Rolling bearing assembly for a motor vehicle and electrically

Abstract

The invention relates to a rolling bearing assembly (1) for an electrically operable drive train (2) of a motor vehicle (3), comprising a shaft (6) rotatably mounted by means of a first angular contact roller bearing (4) and a second angular contact roller bearing (5), the first angular contact roller bearing (4) comprising a first inner ring (7) and a first outer ring (8), and the second angular contact roller bearing (5) comprising a second inner ring (8) and a second outer ring (8). A first inner ring (7) connected to the shaft (6) for common rotation, between which first cylindrical rolling bodies (10) arranged at a first contact angle (9) are received, and which roll on a first inner ring raceway (11) of the first inner ring (7) and a first outer ring raceway (12) of the first outer ring (8), and the second angular contact roller bearing (5) comprises a second inner ring (13) connected to the shaft (6) for common rotation and a second outer ring (14) between which second cylindrical rolling bodies (16) arranged at a second contact angle (15) are accommodated, and the second cylindrical rolling body rolls on a second inner ring raceway (17) of the second inner ring (13) and on a second outer ring raceway (18) of the second outer ring (14), and wherein the first angular contact roller bearing (4) and the second angular contact roller bearing (5) are axially spaced from each other and are substantially free of axial prestressing force.

Description

Technical Field

[0001] The invention relates to a rolling bearing assembly for an electrically operable drive train of a motor vehicle, the rolling bearing assembly comprising a shaft rotatably mounted by means of a first angular contact roller bearing and a second angular contact roller bearing, wherein the first angular contact roller bearing comprises a first inner ring and a first outer ring, the first inner ring being connected to the shaft for common rotation, a first cylindrical rolling body arranged at a first contact angle being accommodated between the first inner ring and the first outer ring, and the first cylindrical rolling body rolling on the inner ring raceway of the first inner ring and the outer ring raceway of the first outer ring, and the second angular contact roller bearing comprises a second inner ring and a second outer ring, the second inner ring being connected to the shaft for common rotation, a second cylindrical rolling body arranged at a second contact angle being accommodated between the second inner ring and the second outer ring, and the second cylindrical rolling body rolling on the inner ring raceway of the second inner ring and the outer ring raceway of the second outer ring, wherein the first angular contact roller bearing and the second angular contact roller bearing are axially spaced from each other. The invention also relates to an electrically operable drive train of a motor vehicle. Background Art

[0002] Electric motors are increasingly used to drive motor vehicles in order to create an alternative to internal combustion engines that require fossil fuels. Great efforts have been made to improve the suitability of electric drives for everyday use and also to be able to provide users with the driving comfort they are accustomed to. Axial flow machines are increasingly being used as drive units in such automotive applications.

[0003] Axial flux machines are electric generators in which the magnetic flux between the rotor and the stator extends parallel to the axis of rotation of the rotor. Typically, both the stator and the rotor are designed to be predominantly disk-shaped. Axial flux machines are particularly advantageous when the axially available installation space is limited in a given application. This is typically the case, for example, for the electric drive systems for electric vehicles or hybrid vehicles described at the beginning.

[0004] In addition to the reduced axial installation length, another advantage of axial flux machines is their relatively high torque density. The reason for this is that, compared to radial flux machines, for a given installation space, the available air gap area is larger. In addition, compared to conventional machines, less iron volume is required, which has a positive effect on the efficiency of the machine. Typically, axial flux machines comprise at least one stator with windings for generating an axially aligned magnetic field. At least one rotor is equipped, for example, with permanent magnets, the magnetic field of which interacts with the magnetic field of the stator windings in order to generate a drive torque across the air gap.

[0005] The noise emission generated by the drive plays an increasingly important role, especially in the case of hybrid drive concepts or fully electric drive concepts. During the operation of such electric machines for hybrid or fully electric drive trains, for example, high electromagnetic excitations may occur for system-related reasons, which may also lead to acoustic vibrations in the structural components of the electric machine or the drive train. Such acoustic vibrations may also be heard in the interior of the vehicle and are often considered to be disturbing. This is all the more important because such noises are particularly noticeable in the electric operation of the corresponding vehicle and have a negative impact on the otherwise acoustically particularly quiet driving experience.

[0006] Rolling bearing assemblies are often used to support the rotor in such electric machines. For example, floating bearings are often pressed onto the rotor shaft so that they fit tightly with the inner ring of the rolling bearing. The bearing outer ring is often designed to be displaced during operation to compensate for the thermally induced linear expansion of the rotor shaft. In order to create favorable operating conditions between the ball set of the floating bearing and the bearing raceway and to improve the sound quality, the bearing outer ring is regularly prestressed. Prestressed bearings can prevent undesirable acoustic anomalies of the corresponding rolling bearing by creating a clearance degree of freedom for the bearing parts moving against each other.

[0007] In addition to the above-mentioned increasing acoustic requirements on rolling bearing components in electric drive trains in motor vehicles, there is also an increasing need to reduce mechanical power losses, in particular in the bearings of the shafts of the electric motor or the transmission. A reduction in the power losses of these electric motors and / or transmissions has a directly proportional (positive) effect on the power consumption and ultimately on the achievable range of the electric motor vehicle.

[0008] While meeting the requirement to minimize friction losses, the engine torque that then needs to be transmitted through the transmission in electric drive trains has also steadily increased due to the increase in power density achieved. This also increases the loads transmitted by the rolling bearings in such electric drive trains.

[0009] Standard rolling bearings in fixed / floating bearing assemblies are often used for such motors and / or transmissions. These bearings are usually deep groove ball bearings or 3- or 4-point bearings on the fixed bearing side. Although these bearings are very efficient in terms of friction losses, they have significantly lower load ratings compared to roller bearings due to physical reasons (point contact). In order to be able to transmit the required loads, these rolling bearings need to be larger. This means that the motor and / or transmission becomes larger and heavier, and the friction torque also increases significantly again.

[0010] Conversely, rolling bearings with higher load ratings can also be used. These are usually tapered roller bearings in upright assemblies. Due to the line contact, these bearings can carry significantly higher loads and can be made smaller and lighter. This has a positive effect on the engine weight and / or transmission weight and the required installation space. However, upright tapered roller bearings are used in pairs with relatively high preloads. This means that power losses (due to greater friction) are higher than in the case of fixed / floating bearing assemblies.

[0011] Two embodiments of angular contact roller bearings are known from the publications DE 10 2016 214 353 A1 and DE 10 2016 214 355 A1, which basically comprise: an inner bearing ring having an inner raceway arranged on its outer side surface and forming an angle with the bearing rotation axis and an edge delimiting the raceway at its minimum diameter; an outer bearing ring having an outer raceway also arranged on the inner side surface of the bearing ring and forming an angle with the bearing rotation axis and an edge delimiting the raceway at its maximum diameter; and a plurality of cylindrical rolling bodies arranged between the bearing rings and not rolling on the raceways of the bearing rings, which rolling bodies are retained at equal distances from each other in the circumferential direction by a bearing retainer. The outer surface of the inner bearing ring and the inner surface of the outer bearing ring are designed to be coaxially cylindrical on the outside of the raceway according to DE 10 2016 214 353 A1, or are designed to be obliquely opposite to the bearing rotation axis according to DE 10 2016 214 355 A1, and the raceways of the two bearing rings are respectively conically machined into these side surfaces, so that the resulting edge limiting the raceway on one side is thus formed integrally with the bearing ring. Summary of the invention

[0012] The object of the present invention is to avoid or at least reduce the disadvantages known in the prior art and to provide a rolling bearing assembly for an electrically operable drive train of a motor vehicle which allows low friction, high load ratings and acoustically unobtrusive operation. The object of the present invention is also to achieve an electrically operable drive train of a motor vehicle which has particularly low friction losses and a compact design.

[0013] The object is achieved by a rolling bearing assembly for an electrically operable transmission system of a motor vehicle, the rolling bearing assembly comprising a shaft rotatably mounted by means of a first angular contact roller bearing and a second angular contact roller bearing, wherein the first angular contact roller bearing comprises a first inner ring and a first outer ring, the first inner ring being connected to the shaft for common rotation, a first cylindrical rolling body arranged at a first contact angle being accommodated between the first outer ring and the first inner ring, and the first cylindrical rolling body rolling on an inner ring raceway of the first inner ring and an outer ring raceway of the first outer ring, and the second angular contact roller bearing comprises a second inner ring and a second outer ring, the second inner ring being connected to the shaft for common rotation, a second cylindrical rolling body arranged at a second contact angle being accommodated between the second inner ring and the second outer ring, and the second cylindrical rolling body rolling on an inner ring raceway of the first inner ring and an outer ring raceway of the first outer ring Two cylindrical rolling bodies roll on the inner ring raceway of the second inner ring and the outer ring raceway of the second outer ring, wherein the first angular contact roller bearing and the second angular contact roller bearing are axially spaced apart from each other, wherein the first inner ring of the first angular contact roller bearing and the second inner ring of the second angular contact roller bearing are arranged on the shaft in an axially fixed manner, and the first outer ring of the first angular contact roller bearing is axially fixed relative to the first connecting structure of the rolling bearing assembly, and the second outer ring is axially displaceable relative to the second connecting structure, wherein the first inner ring includes a first inner ring edge, the first outer ring includes a first outer ring edge, the second inner ring includes a second inner ring edge, and the second outer ring includes a second outer ring edge, and the first angular contact roller bearing and the second angular contact roller bearing are basically not subjected to axial prestress.

[0014] This offers the advantage that the rolling bearing assembly has a high load carrying capacity and service life compared to ball bearing solutions and has low friction compared to tapered roller bearing solutions. The basic idea of ​​the invention is to operate the angular contact roller bearings without preload or with only a slight preload. This means that the preload forces acting on the bearings are significantly reduced and the friction torque is significantly reduced. At the same time, these angular contact roller bearings can still transmit high loads due to the line contact.

[0015] The additional inner ring rim on the inner ring of the angular contact roller bearing ensures that the internal axial clearance of the angular contact roller bearing is limited and thereby prevents the service life of the angular contact roller bearing from being significantly shortened. However, the advantages of the bearing, such as load carrying capacity and friction, are retained.

[0016] One possible field of application for the rolling bearing assembly according to the invention is an electrically operated drive train of a motor vehicle, for example an electric motor or a special hybrid transmission, since the mounting conditions in a corresponding housing allow the upright angular contact roller bearing to be assembled floatingly or slightly prestressed without exerting additional constraining forces on the bearing.

[0017] First, the individual elements of the claimed subject matter of the present invention are explained in the order in which the elements are mentioned in the claims, and thereafter particularly preferred embodiments of the claimed subject matter of the present invention are described.

[0018] The rolling bearing assembly according to the invention comprises two angular contact roller bearings axially spaced apart from each other. In order to support the shaft in a rotatable manner relative to the connection structure, each of the angular contact roller bearings has an inner ring, an outer ring and a cylindrical rolling body arranged between these rings in a rolling manner. Between these three main components - inner ring, outer ring and rolling body - rolling friction usually occurs mainly in the angular contact roller bearing. Since the cylindrical rolling bodies in the inner ring and outer ring can preferably roll on a hardened steel surface with optimized lubrication, the rolling friction of such a bearing is relatively low.

[0019] The inner ring can in particular connect a shaft accommodating an angular contact roller bearing to the angular contact roller bearing or a cylindrical rolling body. In particular, the shaft can be connected to the side of the lateral surface of the inner ring facing the shaft, wherein the rolling body of the angular contact roller bearing rolls on the inner ring raceway opposite to the lateral surface. The inner ring can be made of a metallic material and / or a ceramic material. In principle, it is conceivable to design the inner ring as one piece or multiple pieces, in particular two pieces.

[0020] The inner ring may have an inner ring recess. In particular, a covering gasket, a sealing gasket and / or a seal may be arranged in the inner ring recess, in particular in a force-fitting and / or form-fitting manner. Preferably, the inner ring recess is formed as a circumferential groove in the inner ring.

[0021] The outer ring can in particular connect the connection structure to the angular contact roller bearing or the rolling body. In particular, the connection structure can be connected to the side of the lateral surface of the inner ring facing the bearing, wherein the cylindrical rolling body of the angular contact roller bearing rolls on the outer ring raceway opposite to the lateral surface. The outer ring can be made of a metallic material and / or a ceramic material. In principle, it is conceivable to design the outer ring as one piece or multiple pieces, in particular two pieces.

[0022] The outer ring may have an outer ring recess. In particular, a covering gasket, a sealing gasket and / or a seal may be arranged in the outer ring recess, in particular in a force-fitting and / or form-fitting manner. Preferably, the outer ring recess is formed as a circumferential groove in the outer ring.

[0023] The rolling body has the shape of a roller. The rolling body rolls on the raceway of the angular contact roller bearing and has the task of transferring the forces acting on the angular contact roller bearing from the outer ring to the inner ring and from the inner ring to the outer ring. The roller-like rolling body can be selected, for example, from symmetrical spherical rollers, asymmetrical spherical rollers, cylindrical rollers, needle rollers and / or tapered rollers.

[0024] The rolling body can roll in the rolling bearing, in particular on the inner ring raceway of the inner ring. For this purpose, the surface of the inner ring raceway can advantageously be designed to be wear-resistant, for example by means of corresponding surface treatment methods and / or by applying corresponding additional material layers. The inner ring raceway can be designed to be flat or profiled. For example, the profiled design of the inner ring raceway can be used to guide the rolling body on the inner ring raceway. On the other hand, the flat configuration of the inner ring raceway can, for example, allow a certain axial displacement of the rolling body on the inner ring raceway.

[0025] The rolling body can roll in the rolling bearing, in particular on the outer ring raceway of the outer ring. For this purpose, the surface of the outer ring raceway can advantageously be designed to be quite wear-resistant, for example by means of a corresponding surface treatment method and / or by applying a corresponding additional material layer.

[0026] The outer ring raceway can be designed to be flat or contoured. For example, the contoured design of the outer ring raceway can be used to guide the rolling bodies on the outer ring raceway. On the other hand, the flat configuration of the outer ring raceway can, for example, allow a certain axial displacement of the rolling bodies on the outer ring raceway.

[0027] The rolling elements can be guided and spaced apart in a cage or by rolling element spacers. In principle, it is also conceivable to design a rolling bearing without a cage, which is also called a full-complement rolling bearing. In a full-complement rolling bearing, adjacent rolling elements can be in contact with one another.

[0028] The rolling bearing may have a cage, wherein the cage guides the rolling bodies. The cage is designed such that the rolling body balls and / or rolling body rollers are spaced apart from one another, so that, for example, friction and thermal growth of the rolling bodies are kept as low as possible. Furthermore, the cage holds the rolling body balls and / or rolling body rollers at a fixed distance from one another during rolling, whereby a uniform load distribution can be achieved. The cage may be manufactured in one piece or in multiple pieces.

[0029] Rolling bearings may have at least one seal in order to prevent lubricant from escaping from the rolling bearing or to prevent dust or moisture from entering the rolling bearing. For this purpose, the seals used may be provided with one or more sealing lips which can bear against components of the rolling bearing. The seals are designed such that, on the one hand, they seal the bearing as long as possible throughout its service life and, on the other hand, the friction level caused by the continuous sealing is not too high.

[0030] Advantageous embodiments of the invention are specified in the dependent claims. The features listed individually in the dependent claims can be combined with one another in a technically meaningful manner and can define further embodiments of the invention. In addition, the features indicated in the claims are described and explained in more detail in the description, wherein further preferred embodiments of the invention are shown.

[0031] According to an advantageous embodiment of the invention, it can be provided that a spacing sleeve (intermediate ring / spacer) or a raised shaft shoulder (raised shaft section) is arranged axially between the first inner ring and the second inner ring on the shaft, on which the first inner ring and the second inner ring rest. The advantage of this design is that the inner rings are arranged at a fixed distance from each other. This can be achieved by means of a fixing screw fastened on the shaft, which presses the inner ring from the outside against the spacing sleeve / intermediate ring or the raised shaft shoulder serving as an axial bearing element.

[0032] According to another preferred improvement of the present invention, it can also be provided that the first outer ring is arranged with clearance in the radial direction relative to the first connection structure, and / or the second outer ring is arranged with clearance in the radial direction relative to the second connection structure. This allows the material of the connection structure to have a higher thermal expansion than the material of the outer ring.

[0033] The connection structure can be, for example, an engine or transmission housing. It can also be advantageous to form the first connection structure and the second connection structure in one piece, in particular in one piece.

[0034] Furthermore, according to a likewise advantageous embodiment of the invention, it can be provided that the first outer ring rests axially on the first fixing element. The advantageous effect of this design is based on the fact that a very precise axial guidance of transmission components such as gears can be ensured during operation.

[0035] According to another particularly preferred embodiment of the present invention, it can be provided that the first fixing element is axially fixed relative to the first connecting structure. In this case, the first fixing element can be designed, for example, as a fixing ring or the like, which is inserted into the first connecting structure. In principle, it is also conceivable that the first fixing element is formed integrally, in particular integrally, with the first connecting structure.

[0036] Furthermore, the invention can be further developed so that the second outer ring is positioned with axial play relative to the second fixing element. The advantage of this design is that a slight axial floating operation of the rolling bearing can be envisaged. Eliminating axial loads means that the overall load on the rolling bearing is lower, which can be associated with lower friction losses.

[0037] In an equally preferred embodiment of the invention, the second fixing element is axially fixed relative to the second connecting structure. In this case, the second fixing element can also be designed, for example, as a fixing ring or the like, which is inserted into the second connecting structure. In principle, it is also conceivable that the second fixing element is formed integrally, in particular integrally, with the second connecting structure.

[0038] It can also be advantageous that the invention is further developed so that the first cylindrical rolling body and / or the second cylindrical rolling body are designed as cylindrical rollers or tapered rollers. The advantages that can be achieved in this way are that the tapered roller operates almost without sliding due to kinematically pure rolling, and the cylindrical roller is easier to manufacture.

[0039] Furthermore, the first inner ring rim and / or the second inner ring rim can be formed as one piece, in particular integrally, with the first inner ring or the second inner ring. Alternatively, it is of course also conceivable that the first inner ring rim and / or the second inner ring rim are each designed as a separate component and connected to the first inner ring or the second inner ring.

[0040] Similar to the inner ring, the first outer ring edge and / or the second outer ring edge can also be formed as one piece, especially integrally with the first outer ring or the second outer ring. Alternatively, it is of course also conceivable that the first outer ring edge and / or the second outer ring edge are each designed as a separate component and connected to the first outer ring or the second outer ring.

[0041] According to another preferred embodiment of the inventive subject matter, it can be provided that the first angular contact roller bearing and the second angular contact roller bearing are arranged in an O-configuration. In principle, the first angular contact roller bearing and the second angular contact roller bearing can also be arranged in an X-configuration.

[0042] The objects of the invention are also achieved by an electrically operable drive train of a motor vehicle, comprising an electric motor and a transmission assembly connected to the electric motor, wherein the electric motor comprises a stator and a rotor arranged to be rotatable relative to the stator, wherein the shaft of the rotor and / or the transmission assembly is mounted by means of a rolling bearing assembly according to one of the preceding claims.

[0043] The electrically operable drive train may include an electric machine and a transmission assembly coupled to the electric machine. The transmission assembly and the electric machine may also form a structural unit. The structural unit may be formed, for example, by means of a drive train housing in which the transmission assembly and the electric machine are accommodated together.

[0044] The electric machine preferably has a motor housing and / or the transmission assembly has a transmission housing, wherein the assembly can then be realized by fastening the transmission assembly relative to the electric machine.

[0045] The transmission housing is a housing for accommodating the transmission. The task of the transmission housing is to guide the existing shaft via bearings and to provide the wheel (cam disc, if applicable) with the required degrees of freedom under all loads without hindering the rotation and possible path movement of the wheel, as well as to absorb the bearing forces and support torques. The transmission housing can be designed as a single shell or multiple shells, i.e. inseparable or separate. In particular, the transmission housing should be able to suppress noise and vibrations and to absorb hydraulic fluids safely. The transmission housing is preferably formed from a metal material, particularly preferably from aluminum, gray cast iron or cast steel, in particular by means of a one-shot forming process, such as casting or die casting.

[0046] The motor housing encloses the electric motor. The motor housing may also accommodate control electronics and power electronics. The motor housing may also be part of a cooling system for the electric motor, and the motor housing may be designed so that hydraulic fluid can be supplied to the electric motor via the motor housing and / or heat can be dissipated to the outside via the housing surface. In addition, the motor housing protects the electric motor and any electronics that may be present from external influences. The motor housing may in particular be formed from a metal material. Advantageously, the motor housing may be formed from a metal casting material such as die-cast aluminum, die-cast magnesium, gray cast iron or cast steel. The motor housing may preferably be designed in multiple parts.

[0047] The electric motor is used to convert electrical energy into mechanical energy and / or convert mechanical energy into electrical energy, and the electric motor generally includes a fixed part called a stator, a bracket or an armature and a part called a rotor or a wheel which is arranged in a movable manner, in particular in a rotatable manner, relative to the fixed part.

[0048] In particular, the electric machine is dimensioned such that a vehicle speed of more than 50 km / h, preferably more than 80 km / h, and in particular more than 100 km / h can be achieved. The electric motor particularly preferably has an output of more than 30 kW, preferably more than 50 kW, and in particular more than 70 kW. Furthermore, it is preferred that the electric machine provides a speed of more than 5000 rpm, particularly preferably more than 10000 rpm, very particularly preferably more than 12500 rpm.

[0049] For the purposes of this application, a motor vehicle is a land vehicle that moves by machine power without the constraints of railway tracks. The motor vehicle may for example be selected from a passenger car, a truck, a scooter, a light motor vehicle, a motorcycle, a bus / coach or a tractor. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Without limiting the general inventive concept, the invention is explained in more detail below with reference to the accompanying drawings.

[0051] In the attached picture:

[0052] Figure 1 shows an axial cross-sectional view of a first rolling bearing assembly for an electrically operable drive train of a motor vehicle,

[0053] Figure 2 shows an axial cross-sectional view of a second rolling bearing assembly for an electrically operable drive train of a motor vehicle,

[0054] Figure 3 A fully electric motor vehicle and a hybrid motor vehicle are shown in schematic block diagrams. DETAILED DESCRIPTION

[0055] Figure 1 A rolling bearing assembly 1 for an electrically operable drive train 2 of a motor vehicle 3 is shown, comprising a shaft 6 which is rotatably mounted by means of a first angular contact roller bearing 4 and a second angular contact roller bearing 5 .

[0056] The first angular contact roller bearing 4 includes a first inner ring 7 and a first outer ring 8, the first inner ring is connected to the shaft 6 for common rotation, and a first cylindrical rolling body 10 arranged at a first contact angle 9 is accommodated between the first inner ring and the first outer ring, and the first cylindrical rolling body rolls on the inner ring raceway 11 of the first inner ring 7 and the outer ring raceway 12 of the first outer ring 8.

[0057] Similar to the first angular contact roller bearing, the second angular contact roller bearing 5 includes a second inner ring 13 and a second outer ring 14, which is connected to the shaft 6 for common rotation, and a second cylindrical rolling body 16 arranged at a second contact angle 15 is accommodated between the second inner ring and the second outer ring, and the second cylindrical rolling body rolls on the inner ring raceway 17 of the second inner ring 13 and the outer ring raceway 18 of the second outer ring 14.

[0058] The first cylindrical rolling body 10 and the second cylindrical rolling body 16 are designed as cylindrical rollers or tapered rollers. Figure 1 It can be clearly seen in FIG. 2 that the two angular contact roller bearings 4 , 5 are essentially identical in design, but are rotated 180° relative to each other and are arranged axially spaced apart from each other on the shaft 6 .

[0059] The first inner ring 7 of the first angular contact roller bearing 4 and the second inner ring 13 of the second angular contact roller bearing 5 are arranged in an axially fixed manner on the shaft 6. The first outer ring 8 of the first angular contact roller bearing 4 is axially fixed relative to the first connection structure 19 of the rolling bearing assembly 1. Figure 1 The fixing of these rings is also indicated by the unmarked circles in the corresponding circles. It can be seen that the first angular contact roller bearing 4 is designed as a fixed bearing and the second angular contact roller bearing 5 is designed as a floating bearing. The second outer ring 14 can be axially displaced relative to the second connection structure 20.

[0060] The first outer ring 8 rests axially on the first fixing element 26 and is thus axially fixed on one side. The first fixing element 26 is axially fixed relative to the first connection structure 19. The inner rings 7, 14 can be fixed axially fixed on the shaft 6, for example by means of a press fit. A spacer sleeve 25 is arranged axially between the first inner ring 7 and the second inner ring 13 on the shaft 6, on which the first inner ring 7 and the second inner ring 13 rest.

[0061] In the embodiment shown, the spacing sleeve 25 is an intermediate ring or a spacer on the shaft 6. Of course, it is also possible to form the spacing sleeve 25 in one piece with the shaft 6, so that a radially raised shoulder is formed, on which the inner rings 7, 13 rest. The inner rings 7, 13 are arranged at a fixed distance from each other. This can be achieved, for example, by means of a set screw fastened to the shaft 6, which presses the inner rings 7, 13 from the outside against the spacing sleeve 25 or the raised shoulder serving as an axial bearing element.

[0062] The first angular contact roller bearing 4 and the second angular contact roller bearing 5 are substantially not subjected to axial prestress.

[0063] In addition, you can Figure 1 It can be clearly seen in the figure that the first inner ring 7 comprises a first inner ring rim 21, the first outer ring 8 comprises a first outer ring rim 22, the second inner ring 13 comprises a second inner ring rim 23, and the second outer ring 14 comprises a second outer ring rim 24. The first cylindrical rolling body 10 does not run on the first inner ring rim 21, which is due to the geometry of the first angular contact roller bearing 4.

[0064] Depending on the operating temperature and the initial preload applied to the fixing element 26, the cylindrical rolling body 10 designed as a tapered roller presses itself against the outer ring rim 22 due to the tapering effect indicated by the solid black arrow. In certain (rather low load) situations, contact may occur with the inner ring rim 21. This does not significantly impair the efficiency of the angular contact roller bearings 4, 5, but on the other hand can have a positive effect on preventing the rollers from sinking.

[0065] The first outer ring 8 is arranged with play in the radial direction relative to the first connection structure 19 , and the second outer ring 14 is arranged with play in the radial direction relative to the second connection structure 20 , which can be easily understood from the annular gaps between the outer rings 8 , 14 and the connection structures 19 , 20 shown in the figure.

[0066] The second outer ring 14 is positioned with axial play relative to the second fixing element 27 , wherein the second fixing element 27 itself is axially fixed relative to the second connecting structure 20 .

[0067] exist Figure 1In the exemplary embodiment of the present invention, the first angular contact roller bearing 4 and the second angular contact roller bearing 5 are arranged in an O-shaped configuration. Figure 2 In the exemplary embodiment of FIG. 1 , the first angular contact roller bearing 4 and the second angular contact roller bearing 5 are shown as an X-shaped configuration. Figure 2 In this embodiment, the spacer sleeve 25 is formed integrally with the connection structure 19, wherein the outer rings 8, 14 are axially supported on the spacer sleeve 25. The inner rings 7, 13 are axially supported on the fixing elements 26 and 27, respectively.

[0068] Figure 3 Two embodiments of an electrically operable drive train 2 of a motor vehicle 3 are shown, each comprising an electric machine 28 and a transmission assembly 29 coupled to the electric machine 28, wherein the electric machine 28 has a stator 30 and a rotor 31 arranged to be rotatable relative to the stator 30. Here, the shaft of the rotor 31 and / or the transmission assembly 29 is connected by means of a transmission assembly such as Figure 1 or Figure 2 The rolling bearing assembly 1 shown in FIG. 1 is installed.

[0069] The terms "radial", "axial", "tangential" and "circumferential direction" used in this application always refer to the axis of rotation R of the shaft 6. The terms "left", "right", "above", "below", "above", and "below" are used here only to clarify the illustrated area currently described in the text. Later embodiments of the present invention may also be arranged in different ways. The present invention is also not limited to the embodiments shown in the accompanying drawings. Therefore, the above description should not be regarded as restrictive, but as illustrative. The attached claims should be understood to mean that the stated features are present in at least one embodiment of the present invention. This does not exclude the presence of other features. In the case where the claims and the above description define a "first" feature and a "second" feature, this naming is used to distinguish between two features of the same type without limiting the order of priority.

[0070] Reference numerals list

[0071] 1 Rolling bearing assembly

[0072] 2 Drivetrain

[0073] 3 Motor vehicles

[0074] 4 Angular contact roller bearings

[0075] 5 Angular contact roller bearings

[0076] 6 Axis

[0077] 7 Inner circle

[0078] 8 Outer ring

[0079] 9 Contact Angle

[0080] 10 Cylindrical rolling body

[0081] 11 Inner ring raceway

[0082] 12 Outer ring raceway

[0083] 13 Inner Circle

[0084] 14 Outer ring

[0085] 15 Contact Angle

[0086] 16 Cylindrical rolling body

[0087] 17 Inner ring raceway

[0088] 18 Outer ring raceway

[0089] 19 Connection structure

[0090] 20 Connection structure

[0091] 21 Inner edge

[0092] 22 Outer ring edge

[0093] 23 Inner edge

[0094] 24 Outer ring edge

[0095] 25 Spacer sleeve

[0096] 26 Fixing elements

[0097] 27 Fixing elements

[0098] 28 Motor

[0099] 29 Transmission components

[0100] 30 Stator

[0101] 31 Rotor

Claims

1. A rolling bearing assembly (1) for an electrically operable drive train (2) of a motor vehicle (3), comprising a shaft (6) rotatably mounted by means of a first angular contact roller bearing (4) and a second angular contact roller bearing (5), The first angular contact roller bearing (4) comprises a first inner ring (7) and a first outer ring (8), the first inner ring being connected to the shaft (6) for common rotation, a first cylindrical rolling body (10) being accommodated between the first inner ring and the first outer ring at a first contact angle (9), and the first cylindrical rolling body rolling on an inner ring raceway (11) of the first inner ring (7) and an outer ring raceway (12) of the first outer ring (8), and The second angular contact roller bearing (5) comprises a second inner ring (13) and a second outer ring (14), the second inner ring being connected to the shaft (6) for common rotation, a second cylindrical rolling body (16) being accommodated between the second inner ring and the second outer ring at a second contact angle (15), and the second cylindrical rolling body rolling on an inner ring raceway (17) of the second inner ring (13) and an outer ring raceway (18) of the second outer ring (14), The first angular contact roller bearing (4) and the second angular contact roller bearing (5) are axially spaced apart from each other, It is characterized in that The first inner ring (7) of the first angular contact roller bearing (4) and the second inner ring (13) of the second angular contact roller bearing (5) are arranged on the shaft (6) in an axially fixed manner, and the first outer ring (8) of the first angular contact roller bearing (4) is axially fixed relative to the first connecting structure (19) of the rolling bearing assembly (1), and The second outer ring (14) is axially displaceable relative to the second connecting structure (20), wherein: The first inner ring (7) includes a first inner ring edge (21), the first outer ring (8) includes a first outer ring edge (22), the second inner ring (13) includes a second inner ring edge (23), and the second outer ring (14) includes a second outer ring edge (24), and The first angular contact roller bearing (4) and the second angular contact roller bearing (5) are substantially free from axial prestress.

2. The rolling bearing assembly (1) according to claim 1, It is characterized in that A spacer sleeve (25) is axially arranged between the first inner ring (7) and the second inner ring (13) on the shaft (6), and the first inner ring (7) and the second inner ring (13) rest on the spacer sleeve.

3. Rolling bearing assembly (1) according to any one of the preceding claims, It is characterized in that The first outer ring (8) is arranged with play in a radial direction relative to the first connection structure (19), and / or the second outer ring (14) is arranged with play in the radial direction relative to the second connection structure (20).

4. Rolling bearing assembly (1) according to any one of the preceding claims, It is characterized in that The first outer ring (8) rests axially on a first fixing element (26).

5. The rolling bearing assembly (1) according to claim 4, It is characterized in that The first fixing element (26) is axially fixed relative to the first connecting structure (19).

6. Rolling bearing assembly (1) according to any one of the preceding claims, It is characterized in that The second outer ring (14) is positioned with axial play relative to the second fixing element (27).

7. The rolling bearing assembly (1) according to claim 6, It is characterized in that The second fixing element (27) is axially fixed relative to the second connecting structure (20).

8. Rolling bearing assembly (1) according to any one of the preceding claims, It is characterized in that The first cylindrical rolling body (10) and / or the second cylindrical rolling body (16) are designed as cylindrical rollers or tapered rollers.

9. Rolling bearing assembly (1) according to any one of the preceding claims, It is characterized in that The first angular contact roller bearing (4) and the second angular contact roller bearing (5) are arranged in an O-shaped configuration.

10. An electrically operable drive train (2) of a motor vehicle (3), comprising an electric motor (28) and a transmission assembly (29) connected to the electric motor (28), the electric motor (28) comprising a stator (30) and a rotor (31) arranged to be rotatable relative to the stator (30), the shaft of the rotor (31) and / or the transmission assembly (29) being mounted by means of a rolling bearing assembly (1) according to one of the preceding claims.

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