Assembly for grounding shaft, transmission mechanism, electric axle drive unit for motor vehicle, and electric machine

Abstract

The utility model relates to an assembly for grounding a shaft (7), which comprises a grounding hub (13) which is at least partially tubular, and the grounding hub is conductively connected with an electric grounding part. The grounding hub is also electrically conductively connected to the shaft to be grounded by means of a sliding contact (15) formed on a contact element (16) which is guided in a holder (17) which is fixed to the grounding hub on the end face of the grounding hub. The inner volume of the grounding hub also forms a feed line (27) for feeding a lubricating medium and / or a cooling medium to the shaft to be grounded. The delivery line opens into a collection space (32) which is defined between the grounding hub and the holder. At least one hole (33) is formed in the holder, via which the collecting space is connected to at least one supply line (35) of the shaft to be grounded. The utility model further relates to a transmission mechanism, an electric axle driving unit for a motor vehicle and a motor, wherein the transmission mechanism, the electric axle driving unit and the motor are correspondingly provided with the components.

Description

Technical Field

[0001] The utility model relates to a component for grounding a shaft, especially a rotor shaft of an electric motor, the component comprising a grounding hub which is at least partially tubular, the grounding hub being conductively connected to an electrical grounding portion, preferably to a housing, the grounding hub being conductively connected to a shaft to be grounded through a sliding contact constructed on a contact element, the contact element being guided in a retaining member, the retaining member being fixed to the grounding hub at the end side of the grounding hub, and the inner volume of the grounding hub constituting a delivery pipeline for delivering a lubricating medium and / or a cooling medium to the shaft to be grounded. In addition, the utility model relates to a transmission mechanism, an electric axle drive unit for a motor vehicle, and an electric motor, wherein the aforementioned components are respectively implemented in the transmission mechanism, the electric axle drive unit, and the electric motor. Background Art

[0002] In the field of motor vehicles, electric motors are used to design the corresponding motor vehicles as hybrid vehicles or electric vehicles. Therefore, in some cases, electric motors are also provided in the motor vehicle transmission mechanism so that the corresponding motor vehicle transmission mechanism is suitable for use in hybrid vehicles or electric vehicles. However, while the remaining components of the corresponding transmission mechanism are encapsulated and shielded by the corresponding surrounding transmission mechanism housing, the shafts led out of the transmission mechanism housing can cause electromagnetic interference, which can cause failures of other electronic components in the area of ​​the motor vehicle. In addition, a potential difference can be generated between the corresponding shaft and the transmission mechanism housing, which may cause breakdown at the bearing of the corresponding shaft and thus reduce the service life of the bearing. For the reasons mentioned, the shaft, especially the rotor shaft of the motor vehicle, should be grounded as much as possible. In the motor originally arranged in the motor vehicle, for example, in the electric axle drive unit, the corresponding shaft should also be grounded. Here, the corresponding grounding is achieved by the conductive connection of the shaft to be grounded with the electrical grounding part, and the electrical grounding part is, for example, the housing.

[0003] DE102019133677A1 discloses a component for grounding the rotor shaft of an electric motor, wherein the rotor shaft is electrically conductively connected to the housing via a tubular grounding hub. Here, the grounding hub is supported on the rotor shaft via a support bearing at one axial end and is floatingly supported in the housing cover of the housing at the opposite axial end. For the floating support, a conductive, radially elastic intermediate element is radially arranged between the grounding hub and the housing cover. On one side of the rotor shaft, an electrically conductive connection is established between the grounding hub and the rotor shaft as a sliding contact by a contact element implemented as a carbon pin. Here, the carbon pin is arranged on the rotor shaft and guided in a carbon brush holder arranged on the grounding hub. The electrically conductive connection between the grounding hub and the rotor shaft is formed by sliding contact between the carbon pin and the carbon brush holder. In addition to the electrically conductive connection between the rotor shaft and the housing, the grounding hub is also used to transport oil from the housing to the rotor shaft, for which the oil is introduced into the inner volume of the tubular grounding hub. Utility Model Content

[0004] Starting from the above-mentioned prior art, the object of the present invention is now to provide an arrangement by means of which a shaft can be reliably grounded, wherein at the same time a supply of lubricating and / or cooling medium to the shaft to be grounded should be ensured.

[0005] To this end, the utility model proposes a component for grounding a shaft, the component comprising an at least partially tubular grounding hub, the grounding hub being electrically conductively connected to an electrical grounding portion, the grounding hub also being electrically conductively connected to a shaft to be grounded via a sliding contact constructed on a contact element, the contact element being guided in a retaining member, the retaining member being fixed to the grounding hub at the end side of the grounding hub, and the inner volume of the grounding hub constituting a delivery line for delivering a lubricating medium and / or a cooling medium to the shaft to be grounded, wherein the delivery line leads into a collecting space, the collecting space being defined between the grounding hub and the retaining member, at least one hole being constructed in the retaining member, the collecting space being connected to at least one supply line for a lubricating medium and / or a cooling medium of the shaft to be grounded via the hole. A transmission mechanism in which at least one shaft is arranged in a manner according to the utility model is also the subject of the utility model. In addition, the utility model relates to an electric axle drive unit, in which at least one shaft is arranged according to the component according to the utility model, and the utility model also relates to an electric motor having a rotor shaft arranged in a manner according to the utility model.

[0006] According to the utility model, a component for grounding a shaft comprises a grounding hub which is at least partially tubular, and the grounding hub is electrically conductively connected to an electrical grounding portion, and the electrical grounding portion is preferably a housing. The grounding hub is also electrically conductively connected to the shaft to be grounded through a sliding contact constructed on a contact element, and the contact element is guided in a retaining member, and the retaining member is fixed to the grounding hub at the end side of the grounding hub. The inner volume of the tubular grounding hub also constitutes a delivery pipeline for delivering a lubricating medium and / or a cooling medium to the shaft to be grounded.

[0007] In the sense of the present invention, a "shaft" is to be understood in principle as a rotatable component, which is usually provided for transmitting a rotational movement between the components to be coupled. Here, the shaft can also be constructed as a single piece with one or both of the components to be coupled. Particularly preferably, the shaft to be grounded is the rotor shaft of an electric motor, which can be part of a motor vehicle transmission, but in principle, the shaft can also be another shaft, for example, in particular a transmission shaft. Furthermore, within the scope of the present invention, the shaft to be grounded can be one-piece or multi-piece.

[0008] In the assembly according to the invention, the grounding hub is provided for connecting the shaft to be grounded to the grounding part in an electrically conductive manner by connecting the grounding hub to the shaft to be grounded on the one hand and also to the grounding part on the other hand. At least on the side of the shaft to be grounded, an electrically conductive connection is established at the end side of the grounding hub by making contact on a contact element, which is guided in a holder fixed to the end side of the grounding hub. Here, an electrically conductive connection must also exist between the contact element and the holder and between the holder and the grounding hub, respectively.

[0009] At least in the contact area with the grounding part and in the contact area with the shaft to be grounded via the intermediate retaining part and the contact element and in the intermediate area connecting these contact areas, the grounding hub is made of an electrically conductive material. However, preferably, the grounding hub is composed completely of an electrically conductive material, in particular a metallic material such as steel or aluminum.

[0010] In addition to achieving an electrically conductive connection between the shaft to be grounded and the grounding part, the grounding hub also has the function of enabling the supply of lubricating and / or cooling media to the shaft to be grounded, for which purpose the grounding hub is designed at least partially tubular. Here, the lubricating and / or cooling media can be conducted to the shaft to be grounded via the inner volume of the tube, which is at least partially defined, and the supply line formed thereby, wherein the medium is preferably oil, which is provided for cooling the shaft, which is in particular designed as a rotor shaft, or a rotor attached thereto.

[0011] In the sense of the present invention, the grounding hub has a rod-like shape, that is, the grounding hub is implemented as an elongated component similar to a shaft, so as to establish an electrically conductive connection between the shaft to be grounded and the grounding part, preferably axially, in the assembly according to the present invention. Here, the grounding hub is configured to be tubular at least over a portion of its extension, in such a way that the internal volume is bounded by the surrounding material of the grounding hub in at least an existing subsection of the grounding hub and the conveying line is thus defined in said area. However, it is particularly preferred that the grounding hub is completely configured as a tube, so that the conveying of the lubricating medium and / or the cooling medium can thus be achieved over the entire axial extension of the grounding hub, and thus also the medium can be guided from one axial end of the grounding hub to the other axial end. It is more preferred here that the grounding part-side connector for the lubricating medium and / or the cooling medium is connected to the shaft to be grounded via the grounding hub. It is also preferred that the grounding hub is configured to be rotationally symmetrical.

[0012] The grounding part, which is electrically connected to the shaft to be grounded via the centrally located grounding hub, is an electrical conductor in the sense of the present invention, which is provided with a zero potential as a reference potential in particular. Preferably, the grounding part is in the form of a housing, wherein the electrically conductive connection of the grounding hub can be established specifically on the housing, on a housing part or on a component which is permanently electrically conductively connected thereto.

[0013] Within the scope of the present invention, “axial” refers to the orientation in the direction of the rotation axis of the shaft or the center axis of the grounding hub, while radial refers to the orientation in the diameter direction starting from the rotation axis of the shaft to be grounded or from the center axis of the grounding hub.

[0014] In the sense of the present invention, an "electrically conductive" connection is understood to be a connection that enables a current flow between the connected components. In the assembly according to the present invention, such an electrically conductive connection is formed on the one hand between the grounding part and the grounding hub and on the other hand between the grounding hub and the shaft to be grounded, wherein the latter is realized indirectly via the contact element and the holder.

[0015] The present invention now includes the following technical teaching, namely, that the conveying line opens into a collecting space, which is defined between the grounding hub and the retaining element. Here, at least one hole is constructed in the retaining element, via which the collecting space is connected to at least one supply line for a lubricating medium and / or a cooling medium of the shaft to be grounded. In other words, the conveying line defined by the internal volume of the grounding hub ends on one side of the shaft to be grounded in the collecting space, which is delimited by the grounding hub together with the retaining element fixed to the end side of the grounding hub. Here, in addition to the conveying line, the collecting space is also connected to at least one supply line of the shaft to be grounded, in that at least one hole connecting the collecting space and the supply line is constructed in the retaining element.

[0016] Such a component for grounding a shaft has the advantage that, on the one hand, an electrically conductive connection is established between the shaft to be grounded and the grounding hub by means of a sliding contact on the contact element between the shaft to be grounded and the grounding hub, which also enables reliable grounding of the shaft due to the electrically conductive connection of the grounding hub to the grounding portion. However, at the same time, the grounding hub can also be used to guide the lubricating medium and / or the cooling medium to the shaft to be grounded, so as to ensure corresponding lubrication or cooling by the medium there. Although the holder is arranged on the end side and is therefore also contacted and conducted on the end side via the contact element guided in the holder, the lubricating medium and / or the cooling medium can still be guided to the shaft to be grounded without any problems, in that the medium guided to the grounding hub via the internal volume and thus via the conveying line can be collected in the collecting space between the grounding hub and the holder, and in addition, it can then reach the shaft to be grounded from the collecting space via the at least one hole in the direction of the at least one supply line. Therefore, overall, reliable grounding of the shaft can be achieved while supplying the lubricating medium and / or the cooling medium to the shaft.

[0017] Although in the assembly according to DE 10 2019 133 677 A1, contact is also made between the shaft to be grounded and the grounding hub by sliding contact, in that a contact element fixed to the shaft to be grounded is guided in a holder, which is fixed to the grounding hub at the end side of the grounding hub. However, DE 10 2019 133 677 A1 does not take measures to guide the lubricating medium and / or cooling medium conveyed via the grounding hub to the shaft to be grounded through the holder.

[0018] In the context of the invention, the at least one hole in the holder is preferably designed as a radially extending hole so that the lubricating medium and / or cooling medium that has entered the collecting space can flow radially outward from the collecting space. In principle, however, the at least one hole can also be designed to extend axially and radially and also to extend purely axially, provided that the guidance of the contact element and thus the electrical contacting is not impaired thereby.

[0019] According to one embodiment of the utility model, the contact element is guided in a movable manner in the holder and is pre-tensioned in the holder against a thrust surface, which is constructed on the side of the shaft to be grounded. Therefore, the contact element on which the sliding contact between the contact counterpart in the form of the shaft to be grounded and the grounding hub is established is accommodated in the holder in a movable manner. The sliding contact on the contact element is constructed so that the contact element in the holder contacts the thrust surface constructed on the side of the shaft to be grounded due to the pre-tensioning. This has the following advantages, namely, the electrical contact conduction can be constructed in a reliable manner by the movable guidance of the contact element in the holder and the pre-tensioning of the contact element against the thrust surface. This is because the pre-tensioning of the contact element against the thrust surface always ensures that the contact element is in contact with the thrust surface during operation and thus produces a conductive sliding contact.

[0020] On the grounding hub side, an electrically conductive connection to the contact element is established via a retaining element, which is fixed to the end face of the grounding hub, wherein the fixing must be designed to be electrically conductive. The prestressing of the contact element against the stop face is achieved in particular via a spring element, which is placed between the retaining element and the contact element and prestresses the contact element in the direction of the stop face. The electrically conductive connection of the retaining element to the contact element is achieved here on the basis of the guidance of the contact element in the retaining element and / or via the spring element. The spring element is particularly preferably a helical spring, but compact embodiments of the spring element are also conceivable, such as a disc spring or a wave spring.

[0021] The contact element is guided in the holder in particular in an axially movable manner and is then also axially preloaded against the thrust surface. In principle, however, within the scope of the invention, radial contacting can also be achieved via the contact element by guiding the contact element radially in the holder and preloaded against the thrust surface.

[0022] According to a feasible design scheme in the above-mentioned embodiment, the thrust surface is constructed on the first sleeve, and the first sleeve is fixed on the shaft to be grounded. Therefore, in this case, the conductive connection between the contact element and the shaft to be grounded is constructed on the first sleeve, the first sleeve constitutes the thrust surface for the contact element and the first sleeve is fixed on the shaft to be grounded. As a result, the following feasibility exists: in order to construct the sliding contact with the contact element, the following material is used, which has a high electrical conductivity and further realizes a low-wear contact partner for sliding contact with the contact element, while the shaft to be grounded does not have to be completely or at least mostly composed of this material. This is because the first sleeve can be fixed on the shaft to be grounded in a targeted manner in the area where the sliding contact occurs. Particularly preferably, the first sleeve is fixed to the shaft to be grounded by a crimping connection.

[0023] In a refinement of the above-mentioned possible design, the first sleeve is fixed to the inner diameter of the shaft, which is configured as a hollow shaft at least in the region, and separates the at least one supply line from the inner space, which is connected to the collecting space via the at least one hole of the holder. In addition, the first sleeve is penetrated by at least one recess, through which a connection between the inner space and the at least one supply line of the shaft to be grounded is established. Advantageously, the first sleeve can be arranged particularly compactly in that the first sleeve is fixed to the inner diameter of the shaft to be grounded. At the same time, however, the lubricating medium and / or the cooling medium can be delivered to the shaft to be grounded via the at least one recess almost unhindered. Preferably, the first sleeve is pressed into the inner diameter of the shaft to be grounded. More preferably, the inner space separated from the at least one supply line by the first sleeve is defined between the holder, the shaft to be grounded and the first sleeve.

[0024] According to one embodiment of the invention, the at least one supply line of the shaft to be grounded is formed by the inner volume of the shaft which is designed as a hollow shaft at least in the region. As a result, the conveyed lubricating medium and / or cooling medium can also be easily guided in the region of the shaft to be grounded by configuring the shaft to be grounded as a hollow shaft at least in the region relevant for the guidance.

[0025] In a further development of the invention, the grounding hub is inserted axially into the shaft to be grounded, wherein the sliding contact on the contact element takes place in the inner space bounded between the grounding hub and the shaft to be grounded. This has the advantage that the sliding contact between the grounding hub and the shaft to be grounded can thus take place in the shielded area.

[0026] Another embodiment of the invention is that the contact element is made of an electrically conductive material, for example graphite. The contact element being a graphite element enables high electrical conductivity while providing a problem-free construction of the sliding contact.

[0027] According to a possible design of the utility model, a bearing, preferably a rolling bearing, is arranged between the grounding hub and the shaft to be grounded. Advantageously, the grounding hub can also be supported in the region of the shaft to be grounded and at the same time a relative rotation speed between the grounding hub and the shaft to be grounded can be achieved. Particularly preferably, the bearing implemented as a rolling bearing is configured as a deep groove ball bearing. In a refinement of the possible design, the bearing can be radially accommodated between the retaining element and the shaft to be grounded, but the bearing is preferably arranged on the grounding hub with an inner ring.

[0028] In an improved solution of the utility model, the delivery pipeline of the grounding hub is connected to the radial outer area of ​​the grounding hub via at least one hole. As a result, a part of the lubricating medium and / or cooling medium guided via the delivery pipeline can also be guided to the radial outer area of ​​the grounding hub, so as to supply other components in addition to the shaft to be grounded, such as a bearing part and / or a meshing part, etc. Particularly preferably, when the improved solution is combined with the aforementioned feasible design solution, the at least one hole is arranged to be axially adjacent to the inner ring of the bearing, and the inner ring is arranged between the grounding hub and the shaft to be grounded. In particular, the at least one hole is also configured to be located vertically below in the installation position of the grounding hub, so as to enable a part of the lubricating medium and / or cooling medium to flow out through the at least one hole without problems.

[0029] According to one embodiment of the utility model, the grounding hub is implemented with a reduced diameter at the mouth leading to the collecting space. As a result, the amount of lubricating medium and / or cooling medium can be adjusted by correspondingly configuring the flow cross section. Alternatively or in addition to this, a second sleeve is inserted into the grounding hub in the area of ​​the mouth leading to the collecting space. As a result, the flow cross section of the grounding hub can also be adjusted accordingly.

[0030] Particularly preferably, the grounding hub is fixed, so that the lubricating medium and / or the cooling medium can flow in the grounding hub via the conveying line more easily due to the non-rotation of the grounding hub. For this purpose, the grounding hub can be fixed on one side of the grounding part to prevent rotation.

[0031] The subject of the invention is also a transmission, in particular a motor vehicle transmission, in which at least one shaft is grounded in a component according to one or more of the above-described variants. The component can be implemented in particular in a rotor shaft of an electric machine integrated into the transmission, but the component according to the invention for grounding a shaft can also be a component of an electric machine or an electric axle drive unit for a motor vehicle.

[0032] The invention is not limited to the given combination of features of the independent claims or their dependent claims. In addition, individual features can be combined with one another as long as they are derived from the claims, the following description of preferred embodiments of the invention or directly from the drawings. The reference of the claims to the drawings by using reference numerals shall not limit the scope of protection of the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The advantageous embodiments of the present invention explained below are shown in the accompanying drawings. In the accompanying drawings:

[0034] Figure 1 A schematic diagram showing a powertrain of a motor vehicle;

[0035] Figure 2 Show Figure 1 A cross-sectional view of a region of a power train in the region of an assembly for grounding a shaft according to the present invention;

[0036] Figure 3 a schematic diagram showing a powertrain of a motor vehicle; and

[0037] Figure 4 A schematic diagram of the motor is shown. DETAILED DESCRIPTION

[0038] Figure 1 A drive train for a motor vehicle is schematically shown, which is a purely electric drive train in this case. The drive train has an electric axle drive unit 1. The electric axle drive unit 1 comprises an electric motor 2, the power of which is transmitted to drive wheels 5 and 6 of the motor vehicle via a reduction gear set 3 and a differential 4. For this purpose, the electric motor is connected to the reduction gear set 3 on the output side of a shaft 7. The output shafts 8, 9 of the differential 4 are connected to the drive wheels 5, 6. The electric motor 2, the reduction gear set 3 and the differential 4 are surrounded by a housing 10.

[0039] A converter 11 is fixed to the housing 10. The converter 11 is connected to the motor 2 on one hand and to the battery 12 on the other hand. The converter 11 is used to convert the direct current of the battery 12 into alternating current suitable for operating the motor 2, and has a plurality of power semiconductors for this purpose. The conversion between direct current and alternating current is performed by controlled pulse operation of the power semiconductors.

[0040] In order to prevent electromagnetic interference and the generation of potential differences during operation (which could otherwise lead to breakdown at the bearings of the shaft 7), the shaft 7 is grounded. This is achieved in a preferred embodiment of the present invention and in Figure 2 The components shown in more detail are implemented within the context of FIG.

[0041] Therefore, the shaft 7 is connected to the ground via the ground hub 13. Figure 2 The housing 10 as a grounding part, which is not visible in the figure, is electrically connected. Here, the grounding hub 13 is designed to be tubular and is made completely of an electrically conductive material, in particular a metal. Figure 2 At the axial end not visible in the figure, the grounding hub 13 is electrically conductively connected to the housing 10 forming the grounding part, and the electrically conductive connection between the grounding hub 13 and the housing 10 can be realized here, in particular, in the housing cover of the housing, either by direct contact between the cover and the grounding hub 13 or indirectly via contact-conducting elements located in between. The grounding hub 13 is fixed here and thus prevented from rotating movement, which is preferably realized by a rotation prevention device between the grounding hub 13 and the housing 10 or the housing cover.

[0042] At the axial end 14 opposite the electrical contact-through of the housing 10, the grounding hub 13 is electrically conductively connected to the shaft 7 to be grounded, which is achieved here by means of a sliding contact 15 on a contact element 16. The contact element 16 is made of an electrically conductive material, for example graphite, and is guided in an axially displaceable manner in a holder 17, which is fixed to the grounding hub 13 at the axial end 14. Here, the contact element 16 is guided in an axially displaceable manner in a guide bore 18 of the holder 17 and is prestressed against a stop surface 20 formed on a first sleeve 21 by means of a spring element 19 in the form of a helical spring.

[0043] The first sleeve 21 is pressed into the stepped bore 22 of the shaft 7, which is designed as a hollow shaft at least in this region, and is fixed there at the inner diameter 23, the axial position of the first sleeve 21 relative to the shoulder 24 of the stepped bore 22 being adjusted by a hollow cylindrical spacing element 25. At the shoulder 24 of the stepped bore 22, the inner diameter of the stepped bore 22 is radially close to the outer diameter of the retaining element 17, which is pressed onto the end 14 of the grounding hub 13 in this region. The electrically conductive connection between the grounding hub 13 and the shaft 7 is thus established via the retaining element 17 on the contact element 16 guided therein by means of a sliding contact with the thrust surface 20 of the first sleeve 21, in that the retaining element 17 is electrically conductively connected both to the grounding hub 13 and to the contact element 16, while the first sleeve 21, in addition to the sliding contact 15 with the contact element 16, also establishes a contact connection with the shaft 7 to be grounded. Similar to the holding element 17 , the first sleeve 21 must also be produced for this purpose from an electrically conductive material, which is preferably metal in this case.

[0044] In addition to establishing an electrically conductive connection between the shaft 7 and the housing 10, the grounding hub 13 also has the additional task of guiding a lubricant and / or a cooling medium to the shaft 7 in order to cool the rotor of the electric machine. Here, the lubricant and / or the cooling medium is in particular the oil of the gear mechanism. The interior space 26 of the tubular grounding hub 13 is connected to a supply connection of the housing 10 (not shown further at this moment) in order to introduce the lubricant and / or the cooling medium into the interior space 26 of the grounding hub 13. Particularly preferably, the lubricant and / or the cooling medium is introduced here from the axial end of the grounding hub 13 at which an electrically conductive contact between the grounding hub 13 and the housing 10 is constructed.

[0045] The interior space 26 of the grounding hub 13 thus forms a delivery line 27 for conveying the introduced lubricating and / or cooling medium to the axial end 14 of the grounding hub 13. Here, the grounding hub 13 is provided with a diameter reduction 28 in the region of the axial end 14, which also leads to a reduction in the flow cross section of the delivery line 27 toward the axial end 14. In the present case, the flow cross section is additionally reduced here by a second sleeve 29, which is pressed into the grounding hub 13 at the axial end 14 in the region of the mouth of the delivery line 27. The amount of lubricating and / or cooling medium directed to the axial end 14 of the grounding hub 13 is adjusted here by the diameter reduction 28 and the second sleeve 29.

[0046] At the reduced diameter portion 28, on the one hand, the retaining element 17 is fixed on the outer diameter of the grounding hub 13 defined thereby by pressing the retaining element 17, whereby the retaining element 17 is placed on the end side of the grounding hub 13 and thus also realizes an electrically conductive connection with the shaft 7 on the end side of the grounding hub 13. On the other hand, an inner ring 30 of a bearing 31 is also placed on the outer diameter of the reduced diameter portion 28, the bearing being arranged radially between the grounding hub 13 and the shaft 7 and serving to support the shaft 7 relative to the grounding hub 13. The bearing 31 is implemented here as a rolling bearing, which is specifically configured as a deep groove ball bearing.

[0047] In order to ensure that the lubricating and / or cooling medium is supplied to the shaft 7 despite the end-side placement of the holder 17, a collecting space 32 is defined in the mouth region of the supply line 27 and therefore on the end side of the grounding hub 13. The collecting space 32 is enclosed here between the holder 17 and the grounding hub 13 in that the holder 17 is provided with a stepped bore, with which the holder 17 is pressed onto the axial end 14 of the grounding hub 13 in a first diameter region and delimits the collecting space 32 in a second diameter region axially adjacent thereto.

[0048] The collecting space 32 is supplied with lubricating medium and / or cooling medium from the delivery line 27, wherein the medium can flow out from the collecting space 32 via radially extending holes 33 into an inner space 34, which is defined between the retaining element 17, the spacing element 25 and the first sleeve 21 in a manner that radially surrounds the retaining element 17. The lubricating medium and / or cooling medium can then pass from the inner space 34 through the first sleeve 21 to the supply line 35 formed by the stepped hole 22 of the shaft 7. In this case, the outflow from the inner space 34 to the supply line 35 can be achieved by an axial recess 36 in the first sleeve 21. In this regard, the lubricating medium and / or cooling medium can generally be provided as follows Figure 2 The flow path is shown by arrows.

[0049] The grounding hub 13 is further provided with radial holes 37, which are located vertically below and axially between an area on which the inner ring 30 of the bearing 31 is placed and another area on which the retaining element 17 is pressed onto the axial end 14 of the grounding hub 13, through which a portion of the lubricating medium and / or cooling medium guided via the supply line 27 can reach the radial outer area of ​​the grounding hub 13 before being conveyed into the collecting space 32. Due to the funnel-like configuration of the shaft 7 axially between the placement of the bearing 31 and the formation of the shoulder 24, the lubricating medium and / or cooling medium flowing out via the holes 37 is guided in the direction of the bearing 31 and then also guided to the area following it in the axial direction in order to supply further bearing locations and / or toothings.

[0050] In addition, from Figure 3 A schematic diagram of a powertrain for a motor vehicle is obtained. Figure 1 In a variant of the invention, the drive train has an internal combustion engine 38, the output of which is connected to an input shaft 39 of a transmission 40. An output shaft 41 of the transmission 40 is connected to a differential 42. The differential 42 is designed to distribute the power present at the output shaft 41 to drive wheels 43 and 44 of the motor vehicle. The transmission 40 has a gear set 45, which is connected to the input shaft 39 of the transmission 40. The output shaft 41 of the transmission 40 is connected to a differential 42. The differential 42 is designed to distribute the power present at the output shaft 41 to drive wheels 43 and 44 of the motor vehicle. Figure 3 The gear set 45 is designed together with the shifting elements (not shown) to provide different transmission ratios between the input shaft 39 and the output shaft 41. The gear set 45 is surrounded by a housing 46, which also accommodates an electric motor 47 connected to the input shaft 39. The electric motor 47 is designed to drive the input shaft 39. A converter 48 is fixed to the housing 46. The converter 48 is connected to the electric motor 47 on the one hand and to the battery 49 on the other hand. The converter 48 is used to convert the direct current of the battery 49 into an alternating current suitable for operating the electric motor 47, and has a plurality of power semiconductors for this purpose. The conversion between direct current and alternating current is performed by controlled pulse operation of the power semiconductor.

[0051] In the present case, the grounding of the input shaft 39 is achieved within the scope of the assembly according to the invention, which is similar to the one according to Figure 2 Thus, the input shaft 39 is also electrically conductively connected to a grounding hub (not shown further here) in the transmission 40 via sliding contact. In addition, the grounding hub is also used here to supply lubricating and / or cooling media to the input shaft 39 and also to the electric machine 47. For a more precise design of the components for grounding the input shaft 39, reference is made to Figure 2 .

[0052] at last, Figure 4The schematic diagram of the motor 50 is also shown. The motor 50 has a housing 51 that accommodates a stator 52 and a rotor 53. The stator 52 is fixed in the housing 51 in a rotationally fixed manner. The rotor 53 is coupled to a rotor shaft 54, which is rotatably supported via two rolling bearings 55 and 56 supported on the housing 51. One end of the rotor shaft 54 ​​protrudes from the housing 51.

[0053] In the present case, the rotor shaft 54 ​​is grounded within the scope of the assembly according to the invention, wherein the assembly is basically grounded in a manner similar to that according to Figure 2 Therefore, the rotor shaft 54 ​​is also electrically conductively connected to the grounding hub 13 in the transmission 51 by means of sliding contact. In addition, the grounding hub 13 is also used here to convey the lubricating medium and / or the cooling medium to the rotor shaft 54. For a more precise design of the components for grounding the rotor shaft 54, reference is made to Figure 2 .

[0054] By means of the arrangement according to the invention, on the one hand, grounding of the shaft can be achieved in a reliable manner and on the other hand, the supply of lubricating and / or cooling medium to the shaft to be grounded can be ensured.

[0055] Reference numerals list

[0056] 1Axle drive unit

[0057] 2 Motor

[0058] 3 reduction gear set

[0059] 4 Differential

[0060] 5 driving wheels

[0061] 6 driving wheels

[0062] 7-axis

[0063] 8 Output shaft

[0064] 9 Output shaft

[0065] 10 Shell

[0066] 11 Inverter

[0067] 12 batteries

[0068] 13 ground hub

[0069] 14 end

[0070] 15 Sliding contact

[0071] 16 contact elements

[0072] 17. Retaining Parts

[0073] 18 guide holes

[0074] 19 Spring element

[0075] 20Thrust surface

[0076] 21 First Sleeve

[0077] 22 Step Hole

[0078] 23 inner diameter

[0079] 24 Shoulders

[0080] 25 Spacer elements

[0081] 26Interior Space

[0082] 27Transmission pipeline

[0083] 28 Diameter reduction section

[0084] 29 Second sleeve

[0085] 30 Inner Ring

[0086] 31 bearings

[0087] 32 Collection Space

[0088] 33 holes

[0089] 34Interior Space

[0090] 35 Supply pipeline

[0091] 36 blank space

[0092] 37 holes

[0093] 38 Internal combustion engine

[0094] 39 Input shaft

[0095] 40 Transmission mechanism

[0096] 41 Output shaft

[0097] 42 Differential

[0098] 43 driving wheel

[0099] 44 driving wheels

[0100] 45 gear set

[0101] 46 Shell

[0102] 47 Motor

[0103] 48 Inverter

[0104] 49 Battery

[0105] 50 motor

[0106] 51 Shell

[0107] 52 stator

[0108] 53 rotor

[0109] 54 rotor shaft

[0110] 55 Rolling bearing

[0111] 56 Rolling bearings

Claims

1. A component for grounding a shaft (7), comprising an at least partially tubular grounding hub (13), which is electrically conductively connected to an electrical grounding portion, the grounding hub (13) also being electrically conductively connected to the shaft (7) to be grounded via a sliding contact (15) formed on a contact element (16), the contact element (16) being guided in a retaining element (17), which is fixed to the grounding hub (13) at its end side, and the inner volume of the grounding hub (13) forming a delivery line (27) for delivering a lubricating medium and / or a cooling medium to the shaft (7) to be grounded, characterized in that The delivery line (27) opens into a collecting space (32), which is defined between a grounding hub (13) and a retaining element (17), wherein at least one hole (33) is formed in the retaining element (17), and the collecting space (32) is connected to at least one supply line (35) for a lubricating medium and / or a cooling medium of the shaft (7) to be grounded via the hole.

2. The assembly according to claim 1, characterized in that The contact element (16) is guided displaceably in the holder (17) and is prestressed in the holder (17) against a stop surface (20) which is formed on the side of the shaft (7) to be grounded.

3. The assembly according to claim 2, characterized in that The thrust surface (20) is formed on a first sleeve (21) which is fixed to the shaft (7) to be grounded.

4. The assembly according to claim 3, characterized in that The first sleeve (21) is fixed to the inner diameter (23) of the shaft (7) which is implemented as a hollow shaft at least in the region and thereby separates the at least one supply line (35) from an inner space (34), the inner space being connected to the collecting space (32) via the at least one hole (33) of the retaining element (17), the first sleeve (21) being penetrated by at least one recess (36), through which a connection is respectively established between the inner space (34) and the at least one supply line (35) of the shaft (7) to be grounded.

5. The assembly according to claim 4, characterized in that The inner space (34) is defined between the retainer (17), the shaft to be grounded (7), and the first sleeve (21).

6. Assembly according to any one of claims 1 to 5, characterized in that The at least one supply line (35) of the shaft (7) to be grounded is formed by the inner volume of the shaft (7) which is designed as a hollow shaft at least in the region.

7. Assembly according to any one of claims 1 to 5, characterized in that The grounding hub (13) is guided axially into the shaft (7) to be grounded, wherein the sliding contact (15) on the contact element (16) takes place in an inner space defined between the grounding hub (13) and the shaft (7) to be grounded.

8. Assembly according to any one of claims 1 to 5, characterized in that The contact element (16) is made of an electrically conductive material.

9. Assembly according to any one of claims 1 to 5, characterized in that A bearing (31) is arranged between the grounding hub (13) and the shaft (7) to be grounded.

10. The assembly according to claim 9, characterized in that The bearing (31) is placed with an inner ring (30) on the grounding hub (13).

11. Assembly according to any one of claims 1 to 5, characterized in that The delivery line (27) of the grounding hub (13) is connected to a radially outer region of the grounding hub (13) via at least one hole (37).

12. Assembly according to any one of claims 1 to 5, characterized in that The grounding hub (13) is provided with a reduced diameter portion (28) at the opening leading into the collecting space (32).

13. Assembly according to any one of claims 1 to 5, characterized in that A second sleeve (29) is inserted into the grounding hub (13) in the region of the opening into the collecting space (32).

14. Assembly according to any one of claims 1 to 5, characterized in that The grounding hub (13) is fixed.

15. The assembly according to claim 1, characterized in that The component is a component for grounding the rotor shaft of an electric machine.

16. The assembly according to claim 1, characterized in that The grounding hub is conductively connected to the housing.

17. The assembly according to claim 9, characterized in that A rolling bearing is arranged between the grounding hub (13) and the shaft (7) to be grounded.

18. A transmission mechanism (40), characterized in that: The transmission comprises at least one shaft (7) which is grounded in accordance with an assembly according to any one of claims 1 to 17.

19. The transmission mechanism (40) according to claim 18, characterized in that: The transmission is a motor vehicle transmission.

20. An electric axle drive unit (1) for a motor vehicle, characterized in that A shaft (7) is provided, which is grounded in accordance with an assembly according to any one of claims 1 to 17.

21. An electric motor (50) comprising a stator (52) which is fixed in rotation relative to one another and a rotatable rotor (53), the rotor (53) being coupled to a rotor shaft (54), characterized in that: The rotor shaft (54) is grounded according to the assembly of any one of claims 1 to 17.

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