Slip ring for transmitting electrical current and for arrangement on a rotor shaft of an electric machine, and slip ring arrangement for transmitting current to a rotor of an electric machine

Abstract

The invention relates to a slip ring (1, 2) for transmitting electrical current and for arrangement on a rotor shaft (20) of an electric machine, characterized in that a cross-sectional profile is provided which reduces the mechanical profile rigidity at least in the region of the radial contact surfaces (3, 4) for fastening to a support (15). The invention also relates to a slip ring arrangement for transmitting current to a rotor of an electric machine, the slip ring arrangement having, for electrical sliding contact, at least one slip ring (1, 2) which is arranged on a support (15), wherein, in order to be arranged on a rotor shaft of an electric machine, the support (15) has at least one hub portion (21) which on the inner diameter has a surface contour (22, 23) by which, in order to be fastened to the outer diameter of the rotor shaft (20), the support (15) can be fitted thereon so as to make contact only in portions, such that free spaces (27, 26) are formed between the contact points (24, 25).

Description

[0001] Slip ring for electrical current transmission and arrangement on a rotor shaft of an electric machine and slip ring arrangement for current transmission to a rotor of an electric machine

[0002] The invention relates to a slip ring for electrical current transmission and its arrangement on a rotor shaft of an electric machine. The invention further relates to a slip ring arrangement for current transmission to a rotor of an electric machine.

[0003] From DE 10 2020 120 878 A1, a current-excited electric machine is known with a rotor and rotor winding that is rotatably mounted relative to a stator about a central axis of rotation. A slip ring assembly forms an electrical contact on a shaft element that is non-rotatably coupled to the rotor, and a connecting line electrically connects the rotor winding to the slip ring assembly.

[0004] CN 2 899 199 Y describes an integrated slip ring for a motor, consisting of an inner sleeve and a conductive ring arranged outside the inner sleeve. Three phases of the conductive ring are evenly distributed around the circumference outside the inner sleeve. One end of the conductive row is rigidly connected to each phase of the conductive rings in the radial central annular face of each phase of the conductive rings.

[0005] WO 2023 / 005 187 A1 describes a slip ring dome with three phases, comprising an inner shaft and an outer shaft. A plurality of the inner shaft transmission channels are arranged on the outer circular surface of the inner shaft. The outer shaft has a plurality of outer shaft transmission channels and a plurality of V-shaped grooves.

[0006] An electric machine comprising a stator and a rotor shaft, which carries at least several slip rings, is disclosed in DE 10 2019 120 802 A1. The slip rings are arranged in recesses of a slip ring carrier integrated into the rotor shaft. The rotor for an electric rotary machine described in EP 2 824 810 B1 comprises a shaft and a slip ring assembly pressed onto it, which has two slip rings that are insulated against a main body. The shaft is pressed into a press-fit section of a bore in the main body.

[0007] The invention is therefore based on the objective of proposing a slip ring and a slip ring arrangement of the aforementioned type, which reduce the stresses occurring in operation, in particular due to the heat generated at the sliding contact, in a carrier for arranging at least one slip ring on a rotor shaft of an electric machine.

[0008] The problem is solved by the features of claim 1. Further advantageous and claimed embodiments are described in the respective dependent claims, the description, and the drawings.

[0009] The problem according to the invention is solved by a slip ring arrangement for transmitting current to a rotor of an electric machine. The slip ring arrangement comprises a carrier and at least one slip ring arranged on the carrier for transmitting electrical current via a sliding contact. The carrier, for mounting on a rotor shaft of an electric machine, has at least one hub section with a surface contour on its inner diameter, allowing the carrier to be attached to the outer diameter of the rotor shaft only partially, such that gaps are formed between the contact points. At the contact points, the carrier is pressed onto the outer diameter of the rotor shaft with the inner diameter of the hub section in a flat, contact-like manner, such that the carrier can deflect and expand freely in the gaps where it does not contact the rotor shaft under loads occurring during operation.Accordingly, in areas where the support does not rest against the rotor shaft, it can flex and expand freely, particularly under thermal stress during operation, thereby reducing stress. This also results in the advantages described below.

[0010] In a preferred embodiment of the invention which is easy and inexpensive to manufacture, the free spaces are formed by small concave depressions distributed around the inner circumference on the inner diameter of the hub section.

[0011] Preferably, in order to avoid voltage peaks during operation, the recesses are connected tangentially at the transition to the contact points by a slight convex rounding, so that a continuous transition is achieved.

[0012] Preferably, the contact points and the recesses extend in the axial direction over the entire length of the hub section.

[0013] In a further development of the invention, the support can be pressed onto the rotor shaft at the contact points, with the inner diameter of the hub section at least partially in contact with the outer diameter. Accordingly, a good, rotationally rigid connection between the support and the rotor shaft can be achieved at these surface contact points.

[0014] Preferably, the contact points and free spaces are arranged alternately, evenly distributed around the inner circumference. This even distribution around the inner circumference ensures a correspondingly even distribution of the load on the beam.

[0015] Preferably, six contact points and six free spaces are arranged alternately one after the other, distributed around the inner circumference of the hub section of the support. An alternative design provides for three contact points and three free spaces arranged alternately one after the other, distributed around the inner circumference of the hub section of the support.

[0016] The torsional rigidity of the support arrangement on the rotor shaft can be individually adjusted to the operating and installation conditions by modifying the number and length of the contact points in the circumferential and axial directions. The magnitude of the stresses in the support, particularly those generated by thermal loads during operation, can be reduced by adjusting the number and size of the clearances.

[0017] The greater the length of the contact points, the better the load distribution and the greater the strength of the connection between the support and the rotor shaft. The greater the number of clearances, the better the support can deflect under load and the lower the stresses occurring in the support during operation.

[0018] In this way, the design of the surface contour of the hub section can be easily adapted to the operating and installation conditions, especially of the rotor shaft.

[0019] It is also conceivable to design the contact points on the hub section of the support beam to be flush. This maximizes the clearance for the beam to deflect under load, thereby minimizing the stresses occurring in the beam during operation. However, this minimizes the contact points to a mere line contact, which also reduces the strength of the connection between the beam and the rotor shaft.

[0020] In a further particularly preferred embodiment of the invention, the slip ring arrangement is designed with at least one slip ring as described above. This allows the advantages already mentioned for the proposed slip ring and the proposed slip ring arrangement to be combined. Accordingly, a slip ring for electrical current transmission and arrangement on a rotor shaft of an electric machine is proposed. It is provided that the slip ring is designed with a cross-sectional profile that reduces the mechanical profile stiffness, at least in the area of ​​the radial contact surfaces for mounting on a support, such that the slip ring exhibits lower resistance to strain and, in its installed position, is more easily deformable under thermal stress on the support, thus reducing the stresses generated in the support.

[0021] In this way, the slip ring offers lower structural resistance, or a lower section modulus, against strains, particularly in the radial direction, during operation, at least in the area of ​​the radial contact surfaces for mounting on the carrier. Consequently, the carrier can deform more readily under stresses, especially those caused by thermal stress, thus reducing the stresses generated within the carrier. This is particularly true if the carrier also acts as an electrical insulator and is made of a material with lower strength, especially plastic.

[0022] This allows for greater differences in the specific thermal expansion of the components interacting with the support, in particular the slip ring, the rotor shaft and the conductors for the electrical power supply of the rotor, thereby reducing costs and improving the function in operation.

[0023] In a preferred embodiment of the invention that is easy to manufacture, the slip ring forms a T-shaped cross-sectional profile with an axially extending T-leg and a radially extending T-leg arranged on the inner diameter of the same.

[0024] Preferably, radially inwardly oriented, annular contact surfaces are formed on both sides of the inner diameter of the connected radial T-leg for fastening to the support. This allows for a simple reduction of the radial wall thickness, particularly on the axial T-leg, and thus its resistance to radial elongation. Consequently, compared to a solid cross-section, it exhibits lower structural resistance, enabling the support to deform more freely, especially in the radially outward direction, during operation, particularly under thermal stress, and reducing the resulting stresses within the support.

[0025] Preferably, the axial T-leg forms a sliding contact surface on the outer diameter for electrical current transmission, and the radial T-leg forms an electrical connection for a current conductor for the electrical power supply of the rotor.

[0026] It is advantageous if, preferably, the radial T-leg forms two annular contact surfaces on its axial sides, oriented in an axially outward direction. This allows the slip ring to be fixed to a carrier on the radial T-leg in both axial directions. Preferably, the axial contact surfaces on the radial T-leg are planar.

[0027] It is also advantageous if the length of the radial T-leg is shorter than the length of the axial T-leg. This allows the radial installation space to be reduced to suit the installation conditions.

[0028] In a further preferred embodiment of the invention, the slip ring forms annular contact surfaces arranged in a V-shape on its inner circumference for attachment to a carrier. Preferably, a radial connection surface for a conductor is provided radially inside at the base of the V.

[0029] Preferably, two slip rings, each assigned to an electrical pole, are arranged on a tubular section of the carrier projecting towards the electrical sliding contact.

[0030] It is also advantageous if the carrier material is at least partially plastic and the slip rings are radially encapsulated in plastic at the contact surfaces for mounting on the tubular section. This allows for a particularly simple and cost-effective mounting of the slip ring to the carrier using plastic injection molding. The plastic also serves as an electrical insulator. Furthermore, the weight of the carrier can be reduced by using plastic, thus increasing its operational dynamics.

[0031] Preferably, the slip rings with the electrical connections are each connected to a current conductor integrated into the carrier and guided from the tubular section via two arms to an electrical connection on an annular section of the carrier for current transmission to a rotor winding of the electric machine.

[0032] Preferably, the carrier with the tubular section and the ring-shaped section and the arms can be attached to the rotor shaft in a rotationally fixed manner.

[0033] In a particularly simple and cost-effective manner, two slip rings for electrical connection to a rotor winding of the electric machine can be attached to the carrier on the rotor shaft, especially by press-fitting. Furthermore, this method allows for a particularly material-efficient and mass-reduced design of the carrier, which can further increase its operational dynamics.

[0034] Furthermore, the tubular section, due to its axial length, allows for greater electrical creepage distance isolation between the inner metal rings of the slip rings. The creepage distance isolation can be further increased by a suitable surface contour on the tubular section, or the annular section can be shortened accordingly while maintaining the same creepage distance isolation.

[0035] Furthermore, the slip rings, each connected to the tubular section of the carrier, form a pre-assembled modular unit with it in a particularly advantageous manner. The design of the tubular and annular sections, as well as the arms, allows for particularly easy adaptation to the installation conditions, especially on the rotor shaft of the electric machine. This is especially true when the carrier is manufactured by injection molding and can be easily and cost-effectively adapted to any rotor shaft shape.

[0036] Consequently, the proposed slip ring assembly, as a prefabricated module, can be flexibly designed and constructed for various rotor shafts as a standardized, cost-saving design with identical or largely identical components and a small number of parts, enabling particularly cost-effective series production. This applies especially to the slip rings of the slip ring assembly.

[0037] The proposed slip ring arrangement is particularly advantageous for use in a separately excited synchronous machine.

[0038] Further claimed features of the invention will become apparent from the following description and from the drawings, which further explain the present invention. The drawings show:

[0039] Figure 1 shows a slip ring according to the invention for current transmission and arrangement on a rotor shaft of an electric machine in a perspective view in a first embodiment.

[0040] Figure 2 shows the slip ring in cross-section,

[0041] Figure 3 shows a slip ring according to the invention for current transmission and arrangement on a rotor shaft of an electric machine in a cross-section in a second embodiment.

[0042] Figure 4 shows a slip ring arrangement according to the invention for current transmission to a rotor of an electric machine in a longitudinal section.

[0043] Figure 5 shows the slip ring arrangement in a perspective view, Figure 6 shows the slip ring arrangement with a hub section on a rotor shaft in an axial view in a first embodiment,

[0044] Figure 7 shows an enlarged section of Figure 6,

[0045] Figure 8 Figure 7 without the rotor shaft,

[0046] Figure 9 shows the slip ring arrangement with a hub section on a rotor shaft in an axial view in a second embodiment.

[0047] Figure 10 shows an enlarged section of Figure 9,

[0048] Figure 11 Figure 10 without the rotor shaft.

[0049] The figures illustrate various views and embodiments of a slip ring according to the invention for electrical current transmission and arrangement on a rotor shaft of an electric machine. The figures further illustrate various views and embodiments of a slip ring arrangement according to the invention for current transmission to a rotor of an electric machine.

[0050] The slip ring 1, 2, shown in two embodiments in Figures 1 to 3, has a cross-sectional profile that is simply symmetrical about an indicated axis of symmetry 14 in the area of ​​the radial contact surfaces 3, 4 for mounting on a carrier (Figures 4 to 11). The carrier 15 serves for mounting on a rotor shaft 20 and preferably also for electrical insulation (Figures 4 to 11). Axial contact surfaces 5, 6 are provided for further mounting on the carrier 15.

[0051] A first embodiment according to Figures 1 and 2 shows the slip ring 1, 2 with a T-shaped cross-sectional profile comprising an axially extending T-leg 7 and a radially extending T-leg 8 integrally connected to the inner diameter at its axial center. The axial T-leg 7, with a sliding contact surface 9 on its outer diameter, serves for current transmission in sliding contact with brushes of a current transmission system, while the radial T-leg 8 provides an electrical connection 10 on its radial inner side for a conductor 18, 19 to supply the rotor winding of the electric machine. The electrical connection 10 is designed on the radial end face of the free radially inner end of the radial T-leg 8 as an annularly circumferential contact surface for a conductor, oriented in a radially inward direction.

[0052] The axial T-leg 7 forms two radially inwardly oriented, circumferentially circumferential contact surfaces 3, 4 on both sides of the connected radial T-leg 8 on its inner diameter for mounting on a support 15 for arrangement on the rotor shaft 20 (Figures 4 to 11). On the radial T-leg 8, two axially outwardly oriented, circumferentially circumferential planar contact surfaces 5, 6 are provided on the axial sides, each allowing mounting on the support 15 in both axial directions.

[0053] The design of the slip ring 1, 2 with the T-shaped cross-sectional profile allows the axial T-leg 7 to have a reduced wall thickness S compared to a solid cross-section, thereby reducing the profile stiffness of the slip ring 1, 2 in the area of ​​the radial contact surfaces 3, 4. Consequently, the slip ring 1, 2 exhibits lower structural resistance or a lower section modulus with respect to radial strain, particularly due to thermal stress during operation.

[0054] Consequently, the support 15, which rests against the radial contact surfaces 3, 4 of the axial T-leg 7 for fastening in the assembled state, can more easily deform radially outwards in the main direction of strain during operation, particularly under stresses caused by thermal stress, thus reducing the stresses generated in the support 15. At the same time, the axial fixation of the slip ring 1, 2 with the axial contact surfaces 5, 6 of the radial T-leg 8 on the support 15 remains unchanged. This is especially true if, as here, the support 15 is also designed as an electrical insulator and is made of a material with lower strength, particularly plastic.

[0055] The design according to the invention allows for greater differences in the specific thermal expansion of the components interacting with the carrier, in particular the slip ring 1, 2, the rotor shaft 20 and the conductors 18, 19 for current transmission to the rotor 20 (Figures 4 to 11), in order to reduce costs and improve the function in operation.

[0056] The slip ring 1, 2 shown in a second embodiment in Figure 2 has contact surfaces 11, 12 arranged in a V-shape on its inner circumference for attachment to the carrier 15. These contact surfaces converge radially inwards and are arranged in a continuous, oblique annular pattern. The V-shaped arrangement allows for a reduction in the mean wall thickness D of the slip ring 1, 2, resulting in lower structural resistance and a lower section modulus against radial strain. This allows the carrier 15, which rests against the oblique contact surfaces 11, 12 for attachment in the mounted state, to deform more easily under load, thus reducing the stresses generated in the carrier 15. An electrical connection 13 is provided on the inner diameter of the radially inward-oriented base of the V, serving as a radial connection surface for a conductor 18, 19.

[0057] The slip ring assembly shown in Figures 4 to 11 comprises two slip rings 1, 2, each assigned to an electrical pole, and a carrier 15, which is arranged on a rotor shaft 20 of the electric machine (not shown). The slip rings 1, 2 are arranged coaxially one behind the other on a tubular section 17 of the carrier 15 along its longitudinal axis 16. As already described above, they are each connected to the tubular section 17 of the carrier 15 by means of the axial T-leg 7 and the radial T-leg 8, respectively, and are non-rotatably connected to the carrier. The carrier 15 serves to electrically insulate the slip rings 1, 2 and the conductors 18, 19 guided in the carrier. It also serves to mount the assembly on a rotor shaft 20 of an electric machine (Figures 6 and 9).The slip rings 1, 2 each project freely radially with their sliding contact surface 9 on the outer diameter of the axial T-leg 7 on the tubular section 17 to form an electrical sliding contact (Figures 4 and 5). The radial T-legs 8 are each electrically connected to a conductor 18, 19 embedded in the support 15 as a busbar for current transmission to the rotor by means of a material connection, for example by welding or soldering, via the electrical connection 10 formed at the end face of their radially inner end.

[0058] The carrier 15 is made of plastic, which also serves as an electrical insulator. The slip rings 1, 2 are each overmolded with plastic at the radial contact surfaces 3, 4 of the axial T-legs 7 and at the axial contact surfaces 5, 6 of the radial T-legs 8 for a material-bonded attachment to the tubular section 17 of the carrier 15 (Figure 4). In this way, the carrier 15 with the attached slip rings 1, 2 and the embedded conductors 18, 19 can be manufactured by injection molding in a single operation.

[0059] This allows for a particularly simple and cost-effective mounting of the slip rings 1, 2 with the T-arms 7, 8 onto the carrier 15 by means of plastic injection molding. Additional components are unnecessary. Furthermore, the weight of the carrier 15 can be further reduced by using plastic, thus increasing its operational dynamics.

[0060] For mounting on the rotor shaft of an electric machine, the support 15 forms a hub section 21 radially inside the tubular section 17 (Figures 4 to 11). Figures 6 to 11 show, in axial plan view, two different embodiments of surface contours 22, 23 on the inner circumference of the hub section 21, with each of which the support 15 can be attached to the outer diameter of the rotor shaft 20 only partially, with contact points 24, 25. The contact points 24, 25 formed on the surface contour 22, 23 define spaces 26, 27 between them for expansion of the support 15 under load. The contact points 24, 25 and the spaces 26, 27 are thus arranged alternately one behind the other, evenly distributed in the circumferential direction, on the inner circumference of the hub section 21 (Figures 6 to 11).The contact points 24, 25 and the free spaces 26, 27 form a surface structure on the inner circumference of the hub section 21, which extends over the entire axial length of the tubular section 17 of the support 15 (Figure 4).

[0061] In Figures 6 to 11, the clearances 26, 27 and the concave recesses forming them on the inner diameter of the hub section 21 are shown enlarged for illustration. The recesses 26, 27 can be modified to suit the operating conditions and installation circumstances in order to adjust the size of the clearances. In particular, they can be formed by a concave indentation on the inner diameter of the hub section 21, especially with a smaller radial depth.

[0062] The clearances 26, 27 are formed by slight concave depressions, in particular slight indentations, distributed around the inner circumference of the hub section 21. At the contact points 24, 25, the support 15 with the inner diameter of the hub section 21 is pressed flat against the outer diameter of the rotor shaft 20 (Figure 4).

[0063] In order to avoid voltage peaks in particular during operation, the recesses limiting the free spaces 26, 27 are each connected tangentially at the transition to the contact points 24, 25 by a slight convex rounding 28, 29, so that a continuous transition is achieved (Figures 6 to 11 ).

[0064] Accordingly, the support 15 can deflect and expand freely in the spaces 26, 27, where it does not bear against the rotor shaft 20, under loads occurring during operation. This reduces the stresses in the support 15 caused by the thermal loads occurring during operation, particularly those resulting from the electrical sliding contact of the slip rings 1, 2. An embodiment optimized with respect to the distribution of the loads occurring during operation, particularly the thermal loads on the support 15, comprises, as shown in a first embodiment in Figures 4 to 8, a surface contour 22 with six contact points 24 evenly distributed around the inner circumference of the hub section 21 of the support 15. These contact points define six circumferential spaces 26, each formed between them by recesses on the inner diameter of the hub section 21.

[0065] In contrast, the second embodiment shown in Figures 9 to 11 is optimized with regard to the torsional strength of the support 15 arranged on the rotor shaft 20. For this purpose, a surface contour 23 is provided with contact points 25 evenly distributed over the inner circumference of the hub section 21 of the support 15, which define three clearances 27 in the circumferential direction formed between them by recesses on the inner diameter.

[0066] In the first embodiment according to Figures 6 to 8, the larger number of free spaces 26 promotes the deflection of the support 15 under load, thereby reducing the stresses occurring in the support 15 during operation due to the load.

[0067] In contrast, in the second embodiment according to Figures 9 to 11, the length of the contact points 25 on the rotor shaft 20 is increased in the circumferential direction, thereby achieving a greater strength of the connection of the support 15 with the rotor shaft 20.

[0068] The torsional rigidity of the arrangement of the support 15 on the rotor shaft 20 can be individually adjusted to the operating and installation conditions by the number and length of the contact points 24, 25 in the circumferential and axial directions. The magnitude of the stresses in the support, particularly those generated by thermal loads during operation, can be reduced by the number and size of the clearances 26, 27. The greater the circumferential length of the contact points 24, 25, the better the load distribution and the greater the strength of the connection between the support 15 and the rotor shaft 20. The greater the number of clearances 26, 27, the better the support 15 can deflect under load and the lower the stresses occurring in the support 15 during operation.

[0069] According to Figures 4 and 5, the support 15 has, in addition to the tubular section 17, an annular section 30. The sections 17 and 30 are arranged one behind the other along the longitudinal axis 16. The sections 17 and 30 are connected to each other by two arms 31 and 32, offset by 180° and thus diametrically opposed. In this way, the support 15 can be manufactured in a particularly material-saving and mass-reduced manner, which can increase its operational dynamics.

[0070] The tubular section 17, which accommodates the slip rings 1 and 2, has a significantly greater axial length than the annular section 30. This allows for greater electrical creepage distance insulation between the slip rings 1 and 2 in the tubular section 17. As shown, for a given axial length, this insulation can be further increased by a surface contour 33 with a profile formed in longitudinal section (Figure 4) by expansions on the outer diameter. In contrast, the annular section 30 has a larger inner diameter than the tubular section 17.

[0071] The support 15 can be axially mounted on the respective outer diameter of the rotor shaft with the respective inner diameter of the tubular section 17 and the annular section 30 and can be easily pressed on for fastening, preferably in a transverse press fit.

[0072] The arms 31, 32, extending axially from the outer diameter of the tubular section 17, engage with their inner surfaces in corresponding recesses on the outer diameter of the rotor shaft, thus enabling them to be fitted onto the shaft in a form-fitting and rotationally fixed manner. At their end sections facing the annular section 30, the arms 31, 32 are angled obliquely radially outward toward the inner diameter of the annular section 30 and are connected to it. The arms 31, 32 form guide surfaces 34, 35 on the inner surfaces of these end sections, each acting as a chamfer to facilitate assembly and fitting onto the rotor shaft 20.

[0073] Further guide surfaces 36, serving as an assembly aid for mounting onto the rotor shaft 20, are each formed as a chamfer on the hub section 21 of the tubular section 17. They are located at the axially inner end of the contact points 24, 25, as shown in Figure 4 only for the first embodiment according to Figures 4 to 8.

[0074] The conductors 18, 19 each extend from the electrical connection 10, 13 at the slip rings 1, 2 on the tubular section 17 via the arms 31, 32 to the annular section 30. They extend radially outwards at an angle along this section and their free ends protrude from an expanded end section of the second tubular section 30 at the outer diameter, forming an electrical connection 37, 38 for the rotor winding of the electric machine.

[0075] In this way, the slip rings 1, 2 can be connected to the rotor windings of the electric machine via the current conductors 18, 19 guided by the arms 31, 32 and the electrical terminals 37, 38. This allows the electric current to be transferred from a power source via the sliding contact to the sliding contact surface 9 of one slip ring 1, 2 and via the respective current conductor 18, 19 connected to the latter and via the respective electrical terminal 37, 38 to the rotor windings. From there, the electric current flows back via the other electrical terminal 37, 38 and the other current conductor 18, 19 to the other slip ring 1, 2 and via the sliding contact surface 9 and the sliding contact in a closed circuit with the power source.The slip rings 1, 2, each arranged on the first tubular section 17 of the carrier 15, form a pre-assembled modular unit with the carrier 15, which can be easily pressed onto the rotor shaft 20 of the electric machine for fastening.

[0076] Due to the design of the tubular section 17 and the annular section 30, in particular by their inner diameter, as well as the arms 31, 32, the support 15 can be adapted particularly easily to the installation conditions, especially to the rotor shaft of the electric machine.

[0077] In this way, the proposed slip ring assembly can be manufactured as a prefabricated module with flexible design and construction, resulting in a standardized, cost-saving design with consistently identical or largely identical components and a small number of parts, enabling particularly cost-effective series production. This applies especially to slip rings 1 and 2 of the slip ring assembly.

[0078] List of reference signs

[0079] Slip ring, radial contact surface, axial contact surface, axial T-leg, radial T-leg, sliding contact surface, electrical connection, inclined contact surface, inclined contact surface, electrical connection, axis of symmetry, support, longitudinal axis, tubular section, conductor, conductor, rotor shaft, hub section

[0080] Surface contour, surface structure Surface contour, surface structure Application point Application point

[0081] Free space, concave depression Free space, concave depression Convex curve, transition Convex curve, transition Ring-shaped section 31 Arm

[0082] 32 Arm

[0083] 33 Surface contour

[0084] 34 Guide surface

[0085] 35 guide surface

[0086] 36 guide surface

[0087] 37 electrical connection

[0088] 38 electrical connection

[0089] S wall thickness

[0090] D average wall thickness

Claims

Patent claims 1. Slip ring arrangement for current transmission to a rotor of an electric machine, comprising at least one slip ring (1, 2) for electrical sliding contact, which is arranged on a carrier (15), wherein the carrier (15) for arrangement on a rotor shaft of an electric machine has at least one hub section (21) with a surface contour (22, 23) on its inner diameter, with which the carrier (15) can be attached to the outer diameter of the rotor shaft (20) only in partial contact, such that spaces (26, 27) are formed between the contact points (24, 25), wherein at the contact points (24, 25) the carrier (15) is pressed flat against the outer diameter of the rotor shaft (20) with the inner diameter of the hub section (21), such that the carrier (15) in the spaces (26, 27), where it does not contact the rotor shaft (20), is subjected to loads occurring during operation. can evade and expand freely.

2. Slip ring arrangement according to claim 1 , characterized in that the free spaces (26, 27) are formed by concave recesses on the inner diameter of the hub section (21 ).

3. Slip ring arrangement according to one of claims 1 or 2, characterized in that the carrier (15) can be pressed onto the outer diameter of the rotor shaft (20) at least partially in a planar position at the contact points (24, 25) with the inner diameter of the hub section (21).

4. Slip ring arrangement according to one of claims 1 to 3, characterized in that three or six contact points (24, 25) and free spaces (26, 27) are provided, which are arranged alternately one behind the other and are evenly distributed over the inner circumference of the hub section (21) of the carrier (15).

5. Slip ring arrangement according to one of claims 1 to 4, characterized in that at least one slip ring (1, 2) for electrical current transmission and arrangement on a rotor shaft (20) of an electric machine is provided with a cross-sectional profile reducing the mechanical profile stiffness at least in the area of ​​the radial contact surfaces (3, 4) for attachment to a support (15), such that the slip ring (1, 2) has a lower resistance to strain and, in the installed position of the support (15), is more easily deformable under thermal stress and the stresses generated in the support (15) are reduced.

6. Slip ring arrangement according to one of claims 1 to 5, characterized in that at least one slip ring (1, 2) for electrical current transmission and arrangement on a rotor shaft (20) of an electric machine is provided with a T-shaped cross-sectional profile having an axially extending T-leg (7) and a radially extending T-leg (8) arranged on the inner diameter thereof, wherein the axial T-leg (7) has annular contact surfaces (3, 4) oriented radially inwards on the inner diameter and a sliding contact surface (9) for current transmission on the outer diameter and the radial T-leg (8) forms an electrical connection (10) for a current conductor (18, 19).

7. Slip ring arrangement according to one of claims 1 to 5, characterized in that on the inner circumference of at least one slip ring (1 , 2) for electrical current transmission and arrangement on a rotor shaft (20) of an electric machine for attachment to the support (15) annular contact surfaces (11 , 12) are arranged in cross-section in a V-shape and a radial connection surface (13) for a current conductor (18, 19) is provided radially inside at the base of the V.

8. Slip ring arrangement according to one of claims 1 to 7, characterized in that two slip rings (1 , 2) each assigned to an electrical pole are each mounted on a tubular section (17) of the carrier (15) on this above are arranged to form an electrical sliding contact, wherein the carrier (15) is at least partially made of plastic and the slip rings (1 , 2) are overmolded with plastic radially inside contact surfaces (3, 4, 5, 6) for attachment to the tubular section (21 ).

9. Slip ring arrangement according to claim 8, characterized in that the slip rings (1, 2) are radially internally connected with electrical connections (10, 13) and each with a current conductor (18, 19) integrated into the carrier (15) and guided from the tubular section (17) via two arms (31, 32) to an annular section (30) of the carrier (15) Power transmission to a rotor winding of the electric machine is connected, wherein the carrier (15) with the aforementioned sections (17, 30) and the arms (31, 32) can be attached to the rotor shaft in a rotationally fixed manner.

Images