Current transmission device for rotor of electric machine, and electric machine

Abstract

The utility model relates to a current transmission device (1) used for a rotor (2) of a motor (3), especially the motor (3) in a driving system (4) of an electrically-driven motor vehicle, the current transmission device comprises an annular disc (6), the annular disc at least partially surrounds a rotor shaft (7) of the rotor (2) on the circumference, and the current transmission device is positioned in an anti-rotation manner relative to the rotor shaft (7). At least one electrical contact (8) is arranged on the annular disc (6), which is loaded with a spring force in the radial direction by means of a spring element (9) and is guided in each case in a linear movement in the direction of the rotor shaft (7) in a guide (10), the contact element (8) rests against at least one circumferentially extending conductor track (11) of the rotor shaft (7) in an electrically conductive manner, and the one or more guide elements (10) are integrally formed with the annular disc (6).

Description

Technical Field

[0001] The utility model relates to a current transmission device for a rotor of an electric machine, in particular an electric machine in a drive train of an electrically driven motor vehicle. The current transmission device comprises an annular disk which at least partially surrounds the rotor shaft of the rotor in the circumferential direction, and the annular disk is positioned anti-rotationally relative to the rotor shaft, so that the rotor shaft rotates relative to the annular disk. At least one electrical contact is arranged on the annular disk. The electrical contacts are respectively loaded with a spring force in the radial direction by means of spring elements and are respectively guided linearly movable in guides in the direction towards the rotor shaft, and the contacts conductively abut against at least one conductor track extending in the circumferential direction on the rotor shaft. Background Art

[0002] A commutator motor generally consists of a stator and a rotor that can rotate relative to the stator. The stator is implemented as a hollow cylinder in a radial flux motor. The stator forms a magnetic field by means of permanent magnets in the case of a permanent magnet excited brushed motor or by means of a main pole winding or an excitation winding in the case of a series-wound motor or a shunt-wound motor. The rotor can move in the magnetic field. For this purpose, one or more coils or rotor windings are usually provided on the rotor, which are connected to a power supply via a commutator or a pole changer. If the coils are energized, a magnetic field is generated, and the magnetic field combines with the magnetic field of the stator to generate torque.

[0003] During rotation, the commutator changes the polarity of the rotor windings so that current always flows through these rotor windings in a direction transverse to the stator magnetic field. This change in polarity is achieved via so-called sliding contacts or brushes. The brushes are arranged in the commutator motor such that the brushes sequentially contact the respective commutator contacts when the commutator rotates.

[0004] In addition to DC motors, separately excited synchronous motors are also known, which are also highly efficient without rare earth magnets. In a separately excited synchronous motor, energy is usually transferred to the rotor by means of a slip ring system.

[0005] For this purpose, the brushes are usually accommodated in a brush holder, and the brush holder guides the brushes so that they can move linearly in the radial direction towards the shaft of the rotor. Such a carbon brush holder usually consists of multiple components. For example, multiple guiding parts are connected to the substrate in a form-fitting or material-connected manner. The additional components lead to an increase in material and installation costs, which is usually not desirable. In addition, it must be ensured that the connections of the different components of the brush holder do not loosen inadvertently during operation, so as to ensure that the carbon brushes are reliably guided throughout the service life of the commutator engine. Summary of the Utility Model

[0006] The object of the present utility model is thus to avoid or at least mitigate the known disadvantages in the prior art and to provide a current transmission device for the rotor of an electric machine, which current transmission device is optimized in terms of manufacturing technology and ensures a high degree of operating reliability.

[0007] This object is achieved by a current transmission device for the rotor of an electric machine, in particular an electric machine in the drive train of an electrically drivable motor vehicle. The current transmission device comprises an annular disk which at least partially surrounds the rotor shaft of the rotor in the circumferential direction, and the annular disk is positioned anti-rotationally relative to the rotor shaft, so that the rotor shaft rotates relative to the annular disk. At least one electrical contact element is arranged on the annular disk. The contact elements are each loaded with a spring force in the radial direction by means of a spring element and are each guided linearly movable in a guide element in the direction towards the rotor shaft, and the contact elements conductively abut against at least one conductor track extending in the circumferential direction of the rotor shaft, wherein one or more guide elements are integrally formed with the annular disk.

[0008] The advantage achieved thereby is that the guide elements are already integrated in the annular disk, which is particularly advantageous in terms of manufacturing technology. In particular, the guide elements are formed by non-cutting deformation of at least one section of the annular disk.

[0009] Preferably, a plurality of contact elements are arranged on the current transmission device. Most preferably, three contact elements are arranged on the current transmission device.

[0010] According to a most preferred embodiment of the present utility model, it can be provided that lugs are released from the annular disk, and the lugs are used as guide elements for the contact elements after two bends. For this purpose, it can also be preferred herein that the two bent lugs are connected in a form-fitting, force-transmitting or material-connecting manner on the upper side. In addition, it is also preferred that the two lugs are implemented asymmetrically, which can be preferred for reasons of structural space.

[0011] The annular disk can be configured to be circumferentially closed, but can also be in the form of an annular segment.

[0012] First, the individual elements of the subject matter claimed in the present utility model are explained in their interrelationship or in the order in which they are mentioned in the claims, and particularly preferred design embodiments of the subject matter of the present utility model are described below.

[0013] The rotor is the rotatable part of the electric machine. The rotor particularly includes a rotor shaft. The rotor shaft can be implemented as hollow, which can save weight on the one hand and can supply lubricant or coolant to the rotor body on the other hand.

[0014] The electric machine can in particular be implemented as a separately excited synchronous motor.

[0015] The current transmission device can also be designed as a shaft grounding part for the rotor shaft, so that current can be output from the rotor shaft.

[0016] The electric machine can in particular be configured as a rotating electric machine. The rotating electric machine can in particular be configured as a radial flux electric machine. Here, the radial flux electric machine is characterized in that the magnetic field lines extend in the radial direction in the air gap formed between the rotor and the stator. The gap between the rotor and the stator is called the air gap. In the radial flux electric machine, this is an annular gap in cross-section, and the radial width of the annular gap corresponds to the distance between the rotor body and the stator body.

[0017] The electric machine is in particular used in the drive train of a motor vehicle with a hybrid drive or a fully electric drive. In particular, the dimensions of the electric machine are designed such that the vehicle speed can reach more than 50 km / h, preferably more than 80 km / h, in particular more than 100 km / h. Particularly preferably, the electric motor has a power of more than 30 kW, preferably more than 50 kW, in particular more than 70 kW. It is also preferred that the electric machine provides a rotational speed of more than 5000 revolutions per minute, particularly preferably more than 10000 revolutions per minute, and very particularly preferably more than 12500 revolutions per minute.

[0018] The motor vehicle in the present application is a land vehicle that moves by mechanical power and is not dependent on a track. The motor vehicle can for example be selected from: passenger car (PKW), truck (LKW), scooter, light vehicle, motorcycle, bus (KOM) or tractor.

[0019] The contact element can for example be an electric carbon brush. Particularly preferably, the contact element is a solid block made of a conductive material.

[0020] Advantageous designs of the present utility model are given in the dependent claims. The features listed separately in the dependent claims can be combined with each other in a technically meaningful manner and can define other designs of the present utility model. In addition, the features given in the claims are explained and described in detail in the description, in which other preferred designs of the present utility model are shown.

[0021] According to an advantageous design of the present utility model, it can be provided that the annular disk is formed from a plate member. The advantage of this design is that the guide member can be made from the plate member in a particularly simple manufacturing technique.

[0022] According to another preferred improvement of the present utility model, it can also be provided that lug-shaped sections formed by deformation are arranged on the annular disk, and the lug-shaped sections extend out of the plane of the annular disk and form a guide member for the electrical contact element. Thereby, it can be achieved that the guide member can for example have at least two parallel extending sections, which allows good guiding of the contact element on both sides.

[0023] Furthermore, according to an equally advantageous design of the present utility model, it can be arranged that the lug-shaped sections forming the guide each have a rectangular basic shape, and the basic shapes each have a section extending out of the plane of the annular disk by deformation and a section with a free end extending parallel to the plane of the annular disk. The advantageous effect of this design is that the contact can be guided in a defined manner along the circumference thereby.

[0024] According to another particularly preferred embodiment of the present utility model, it can be arranged that the free ends of the lug-shaped sections are fastened to each other at least in the circumferential direction, especially in a form-fitting manner. In particular, the following effect can be achieved thereby, that is, the provided guide can be cost-effective in terms of manufacturing technology and shape-stable during operation.

[0025] In addition, the present utility model can also be improved in such a way that a dovetail-shaped connection is arranged on the free end of the first lug-shaped section, and the dovetail-shaped connection engages into a corresponding groove on the free end of the second lug-shaped section. The advantage of this design is that a particularly cost-effective implementation can be achieved in terms of manufacturing and assembly technology thereby.

[0026] In an equally preferred variant of the present utility model, it can also be arranged that the annular disk has a circular opening penetrated by the rotor shaft, and at the opening, there are lug-shaped sections forming the guide extending tangentially relative to the opening.

[0027] It can also be advantageous to improve the present utility model in such a way that the contact and / or the guide are basically formed identically, so that further cost advantages can be achieved through the height consistency.

[0028] The object of the present utility model is also achieved by a motor including a current transmission device.

[0029] Finally, the object of the present utility model is also achieved by a method for manufacturing a current transmission device for a rotor of a motor, especially a motor in the drive train of an electrically drivable motor vehicle. The method includes the following steps:

[0030] · Providing an annular disk that can at least partially surround the rotor shaft of the rotor in the circumferential direction,

[0031] · Stamping out lug-shaped sections from the annular disk,

[0032] · Bending the lug-shaped sections so that the lug-shaped sections extend out of the plane of the annular disk and thus form a guide for the electrical contact,

[0033] · Placing the electrical contact into the guide. Description of the Drawings

[0034] The present utility model will be explained in more detail below with reference to the accompanying drawings, without limiting the general idea of the present utility model.

[0035] The accompanying drawings show:

[0036] Figure 1 A schematic axial sectional view of an electric machine with a current transmission device is shown,

[0037] Figure 2 A schematic perspective view of a commutator of an energizable rotor is shown,

[0038] Figure 3 A perspective view of an annular disk of the current transmission device and a plurality of guides configured on the annular disk is shown,

[0039] Figure 4 An annular disk of the current transmission device and a plurality of lug-shaped sections are shown, and the lug-shaped sections have not been deformed from the plane of the annular disk,

[0040] Figure 5 A schematic block diagram of a motor vehicle with an electric machine is shown,

[0041] Figure 6 A schematic view of a rotor of a separately excited synchronous electric machine is shown,

[0042] Figure 7 A perspective view of a second embodiment of an annular disk of the current transmission device and a plurality of guides configured on the annular disk is shown,

[0043] Figure 8 A perspective view of a third embodiment of an annular disk of the current transmission device and a plurality of guides configured on the annular disk is shown,

[0044] Figure 9 A schematic axial sectional view of an embodiment of a current transmission device having two axially spaced annular disks is shown. Detailed Embodiment

[0045] Figure 1 A current transmission device 1 for a rotor 2 of an electric machine 3 configured as a radial flux electric machine is shown, in particular the electric machine 3 in a drive train 4 of an electrically drivable motor vehicle 5, as exemplarily shown in Figure 5 as shown by way of example.

[0046] The current transmission device comprises an annular disk 6 which circumferentially surrounds a rotor shaft 7 of the rotor 2 and is positioned in a rotationally fixed manner relative to the rotor shaft 7, so that the rotor shaft 7 rotates relative to the annular disk 6. For this purpose, the annular disk 6 is connected in a rotationally fixed manner to a non-rotatable component of the electric machine 3. A plurality of electrical contacts 8 are arranged on the annular disk 6, which are each loaded with a spring force in the radial direction by means of a spring element 9 and are each linearly displaceably guided in a guide 10 in the direction toward the rotor shaft 7, in such a way that the contact 8 rests slidably against the inner wall of the guide 10.

[0047] As per Figure 2 As shown, the contact element 8 bears in an electrically conductive manner against at least one conductor track 11 extending in the circumferential direction of the rotor shaft 7. Figure 2 In the embodiment shown, two half-shell conductor tracks 11 form the commutator 19 of the DC motor. For use in a separately excited synchronous motor, the conductor tracks 11 are closed on the circumference, i.e., annular, or only one annular conductor track 11 can be constructed on the rotor 2. This structure is Figure 6 It should be understood that the current transmission device 1 can be used not only in a DC motor but also in a separately excited synchronous motor.

[0048] The guide 10 is formed integrally with the annular disk 6. Figure 3 . The annular disk 6 is formed from a sheet metal part. Lug-shaped sections 13, 14 formed by deformation are arranged on the annular disk 6, which extend from the plane of the annular disk 6 and thus form a guide 10 for the electrical contact 8. The lug-shaped sections 13, 14 forming the guide 10 each have a rectangular basic shape, which each has a section 15 extending from the plane of the annular disk 6 by deformation and a section 16 extending parallel to the plane of the annular disk 6 with a free end 20.

[0049] The free ends 20 of the lug-shaped sections 13, 14 are fixed to each other in a form-fitting manner at least in the circumferential direction. To this end, a dovetail-shaped connection 17 is arranged at the free end of the first lug-shaped section 13, which engages in a corresponding groove 18 at the free end of the second lug-shaped section 14.

[0050] The annular disk 6 also has a circular opening 12, through which the rotor shaft 7 extends, and at which lug-like sections 13, 14 are formed which extend tangentially to the opening and form the guide element 10. In the exemplary embodiment shown, the contact element 8 and the guide element 10 are substantially identically formed.

[0051] The annular disk 6 and its guide 10 can be produced, for example, by the method described below to produce a current transmission device 1 for a rotor 2 of an electric machine 3 .

[0052] First, an annular disk 6 is provided, which can at least partially surround the rotor shaft 7 of the rotor 2 in the circumferential direction. Then, lug-shaped sections 13, 14 are punched out from the annular disk 6. This manufacturing state is shown in Figure 4 .

[0053] Then, the lug-shaped sections 13, 14 are bent such that the lug-shaped sections extend out from the plane of the annular disk 6 and thus form guides 10 for the electrical contact elements 8, as shown in Figure 3 . Next, the electrical contact elements 8 can be inserted into the guides 10.

[0054] In Figure 7 , another embodiment of the annular disk 6 is shown, in which the free ends of the section 16 do not contact on the end side and thus form a gap, which extends radially substantially with respect to the circular opening 12 of the annular disk 6. Thereby, the weight of the annular disk 6 can be further optimized and at the same time sufficient and good guidance of the contact elements 8 can also be achieved. The scheme for forming another weight-optimized embodiment of the annular disk 6 is shown in Figure 8 , in which the radially outer section around the guide 10 is completely removed and the guide only has a radially extending connecting structure in the form of a connecting portion with the annular disk 6.

[0055] Figure 9 A schematic axial sectional view of an embodiment of the current transmission device 1 having two axially spaced annular disks 6, 26 is shown. In this case, the first annular disk 6 and the second annular disk 26 are arranged on a common holding plate 21, which is preferably formed of a non-conductive material. The holding plate 21 is also annularly configured, and the rotor shaft 7 passes through the holding plate. Since the annular disks 6, 26 are arranged on the holding plate 21, a member is formed through which current can be transmitted to or output from the rotor shaft 7 via the annular disks 6, 26, the electrical conductors 23 and the contact elements 8, which is indicated by the + / − signs on the electrical conductor 22.

[0056] In the present application, the terms "radial", "axial", "tangential" and "circumferential direction" always refer to the rotational axis of the rotor of the electric machine. The terms "left", "right", "up", "down", "above" and "below" are only used herein to illustrate which region of the current drawings described in the text. Subsequent embodiments of the present invention can also be arranged differently. In addition, the present invention is not limited to the embodiments shown in the drawings. Therefore, the foregoing description is not restrictive but is regarded as explanatory. The following claims should be understood such that the recited features exist in at least one embodiment of the present invention. This does not exclude the existence of other features. If the claims and the foregoing description define "first" and "second" features, then this name is used to distinguish two features of the same type and not to determine a hierarchical order.

[0057] List of reference numerals

[0058] 1 Current transmission device

[0059] 2 Rotor

[0060] 3 Electric machine

[0061] 4 Drive train

[0062] 5 Motor vehicle

[0063] 6 Annular disk

[0064] 7 Rotor shaft

[0065] 8 Contact

[0066] 9 Spring element

[0067] 10 Guide

[0068] 11 Conductor track

[0069] 12 Opening

[0070] 13 Section

[0071] 14 Section

[0072] 15 Section

[0073] 16 Section

[0074] 17 Connection

[0075] 18 Slot

[0076] 19 Commutator

[0077] 20 End

[0078] 21 Retaining plate

[0079] 22 Electric conductor

[0080] 23 Electric conductor

[0081] 26 Annular disk

Claims

1. A current transmission device (1) for a rotor (2) of an electric motor (3), the electric motor (3) being an electric motor (3) in a drive train (4) of an electrically driven motor vehicle (5), the current transmission device comprising an annular disk (6) which at least partially surrounds a rotor shaft (7) of the rotor (2) in the circumferential direction and is positioned in a rotationally fixed manner relative to the rotor shaft (7), so that the rotor shaft (7) rotates relative to the annular disk (6), wherein at least one electrical contact (8) is arranged on the annular disk (6), the electrical contact being loaded with a spring force in the radial direction by means of a spring element (9) and being guided linearly displaceably in a guide (10) in the direction of the rotor shaft (7), and the contact (8) being in conductive contact with at least one conductor track (11) extending on the circumference of the rotor shaft (7), characterized in that The guide element or elements (10) are formed integrally with the annular disk (6).

2. The current transmission device (1) according to claim 1, characterized in that The annular disk (6) is made of a plate.

3. The current transmission device (1) according to claim 1 or 2, characterized in that: Lug-shaped sections (13, 14) are arranged on the annular disk (6) by deformation, extending out of the plane of the annular disk (6) and forming guides (10) for electrical contacts (8).

4. The current transmission device (1) according to claim 3, characterized in that The lug-shaped sections (13, 14) forming the guide (10) each have a rectangular basic shape, each having a section (15) extending out of the plane of the annular disk (6) by deformation and a section (16) extending parallel to the plane of the annular disk (6) with a free end (20).

5. The current transmission device (1) according to claim 4, characterized in that The free ends (20) of the lug-shaped sections (13, 14) are fixed to one another in a form-fitting manner at least in the circumferential direction.

6. The current transmission device (1) according to claim 5, characterized in that A dovetail-shaped connection (17) is arranged on the free end of the first lug-shaped section (13), which engages in a groove (18) corresponding thereto on the free end of the second lug-shaped section (14).

7. The current transmission device (1) according to any one of claims 3 to 6, characterized in that: The annular disk (6) has a circular opening (12) through which the rotor shaft (7) passes, and at which lug-shaped sections (13, 14) extending tangentially to the opening (12) and forming a guide (10) are formed.

8. The current transmission device (1) according to any one of the preceding claims, characterized in that The contact element (8) and / or the guide element (10) are formed identically.

9. An electric motor (3), comprising a current transmission device, characterized in that: The current transfer device is a current transfer device (1) according to any one of the preceding claims 1-8.

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