Rotor carrier for an electric machine

Abstract

Rotor carrier for a rotor (2.2) of an electrical machine (2), wherein the rotor carrier comprises a tubular base body (13), wherein the base body (13) has means on an outer circumferential surface facing the rotor (2.2) which enable a positive and / or non-positive connection between the base body (13) and the rotor (2.2), and wherein a connecting element (14) has an axial section which runs coaxially to the base body (13), and wherein receptacles for parts of a coupling (7) are provided on an inner circumferential surface of the axial section facing away from the base body (13), characterized in that the connecting element (14) connects the base body (13) to a hub (4), that the axial section of the connecting element (14) extends over part of the axial length of the base body (13), and that the connecting element (14) has a flange region adjoining the axial section.

Description

[0001] The invention relates to a rotor carrier for an electric machine, in particular in a hybrid drive train of a vehicle.

[0002] In addition to solid rotors, ring-shaped rotors arranged around a rotational axis are also known in the prior art for electrical machines. For example, DE 10 2016 215 595 A1 discloses that a rotor core is mounted on a sleeve, and the sleeve is connected to the rotational axis at one end. This prior art is reflected in the preamble of claim 1.

[0003] Further examples of the state of the art with ring-shaped rotors are known, for example, from DE 10 2009 059 944 A1 or DE 10 2016 216 651 A1.

[0004] The object of the invention is to provide an alternative to the prior art, which has better support of the rotor and optimized use of installation space, as well as being simple and cost-effective to manufacture.

[0005] The problem is solved by the features of the independent patent claims. Advantageous embodiments emerge from the subclaims, the description, and the figures.

[0006] According to the invention, a rotor carrier for a rotor of an electrical machine, wherein the rotor carrier comprises a tubular base body, wherein the base body has means on an outer circumferential surface facing the rotor which enable a positive and / or non-positive connection between the base body and the rotor, and wherein the base body is connected to a hub by a connecting element, characterized in that the connecting element has an axial section which extends over part of the axial length of the base body and runs coaxially thereto, that receptacles for parts of a coupling are provided on an inner circumferential surface of the axial section facing away from the base body, and that the connecting element has a flange region adjoining the axial section.To connect the base body and the rotor, for example, a profile is provided on the base body, in which elevations and / or depressions are provided at least on the outer circumferential surface, which interact with corresponding counterparts on the inner surface of the rotor to create a positive connection. Alternatively or cumulatively, elevations or depressions in the circumferential direction, such as steps or annular grooves, can also be provided, which can be used for a positive or non-positive connection. Instead of a positive connection, a non-positive connection can also be provided, in which the rotor is connected to the base body via clamping devices, screw connections, rivets or the like. In principle, material-to-material connections are also possible, in which the rotor is welded to the base body.Combinations are also possible in which different types of connections are used, for example to represent or secure connections in different directions.

[0007] The base body is connected to a hub by a connecting element to transmit torque. In this context, a hub refers to and includes not only a conventional hub mounted on a shaft, but also a direct connection to a shaft or a connection to a subsequent component in the drive train, such as a converter housing.

[0008] The connection to the hub is made via a flange area of ​​the connecting element, which is shaped accordingly in the radial direction.

[0009] On the inner circumferential surface of the axial section of the connecting element, which runs coaxially to the base body, receptacles for clutch components are provided. These components are preferably grooves or elevations in the axial direction that serve as receptacles for the plates of a multi-plate clutch. The connecting element thus simultaneously represents the outer plate carrier of a clutch. The clutch can, for example, separate the power flow from or to an internal combustion engine located upstream in the drive train.

[0010] Embodiments of a rotor carrier are characterized in that the axial section of the connecting element has an axial length in the range of 25% to 75% of the axial length of the base body. The coaxial region of the connecting element is shorter than the base body. This allows, on the one hand, the flange region to be positioned closer to the center of the rotor in the axial direction, thereby reducing the force flow and the load on the connecting element. On the other hand, this allows overall axial installation space to be saved, since subsequent components on an output shaft can be provided at least partially within the rotor projecting beyond the connecting element.

[0011] The length of the axial section should be between one and three-quarters, i.e., 25% to 75%, of the length of the base body. This allows the flange area to be positioned close enough to the center of the rotor, providing sufficient space for the coupling components. A secure connection to the base body can also be established.

[0012] Another advantageous aspect is that, if necessary, identical connecting elements can be used for different base bodies of different rotors, which is advantageous in terms of manufacturing and costs. This effect also applies analogously to the base body, since, depending on the drive train, different connecting elements can be used to install identical base bodies.

[0013] Rotor carriers according to embodiments are characterized in that the connecting element has a connection region at the axial end opposite the flange region, and that the connection region is connected to the base body. The connection region can be formed by an end face, an outwardly or inwardly extending collar, or an edge region of the outer circumferential surface. Accordingly, the connection region can be brought into contact with and connected, preferably by welding or riveting, a corresponding region of the base body, such as a shoulder, an end face, an inwardly or outwardly extending collar, or a region of the inner circumferential surface.

[0014] The connection area is provided adjacent to the axial section, but can also be arranged overlapping it, for example as a circumferential surface.

[0015] Preferred embodiments of a rotor carrier are characterized in that the connection area is connected to an axial end of the base body, and that the axial section runs coaxially within the base body. An arrangement at the axial end simplifies positioning and the establishment of the connection. A coaxial extension improves stability.

[0016] Embodiments of a rotor carrier are characterized by the axial section being in contact with the base body. Contact between the connecting element and the base body along the axial section can further improve the stability of the rotor carrier. Furthermore, the contact area can also be used as a connection area or part of the connection area.

[0017] Rotor carriers according to embodiments are characterized in that the base body and / or the connecting element have a cross-section that is modified in the radial direction at at least one point along the axial extent in order to form a stop for positioning the base body and the connecting element relative to each other. In order to be able to easily and quickly determine the position during assembly of the base body and the connecting element, the use of circumferential shoulders or projections is advantageous, as these can form stops in the axial direction against which the corresponding counterpart can be pushed.

[0018] Embodiments of a rotor carrier are characterized in that the connection between the base body and the connecting element is positively connected at least in one direction. For example, a positive connection can be created between the base body and the connecting element by means of the aforementioned steps or a profiling of the cross-section. For production from sheet metal or tubular sections, a relatively uniform wall thickness can be maintained if, for example, a depression is provided on the inner surface at a point on the circumference with a raised outer surface. In addition to weight savings, lower manufacturing costs can also be achieved compared to machining a solid blank.

[0019] Embodiments of a rotor carrier are characterized in that the connection between the base body and the connecting element is materially bonded in at least one direction. After the base body and the connecting element are positioned relative to each other, the parts are advantageously welded together, thereby achieving a strong, simple, and cost-effective connection.

[0020] Preferred embodiments of a rotor carrier are characterized in that a weld seam between the base body and the connecting element runs coaxially between two circumferential surfaces or between two end faces. The weld seam runs along the contact surfaces between the base body and the connecting element or the connection area of ​​the connecting element. Depending on the design of the components, the weld seams can run either along adjacent end faces at an axial end or along a circumferential surface on the inner or outer circumference. Especially in overlapping areas, it is also possible for the weld seam to be formed by several spot welds distributed over the circumference.

[0021] Embodiments of a rotor carrier are characterized in that the flange area is directly connected to a converter housing, or that the flange area extends in the radial direction and is connected to a hub. In a drive train with a downstream torque converter, with an appropriate design of the converter housing, the connecting element, more precisely the flange area, can be connected directly to the converter housing. The connection can preferably be made on a circumferential surface of the converter housing, whereby the flange area can be made short and the greatest savings in axial installation space can be achieved. However, a connection to a circumferential surface of the converter housing requires high manufacturing and assembly costs. It is also possible to make the flange area longer in order to extend it further inwards in the radial direction.The flange area can then be connected, for example, to an end wall of the converter housing or to a separately designed hub. By connecting to the end wall of the converter housing, the required axial space can be kept to a minimum while allowing for relatively simple assembly. A separate hub, which is pushed onto an output shaft, allows for easier preparation and assembly of assemblies and, if necessary, improved standardization, since any standardized rotor carriers can be connected to other, possibly also standardized, components via the model-specific hub.

[0022] Rotor carriers according to embodiments are characterized in that the base body and / or the connecting element are longer than the rotor at least at one axial end. The length refers in particular to the length of the rotor's laminated core. A rotor carrier that protrudes beyond the rotor can, on the one hand, improve the positioning of the components through shoulders, projections, and the like, and, on the other hand, improve cooling with an appropriate design. Furthermore, the protruding rotor carrier, or more precisely the protruding base body and / or connecting element, provides a certain degree of mechanical protection for the rotor. The protruding rotor arm can also be used in particular for balancing the rotor by attaching balancing weights to the protruding rotor arm or by removing material locally.

[0023] Embodiments of a rotor carrier are characterized in that the base body and / or the connecting element have at least one recess extending radially through for the passage of oil. At least one recess is provided to guide oil for lubrication and cooling from the inside to the outside. This recess is preferably arranged in the region of an axial end of the laminated core or opening into an oil channel formed between the rotor carrier and the laminated core.

[0024] Preferred embodiments of a rotor carrier are characterized in that a plurality of recesses are arranged distributed over the circumference. For a more even distribution of the oil and to avoid imbalance, a plurality of recesses are distributed, preferably symmetrically, over the circumference. In this case, a plurality of recesses can also be provided at different axial positions, which can, for example, improve cooling on both sides. In addition to the recesses, guide elements can also be provided on the connecting element or base body in order to guide oil impinging from the inside to the recesses or to be able to release it in a targeted manner to the outside. These guide elements can be designed as channels, annular grooves or depressions inclined towards the recess, or also as raised struts, projections or steps.These guide elements can, if necessary, also serve as receptacles for the parts of a coupling or can be used to create a positive connection between the connecting element and the base body.

[0025] Embodiments of a rotor carrier are characterized by the fact that the base body is made from a formed tube section. Since the basic shape of the base body is given in a tube section, a base body can advantageously be produced from a tube section, which is formed into a base body through appropriate forming and / or processing steps. Alternatively, the base body can also be formed from sheet metal.

[0026] Embodiments of a rotor carrier are characterized by the fact that the connecting element is made of a formed sheet metal. The connecting element, including the connection area and flange area, can advantageously be manufactured from a sheet metal using appropriate forming, pressing, or flow-forming processes.

[0027] A further aspect of the invention is a hybrid module comprising an input shaft, a clutch, an electric motor, a torque converter, and an output shaft, which is characterized in that a rotor carrier according to one of the described embodiments is provided. This allows the described advantages regarding axial installation space and the like to be utilized in a hybrid module.

[0028] The embodiments are not limited to the above examples and can be achieved through further corresponding configurations. The features of the embodiments can be combined with one another in any way.

[0029] The invention is explained in more detail below with reference to the figures. Identical or similar elements are designated by identical reference numerals. The figures show in detail: Fig. 1 shows a schematic section of an embodiment of a hybrid module. Fig. 2 shows a schematic section of an embodiment of a hybrid module. Fig. 3 shows an enlarged section of Fig. 2. Fig. 4 shows a detailed view of a base body with a connecting element. Fig. 5 shows a partial area of ​​a schematic section of a hybrid module in the area of ​​the rotor in one embodiment. Fig. 6 shows a partial area of ​​a schematic section of a hybrid module in the area of ​​the rotor in one embodiment. Fig. 7 shows a partial area of ​​a schematic section of a hybrid module in the area of ​​the rotor in one embodiment.

[0030] Fig. Figure 1 shows a hybrid module according to an exemplary embodiment in a schematic sectional view, with one half omitted for symmetry. The hybrid module comprises a housing (1) within which an electric machine (2) is arranged, having a stator (2.1) that is rotationally fixed relative to the housing (1) and a rotatable rotor (2.2).

[0031] The hybrid module has a torque converter (5). The converter housing (5.1) is connected to a hub (4). A pump impeller (5.3) of the torque converter (5) is fixedly connected to a converter housing (5.1) of the torque converter (5). A stator (5.4) of the torque converter (5) is non-rotatably supported in one direction of rotation via a freewheel. A turbine impeller (5.5) of the torque converter (5) is connected to a turbine shaft (5.2) of the torque converter (5). The hybrid module further has an additional, optional torsional vibration damper (10), which is arranged inside and on the converter housing (5.1). The turbine shaft (5.2) is connected to an output shaft (6) of an automatic transmission (not shown in detail). A lock-up clutch (11) is also arranged inside the converter housing (5.1). By closing the lock-up clutch (11), the converter housing (5.1) can be directly connected to the turbine shaft (5.2).

[0032] The hub (4) is designed as a hollow shaft, which is arranged coaxially to the output shaft (6) and envelops it. In the example shown, the input shaft (3) is also designed as a hollow shaft and is arranged coaxially to the hub (4). Between the output shaft (6) and the hub (4), between the hub (4) and the input shaft (3), and between the input shaft (3) and the housing (1), several bearings (12) are provided, which support the components relative to one another. On its outer side, the hub (4) is connected to the converter housing (5.1) and to one side of the clutch (7).

[0033] A vibration damper (8) is provided on the input shaft (3), which is connected to a combustion engine (not shown). The vibration damper (8) reduces any torsional vibrations in order to supply the hybrid module with as uniform a torque or rotational movement as possible. At the same time, the vibration damper (8) can compensate for position and alignment tolerances between the combustion engine and the hybrid module.

[0034] The housing (1) separates a wet chamber of the hybrid module from a dry chamber. The wet chamber is sealed from the dry chamber by a seal (9), which is preferably arranged directly next to a bearing (12).

[0035] A clutch (7) is also provided within the housing (1), with which the combustion engine can be separated from the rest of the drive train. For this purpose, the clutch (7) is arranged in the power flow between the input shaft (3) and the hub (4). More precisely, the parts of the clutch (7) are connected to the input shaft (3) and to a rotor carrier. In the illustrated embodiment, the clutch (7) is designed as a multi-disk clutch.

[0036] The rotor (2.2) of the electric machine (2) is connected to a base body (13) of the rotor carrier. The base body (13) has a tubular structure, on whose outer circumferential surface the rotor (2.2) is mounted. In the illustrated embodiment, the axial end of the base body (13) facing the torque converter (5) is deformed outwards to form a collar which partially covers the rotor (2.2) in the radial direction. The collar therefore protects the rotor (2.2) and can be used as a stop for positioning the rotor (2.2). By means of corresponding recesses or balancing elements (not shown), the collar can also be used to guide oil for lubricating and cooling the electric machine (2) or for balancing the electric machine (2). The opposite axial end of the base body (13) is flat and flush with the outer circumferential surface to facilitate the assembly of the rotor (2.2).2). To secure the axial position of the rotor (2.2) on the base body (13), a locking element (15) is provided in a groove. The locking element (15) can be at least partially resilient to compensate for manufacturing tolerances and the like.

[0037] In addition to the base body (13), the rotor carrier comprises a connecting element (14). In the exemplary embodiment shown, the connecting element (14) is also largely tubular. An axial section of the connecting element (14), which runs coaxially to the base body (13), is provided with a profile in order to form elevations and depressions distributed over the circumference in the manner of a spline. These elevations and depressions serve as receptacles for parts of the clutch (7), in the example shown as receptacles for the outer plates of the clutch (7), whereby the connecting element (14) represents the outer plate carrier of the clutch (7). In order to form a connection area for connection to the base body (13), the axial end of the connecting element (14) facing the combustion engine is deformed radially outwards and forms a projection.The outer circumferential surface of the connection area is firmly connected to the inner circumferential surface of the base body (13), preferably by welding. At the opposite axial end of the connecting element (14), facing the torque converter (5), a projection is also provided, but radially inward, to form a flange area. In the illustrated embodiment, the flange area is relatively short, thereby improving the stability of the connecting element (14), and is connected directly to the converter housing (5.1). Depending on the geometry of the components, the connection to the converter housing (5.1) can be made not only in the area of ​​the edge shown but also on a circumferential surface or an end face of the torque converter (5).

[0038] Fig. 2 shows a further embodiment of a hybrid module according to the invention analogous to Fig. 1. The basic structure is the same, which is why reference is made to the description above.

[0039] Contrary to the example from Fig. 1, the connecting element (14) is not attached directly to the converter housing (5.1), but is connected to the hub (4), to which the converter housing (5.1) is also connected. For this purpose, the flange area is designed with a larger radial extension, giving the connecting element (14) a pot-like shape.

[0040] The axial section of the connecting element (14) is similar to Fig. 1 is formed on the inner circumferential surface as an outer disk carrier of the clutch (7). In this embodiment, the outer circumferential surface of the connecting element (14) almost abuts an inner circumferential surface of the base body (13).

[0041] The connection area of ​​the connecting element (14) is formed by a coaxial and radially outwardly offset area which is firmly connected to an area of ​​the base body (13) which projects axially beyond the rotor (2.2).

[0042] The base body (13) features elevations and depressions, here in the form of axially extending grooves, on the outer circumferential surface for receiving and securing the rotor (2.2). Locking elements (15) are provided for axially positioning the rotor (2.2) on the base body (13) and the coupling parts on the connecting element (14).

[0043] In Fig. 3 shows an enlarged view of the connection area between the connecting element (14) and the base body (13). In the connecting element (14), the recesses and elevations are designed to accommodate parts of the coupling (7) by appropriate profiling of the sheet-like material for the connecting element (14). As a result, the connecting element (14) has a constant wall thickness over its circumference. In the base body (13), the grooves can also be created by profiling. In the illustrated embodiment, however, the grooves are introduced into a solid base body (13), for example by machining, whereby the base body (13) has a constant inner diameter in the area of ​​the rotor (2.2) and the wall thickness changes accordingly over the circumference. For axial limitation, circumferential annular grooves for securing elements (15) are provided in both the base body (13) and the connecting element (14).

[0044] In the axial end region, which is designed as a connection region, the connecting element (14) has an enlarged diameter without any profiling. This connection region abuts a corresponding axially extending region of the base body (13) and is connected to it. The connection is preferably made by welding along the common end face. Alternatively or additionally, the connection between the base body (13) and the connecting element (14) can also be established in the adjacent connection region by riveting, clinching, spot welding, or other flat joining methods.

[0045] Fig. 4 shows a perspective view of a partial area of ​​a base body (13) and a connecting element (14). Here, the connecting element (14) is also profiled over the circumference in order to form elevations and depressions for receiving parts of the coupling (7). This profiling extends into the connection area. In order to achieve a positive connection, especially in the circumferential direction, the base body (13) has an embossing which coincides in the radial direction with a depression on the outer circumference of the connecting element (14) and engages therein. Depending on the further geometry and loads, a further fastening, in particular in the axial direction, can preferably be provided by one of the Fig. 3 listed connection types are provided.

[0046] The Fig. 5, Fig. 6 and Fig. 7 each show a part of a hybrid module in the area of ​​the clutch analogous to Fig. 1 and Fig. 2 for different examples. Fig. 5 to 7 have in common that an input shaft (3) is connected to a clutch (7), more precisely to its input side. Parts of the clutch, more precisely the output side, are connected to a connecting element (14), which also forms the outer disk carrier. The connecting element (14) is connected to the hub (4) and thus to the further drive train. Furthermore, the connecting element (14) is connected to a base body (13), and the base body (13) accommodates a rotor (2.2) on an outer circumferential surface. The connecting element (14) and the base body (13) together thus form the rotor carrier.

[0047] In the examples of the Fig. 5, Fig. 6 and Fig. In Figure 7, both the base body (13) and the connecting element (14) are provided with a profile to create a positive connection at least in the circumferential direction. Differences between the embodiments lie primarily in the further design of the connecting elements (14) and base body (13) shown.

[0048] The connection area of ​​the connecting element (14) is in Fig. 5 is deformed radially outward to form a collar. The base body (13) abuts with an axial end face against an axial end face of the collar of the connecting element (14), and these end faces are welded together, thus the weld seam runs radially.

[0049] Fig. 6 is basically identical to Fig. 5, wherein the collar of the connecting element (14) is shorter, and the outer peripheral surface of the collar of the connecting element (14) abuts an inner peripheral surface of the base body (13), wherein these peripheral surfaces are welded together. The weld seam thus runs axially. In principle, other contact surface pairings are also possible instead of end faces or peripheral surfaces, where, for example, the weld seam runs obliquely or contact surfaces arranged at an angle to each other are welded with a fillet weld.

[0050] In addition to a connection in the connection area of ​​the connecting element (14), additional connections (not shown) can be made along the axial section when it contacts the base body. The additional connections can be made, in particular, by spot welding, riveting, or clinching.

[0051] In the example in Fig. 7, the base body has an inwardly directed collar at its axial end facing away from the converter housing (5.1). Adjacent to this collar is a locking element (15), which serves as an axial stop for the connecting element (14). The base body (13) also has locking elements (15) on the outside to axially position the rotor (2.2).

[0052] The invention is not limited to the described embodiments. As explained above, only individual advantageous features may be provided, or various features from different examples may be combined. Reference symbol 1 housing 2 electric machine 2.1 Stator 2.2 Rotor 3 Input shaft 4 Hub 5 torque converters 5.1 Converter housing 5.2 Turbine shaft 5.3 Pump wheel 5.4 Idler 5.5 Turbine wheel 6 Output shaft 7 Clutch 8 vibration dampers 9 Seal 10 torsional vibration dampers 11 Lock-up clutch 12 camps 13 basic bodies 14 Connecting element 15 Securing element

Claims

[1] Rotor carrier for a rotor (2.2) of an electrical machine (2), wherein the rotor carrier comprises a tubular base body (13), wherein the base body (13) has means on an outer circumferential surface facing the rotor (2.2) which enable a positive and / or non-positive connection between the base body (13) and the rotor (2.2), and wherein a connecting element (14) has an axial section which runs coaxially to the base body (13), and wherein receptacles for parts of a coupling (7) are provided on an inner circumferential surface of the axial section facing away from the base body (13), characterized by that the connecting element (14) connects the base body (13) to a hub (4), that the axial section of the connecting element (14) extends over part of the axial length of the base body (13), and that the connecting element (14) has a flange region adjoining the axial section. [2] Rotor carrier according to claim 1, characterized by that the axial section of the connecting element (14) has an axial length in the range of 25% to 75% of the axial length of the base body (13). [3] Rotor carrier according to claim 1 or 2, characterized by that the connecting element (14) has a connection area at the axial end opposite the flange area, and that the connection area is connected to the base body (13). [4] Rotor carrier according to claim 3, characterized by that the connection region is connected to an axial end of the base body (13), and that the axial section runs coaxially within the base body (13). [5] Rotor carrier according to one of the preceding claims, characterized by that the axial section rests against the base body (13). [6] Rotor carrier according to one of the preceding claims, characterized bythat the base body (13) and / or the connecting element (14) has a cross-section which is changed in the radial direction at at least one point along the axial extent in order to form a stop for positioning the base body (13) and the connecting element (14) relative to one another. [7] Rotor carrier according to one of the preceding claims, characterized by that the connection between the base body (13) and the connecting element (14) is positively connected at least in one direction. [8] Rotor carrier according to one of the preceding claims, characterized by that the connection between the base body (13) and the connecting element (14) is materially bonded at least in one direction. [9] Rotor carrier according to claim 8, characterized by that a weld seam between the base body (13) and the connecting element (14) runs coaxially between two circumferential surfaces or between two end surfaces. [10] Rotor carrier according to one of the preceding claims, characterized by that the flange area is directly connected to a converter housing (5.1), or that the flange area extends in the radial direction and is connected to a hub (4). [11] Rotor carrier according to one of the preceding claims, characterized by that the base body (13) and / or the connecting element (14) is longer than the rotor (2.2) at least at one axial end. [12] Rotor carrier according to one of the preceding claims, characterized by that the base body (13) and / or the connecting element (14) has at least one recess which is continuous in the radial direction for the passage of oil. [13] Rotor carrier according to claim 12, characterized by that several recesses are arranged around the circumference. [14] Rotor carrier according to one of the preceding claims, characterized bythat the base body (13) is made from a formed pipe section. [15] Rotor carrier according to one of the preceding claims, characterized by that the connecting element (14) is made of a formed sheet metal. [16] Hybrid module comprising an input shaft (3), a clutch (7), an electric machine (2), a torque converter (5) and an output shaft (6), characterized by that a rotor carrier according to one of claims 1 to 15 is provided.

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