shaft roller bearings 22 of the drive unit arranged in the housing 4, the rotor shaft roller bearings 22 being distributed at bearing positions A, B, and C. As can be seen in Fig. 1, the rotor-stator unit 19 is arranged between the rotor shaft roller bearings 22 of bearing positions A, B, so that the rotor shaft 20, which protrudes from both sides of the rotor-stator unit 19, is supported on both sides of the rotor-stator unit 19. Furthermore, it can be seen from Fig.1 shows that the rotor shaft pinion 21 is arranged between the rotor shaft roller bearings 22 of bearing positions A, C.24-2782.
[0049] 11
[0050] Not shown in the figures are embodiments of the drive unit 1 or the motor vehicle 2 in which the rotor shaft 20 and the cage gear 8 can be directly coupled for torque transmission, for example by (not shown) the rotor shaft pinion 21 and the cage gear meshing directly with each other, whereby the drive unit 1 has exactly one spur gear stage. Figure 1 shows that the rotor shaft 20 and the cage gear 8 are indirectly coupled for torque transmission according to the present example, for instance via an intermediate shaft 23 of the drive unit 1. An intermediate shaft pinion 24 and an intermediate shaft gear 25 are coaxially and rotationally fixed to the intermediate shaft 23.A first spur gear stage 26 of the drive unit 1 is formed by the meshing of the rotor shaft pinion 21 and the intermediate shaft gear 25, and a second spur gear stage 27 of the drive unit 1 is formed by the meshing of the intermediate shaft pinion 24 and the cage ring gear 8. The intermediate shaft 23 is supported in the housing 4 by means of intermediate shaft roller bearings 28 of the drive unit 1, the intermediate shaft roller bearings 28 being arranged in the housing 4 and occupying bearing positions D, E.
[0051] Fig. 1 further shows that the drive unit 1 has two main output shafts 29, 30 which have a common, identical geometry and size, i.e., they are designed as identical parts and are therefore readily interchangeable. A first, here inner, main output shaft end 31 of the first main output shaft 29 is non-rotatably connected to the second differential output gear 11, while a first, here inner, main output shaft end 32 of the second main output shaft 30 is non-rotatably connected to the connecting shaft 14. In this case, the connecting shaft 14 and the second differential output gear 11 each have a splined hub 33 (see Fig. 2), with the inner main output shaft ends 31, 32 each having a splined shaft journal corresponding to the splined hubs 33 to form a respective splined shaft-splined hub connection. Furthermore, Fig.Figure 1 shows that the main output shafts 29, 30 each have two constant velocity joints 34 to allow movement of the main output shafts 29, 30 relative to the differential main axis 12 or to a respective longitudinal center axis 35 of a driven assembly of the drive unit 1 or the motor vehicle 2, which is attached to a respective second, here outer, main output shaft end 36, 37 of the main output shafts 29, 30. In the present example, the two uniform main output shafts 29, 30 are designed as uniform wheel drive shafts, whose outer main output shaft ends 36, 37, i.e., wheel drive shaft ends 36, 37, are rotationally fixed to a respective wheel hub 38 of the motor vehicle 2 or the drive unit 1. A respective motor vehicle wheel 39 of the motor vehicle 2 is rotationally fixed to the respective wheel hub 38. Since the main output shafts 29, 3024-2782.
[0052] 12
[0053] In this example, where the components are uniform and identical, the drive unit 1 is arranged centrally between the wheel hubs 38. The connecting shaft 14 bridges a gap between the first differential output gear 10 and a connection point where the connecting shaft 14 is connected to the second main output shaft 30. The second main output shaft 30 and the connecting shaft 14 form a combined shaft of the drive unit 1, or of the vehicle 2, which comprises the shafts 14 and 30 as partial shafts.
[0054] The drive unit 1 also has a lubrication circuit by means of which a lubricant – in particular a lubricant and coolant, such as oil – can be supplied to the components of the drive unit 1 that require lubrication and / or temperature control. The following components of the drive unit 1 are integrated into the lubrication circuit: the differential gear 5, the cage bearings 7, the rotor shaft bearings 22, the intermediate shaft bearings 28, the single spur gear stage or spur gear stages 26, 27, the rotor-stator unit 19, and peripheral components of the traction machine 18 (for example, an inverter and / or control unit).
[0055] It is particularly noteworthy that the connecting shaft bearing 17—like none of the other bearings 7, 22, 28 in this case—is not installed outside the housing 4 (nor in a bearing seat extending from the outside into an outer circumferential surface of an outer housing wall). Instead, the connecting shaft bearing 17—like all other bearings 7, 22, 28 in this case—is arranged inside the housing 4, that is, within a housing chamber bounded by the outer housing wall. Furthermore, the connecting shaft bearing 17 is not designed as a lifetime grease-lubricated rolling bearing, but is integrated into the lubrication circuit. To ensure that the connecting shaft bearing 17 receives sufficient lubricant / coolant, the connecting shaft 14 is part of the lubrication circuit in this example, as shown in Fig.2 - also includes a fluid conveying unit 40, which is designed to transport lubricant from the differential gear chamber 9 along the differential main axis 12 to the connecting shaft roller bearing 17 during operation of the drive unit 1. The fluid conveying unit 40 is designed to be purely passive, meaning that it is free of a separate working machine for moving a fluid, i.e., free of a motor-driven pump, etc.
[0056] In the present case, the fluid conveying unit 40 has a hollow shaft body 41 of the connecting shaft 14; the connecting shaft 14 is therefore designed as a hollow shaft, namely ent-24-2782
[0057] 13
[0058] along its entire longitudinal extent, as can be seen in Fig. 2. Therefore, the connecting shaft 14 has two end-face hollow shaft openings 42, 43, with the first hollow shaft opening 42 opening into the differential gear chamber 9. A fluid conveying structure 45 is formed along an inner surface 44 of the hollow shaft body 41, which is designed to transport the lubricant along a connecting shaft main axis 46, which coincides with the differential main axis 12, through the hollow shaft body 41 and thus to the connecting shaft roller bearing 17. In this example, the fluid conveying structure 45 has a helical structure 47 that either dips concavely into the inner surface 44 or protrudes convexly from it. The helix structure 47 has a slope direction such that when the connecting shaft 14 is rotated in the preferred direction of rotation, the lubricant is driven towards the connecting shaft roller bearing 17 by means of the helix structure 47.The preferred direction of rotation is associated with a forward direction of travel of the motor vehicle 2. Furthermore, the connecting shaft 14 has one or more fluid-flowable through-openings 48. Each through-opening 48 opens on one side onto the inner surface 44 of the hollow shaft body 41 and on the other side onto the outer circumferential side, i.e., an outer surface 49 of the connecting shaft 14, in this case, the bearing seat of the connecting shaft 14 in which the connecting shaft roller bearing 17 is located, consequently at or in bearing position H. Each through-opening 48 can be arranged obliquely or perpendicularly with respect to the main axis 46 of the connecting shaft.
[0059] During operation of the drive unit 1, the lubricant forms a lubricant mist in the differential gear chamber 9 and from there passes through the first hollow shaft opening 42 and into the material-free area of the hollow shaft body 41, where it condenses on the inner surface 44 as the connecting shaft 14 rotates. Due to the rotating fluid conveying structure 45, in particular the helical structure 47, the lubricant is driven along the main axis 46 of the connecting shaft and, accordingly, along the main axis 12 of the differential towards the connecting shaft roller bearing 17. There, a first portion of the lubricant flows through the through-opening(s) 48 into the bearing seat of the connecting shaft roller bearing 17. A second portion of the lubricant flows out of the second hollow shaft opening 43 and thus reaches and enters the connecting shaft roller bearing 17.Lubricant flowing from the connecting shaft roller bearing 17 is carried away gravimetrically and / or by centrifugal force. The lubricant flowing from the connecting shaft roller bearing 17 thus falls, for example, into a lubricant reservoir or into a lubricant sump of the lubrication circuit. 24-2782.
[0060] 14
[0061] The drive unit 1 and the motor vehicle 2 each offer a possible solution to the task described at the beginning – namely, to minimize friction losses occurring in the drive train of a motor vehicle during ferry operation.24-2782
[0062] 15
[0063] Reference symbol list
[0064] 1 drive unit
[0065] 2 motor vehicles
[0066] 3 drive axle
[0067] 4 cases
[0068] 5 Differential gears
[0069] 6 Differential cage
[0070] 7 cage roller bearings
[0071] 8 cage gear ring
[0072] 9 Differential gear chamber
[0073] 10 Differential output gear
[0074] 11 Differential output gear
[0075] 12 Differential main axis
[0076] 13 Compensating wheel
[0077] 14 Connecting shaft
[0078] 15 Connecting shaft end
[0079] 16 Connecting shaft end
[0080] 17 Connecting shaft roller bearings
[0081] 18 electric traction machines
[0082] 19 Rotor-stator unit
[0083] 20 Rotor shaft
[0084] 21 Rotor shaft pinion
[0085] 22 rotor shaft roller bearings
[0086] 23 Intermediate shaft
[0087] 24 intermediate shaft pinions
[0088] 25 Intermediate shaft gear
[0089] 26 Spur gear stage
[0090] 27 Spur gear stage
[0091] 28 intermediate shaft roller bearings
[0092] 29 Main output shaft
[0093] 30 Main output shaft
[0094] 31 (inner) main output shaft end 24-2782
[0095] 16
[0096] 32 (inner) main output shaft end 33 splined hub
[0097] 34 Constant velocity joint
[0098] 35 Longitudinal center axis
[0099] 36 (outer) main output shaft end 37 (outer) main output shaft end 38 wheel hub
[0100] 39 Motor vehicle wheel
[0101] 40 Fluid conveying unit
[0102] 41 Hollow shaft bodies
[0103] 42 Hollow shaft mouth
[0104] 43 Hollow shaft mouth
[0105] 44 Inner surface area
[0106] 45 Fluid conveying structure
[0107] 46 Main connecting shaft
[0108] 47 Helix structure
[0109] 48 Passage opening
[0110] 49 Outer shell area
[0111] A storage position
[0112] B Storage position
[0113] C Storage position
[0114] D storage position
[0115] E Storage position
[0116] F Storage position
[0117] G Storage position
[0118] H Storage position
Claims
24-2782 17 Patent claims 1. Drive unit (1) for a motor vehicle (2) comprising: - a case (4), - a differential gear (5) whose differential cage (6) is mounted in the housing (4), - a connecting shaft (14) whose first connecting shaft end (15) is rotationally fixed to a first differential output gear (10) of the differential gear (5), and whose second connecting shaft end (16) is mounted by means of a connecting shaft roller bearing (17) of the drive unit (1) arranged in the housing (4), - a lubrication circuit in which the differential gear (5) and the connecting shaft roller bearing (17) are integrated, so that a lubricant can be supplied to them by means of the lubrication circuit in the housing (4), wherein the connecting shaft (14) has a fluid conveying unit (40) which is designed to transport lubricant from a differential gear chamber (9) of the differential gear (5) along a differential main axis (12) of the differential gear (5) to the connecting shaft roller bearing (17) during operation of the drive unit (1).
2. Drive unit (1) according to claim 1, characterized by the fact that The fluid conveying unit (40) has a hollow shaft body (41) of the connecting shaft (14) which opens into the differential gear chamber (9), wherein a fluid conveying structure (45), in particular a helical structure (47), is formed along an inner surface (44) of the hollow shaft body (41), and wherein the connecting shaft (14) has a fluid-flowable through-opening (48) which opens on one side to the inner surface (44) of the hollow shaft body (41) and on the other side on the outer circumferential side, to a bearing seat of the connecting shaft (14) in which the connecting shaft roller bearing (17) is located. 24-2782 18 3. Drive unit (1) according to claim 1 or 2, characterized by an electric traction machine (18) arranged in the housing (4), the rotor shaft (20) of which is supported in the housing (4) by means of rotor shaft roller bearings (22) of the drive unit (1) arranged in the housing (4), wherein both a rotor-stator unit (19) of the traction machine (18) and the rotor shaft roller bearings (22) are integrated into the lubrication circuit.
4. Drive unit (1) according to claim 3, characterized by the fact that exactly one spur gear stage is formed between the rotor shaft (20) and a cage gear ring (8) of the differential gear (5), which is integrated into the lubrication circuit.
5. Drive unit (1) according to one of claims 1 to 3, characterized by an intermediate shaft (23) of the drive unit (1) mounted in the housing (4) by means of intermediate shaft roller bearings (28) arranged in the housing (4), which is non-rotatably connected to an intermediate shaft pinion (24) and to an intermediate shaft wheel (25), so that the drive unit (1) has a spur gear stage (26) in which the intermediate shaft pinion (24) participates and a spur gear stage (27) in which the intermediate shaft wheel (25) participates, wherein one or both of the spur gear stages (26, 27) as well as the intermediate shaft roller bearings (28) are integrated into the lubrication circuit.
6. Drive unit (1) according to one of the preceding claims, characterized by - a first main output shaft (29) which is or can be connected in a rotationally fixed manner to a second differential output gear (11) of the differential gear (5), - a second main output shaft (30) which is or can be connected to the connecting shaft (14) in a rotationally fixed manner, wherein the two main output shafts (29, 30) are designed as identical parts.
7. Motor vehicle (2) with a drive unit (1) designed according to one of the preceding claims.24-2782 19 8. Motor vehicle (2) according to claim 7, characterized by the fact that the drive unit (1) is installed as an axle drive unit transversely to a motor vehicle longitudinal axis (x), wherein the differential main axis (12) and a motor vehicle transverse axis (y) are arranged parallel to each other.