Current transmission device for rotor of electric machine

Abstract

The invention relates to a current transmission device (1) for a rotor (2) of an electric machine (3), comprising: a first annular disc (6) which is made of sheet metal, surrounds the circumference of a rotor shaft (7) of the rotor (2) and can be positioned non-rotatably relative to the rotor shaft, in which: electrical contact means (8) are positioned on the first annular disc (8), electrical contact means (8) which are spring-loaded in each case in the radial direction by means of a spring element (9) and which are guided in guide means (10) in a linearly displaceable manner in the direction of the rotor shaft (7), the contact means (8) thus being in electrically conductive contact with a circumferentially extending conductive track (11) of the rotor shaft (7); a receiving socket (12) is positioned on the first annular disc (6), which receiving socket extends outward from the first annular disc in the radial direction, and via which the current transmission device (1) can be coupled to an electrical conductor (13), the receiving socket (12) is integrally formed with the first annular disc (6) and is formed by a first tab-like portion (14) and a second tab-like portion (15) provided thereon, the second portion (15) being bent such that the first portion (14) rests thereon.

Description

Technical Field

[0001] The invention 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 comprising a first annular disk made of sheet metal, which circumferentially surrounds a rotor shaft of the rotor and can be positioned non-rotatably relative to the rotor shaft, wherein at least one electrical contact means is arranged on the first annular disk, which is subjected to a spring force in the radial direction by means of a spring element and is guided in a linearly displaceable manner in the direction of the rotor shaft in a guide means, the contact means thus making electrically conductive contact with at least one circumferentially extending conducting track of the rotor shaft, wherein at least one first receiving socket extending outwardly therefrom in the radial direction is arranged on the first annular disk, via which the current transmission device can be connected to an electrical conductor. Background Art

[0002] JP 2017-11 884 A, which is considered to be general, discloses a current transmission device as described above. A thin-walled annular disk carrying a number of contact devices distributed around the circumference completely surrounds the rotor shaft. A tab-shaped receiving socket extends radially away from the annular disk. The tab-shaped receiving socket can be used to connect the current transmission device to an electrical conductor. It can be seen that the receiving socket is a separate component connected to the annular disk (see Figure 3 ).

[0003] DE 10 2007 059 555 A1 discloses a modular current transmission device having two annular conductive plates, each of which is assigned a plurality of contact elements (brushes) (see Figure 1 ). A one-piece foot projects from each conductive plate to supply electrical energy thereto. Summary of the invention

[0004] The object of the present invention is to provide a production-optimized current transmission device for a rotor of an electric machine which ensures a high degree of operational reliability.

[0005] According to the invention, this object is achieved in that the first receiving socket is formed integrally with the first annular disk and is formed by a first tab-shaped portion and a second tab-shaped portion arranged on the first tab-shaped portion, the second portion being bent so that the first portion rests on the second portion, and wherein at least one of the two portions has a cylindrical ring protruding from it.

[0006] The receiving socket for the electrical contact is integrated in one piece into the base plate (annular disk) made of sheet metal. The receiving socket is thus formed by means of chipless forming. This reduces the number of components and the assembly effort, which has a positive effect on the manufacturing costs of the current transmission device. In addition, the one-piece design eliminates several components that could increase the contact resistance. In addition, due to the one-piece design with the annular disk, the risk of the receiving socket accidentally loosening is significantly reduced.

[0007] The receiving socket can be designed as a "classic" socket with an internal thread, so that, for example, a cable connector can be attached thereto using a screw. Alternatively, the screw can be connected to a washer, so that the cable connector is tightened by a nut. If two annular disks are mounted in a mirror-symmetrical manner, i.e. one on each pole, and a flat threaded surface is provided, this distance can be bridged using, for example, an additional sleeve.

[0008] The receiving socket extends radially out of the first annular disk. The advantage of this design is that it can be easily shaped, in particular easily bent, to form the receiving socket.

[0009] An essential component of the invention is that the receiving socket is formed by a first tab-shaped portion of a first annular disk and a second tab-shaped portion arranged on the first tab-shaped portion, wherein the second tab-shaped portion is bent so that the first tab-shaped portion rests on the second tab-shaped portion, which has proven to be particularly advantageous in terms of manufacturing technology.

[0010] In addition, the first tab-like part has a first cylindrical ring protruding therefrom and / or the second tab-like part has a cylindrical ring protruding therefrom. The advantageous effect of this design is due to the fact that it enables the fastening means to be guided through the receiving socket and also allows, for example, a defined axial distance to be defined between the tab-like parts when one part rests against the cylindrical ring of the other part.

[0011] According to an improved solution of the present invention, it can be provided that the first cylindrical ring has an internal thread and / or the second cylindrical ring has an internal thread, so that the screw can be screwed into the corresponding cylindrical ring.

[0012] Furthermore, the present invention is further developed such that the current transmission device has a second annular disk made of sheet metal, which circumferentially surrounds the rotor shaft of the rotor and is arranged on the first annular disk in a non-rotatable manner, wherein at least one electrical contact device is arranged on the second annular disk, which electrical contact device is subjected to a spring force in the radial direction by means of a spring element and is guided in a linearly displaceable manner in the guide device in the direction of the rotor shaft, the contact device thus making electrically conductive contact with at least one circumferentially extending conducting track of the rotor shaft, wherein at least one second receiving socket is arranged on the second annular disk, via which the current transmission device can be connected to a second electrical conductor, and wherein the second annular disk is structurally identical to the first annular disk.

[0013] The design of the two annular disks with the same shape (same construction) helps to further reduce the manufacturing costs. Therefore, from a manufacturing point of view, it is particularly preferred to make the first annular disk and / or the second annular disk from a metal sheet.

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

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

[0016] The electric machine is particularly intended for use in the drive train of a hybrid-drive or fully-electric motor vehicle. For the purposes of this application, a motor vehicle is a land vehicle that is moved by machine power without the constraints of railway tracks. The motor vehicle may, for example, be selected from the group of: a passenger car, a truck, a scooter, a light motor vehicle, a motorcycle, a bus / coach or a tractor.

[0017] The contact element can be, for example, an electric carbon brush. Particularly preferably, the contact element is a block-shaped solid body made of an electrically conductive material. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention is described in more detail below.

[0019] In the attached picture:

[0020] Figure 1 A schematic block diagram shows a motor vehicle having an electric drive train,

[0021] Figure 2 An electric machine having a first embodiment of a current transmission device is shown in a schematic axial section,

[0022] Figure 3 A schematic diagram of the contact device on the rotor is shown in a three-dimensional diagram,

[0023] Figure 4 An embodiment of a current transfer device is shown in two perspective views,

[0024] Figure 5 A second embodiment of the current transfer device is shown in a perspective view,

[0025] Figure 6 A second embodiment of a current transfer device is shown in schematic axial cross-section,

[0026] Figure 7 A sheet metal section of an annular disk of a current transfer device is shown in plan view. DETAILED DESCRIPTION

[0027] Figure 2 A current transmission device 1 is shown for a rotor 2 of an electric machine 3 designed as a radial flux machine, in particular an electric machine 3 in a drive train 4 of an electrically driven motor vehicle 5, as shown in FIG. Figure 1 The outlines are described by way of example.

[0028] As from Figure 2 and Figure 4 As can be clearly seen from the comparison of the figures, the current transmission device 1 comprises an annular disk 6 which circumferentially surrounds the rotor shaft 7 of the rotor 2 and is non-rotatably positioned relative to the rotor shaft 7. A plurality of electrical contact means 8 are arranged on the annular disk 6, each of which is subjected to a spring force in the radial direction by means of a spring element 9 and each of which is guided in a linearly displaceable manner in the direction of the rotor shaft 7 in the guide means 10, since the contact means 8 rests against the inner wall of the guide means 10 in a sliding manner.

[0029] As from Figure 3 It can be seen that the contact means 8 is in electrically conductive contact with at least one circumferential conductive track 11 of the rotor shaft 7. Figure 3 In the embodiment shown in FIG. , two half-shell-shaped conducting rails 11 form the commutator of the DC motor. Figure 2 As shown in FIG, for use in a separately excited synchronous motor, the conductive track 11 is then circumferentially closed, ie designed in an annular shape, or only one annular conductive track 11 is formed on the rotor 2. Figure 2 It will be appreciated that the current transfer device 1 can be used both in a DC motor and in a separately excited synchronous motor.

[0030] The guiding device 10 and Figure 4The annular disc 6 shown in the figure is formed integrally. The annular disc 6 is formed by a metal plate. A tab-shaped portion formed by deformation is arranged on the annular disc 6, which extends out of the plane of the annular disc 6 and thus forms a guide device 10 for the electrical contact device 8. The tab-shaped portions forming the guide device 10 each have a rectangular basic shape, and each of the tab-shaped portions has a portion extending out of the plane of the annular disc 6 by deformation and a portion with a free end extending parallel to the plane of the annular disc 6. The free ends of the tab-shaped portions are fixed to each other in a form-fitting manner at least in the circumferential direction. For this purpose, a dovetail web is provided at the free end of the first tab-shaped portion, which is engaged in a corresponding groove at the free end of the second tab-shaped portion.

[0031] The annular disk 6 also has a circular opening 18 through which the rotor shaft 7 passes and on which a tab-like portion is formed which extends tangentially to the opening 18 and forms the guide means 10. In the embodiment shown, the contact means 8 and the guide means 10 are substantially identical.

[0032] A first receiving socket 12 is arranged on the first annular disk 6, via which the current transfer device 1 can be coupled to a first electrical conductor 13. For this purpose, the electrical conductor 13 can have, for example, a cable connector or a cable eyelet, through which a fastening screw can pass to secure the electrical conductor 13 to the first receiving socket 12.

[0033] The first receiving socket 12 is formed integrally with the first annular disk 6 and extends in the radial direction out of the first annular disk 6. The receiving socket 12 is formed by a first tab-shaped portion 14 of the first annular disk 6 and a second tab-shaped portion 15 arranged on the first tab-shaped portion 14, wherein the second tab-shaped portion 15 is bent so that the first tab-shaped portion 14 rests on the second tab-shaped portion 15, which can be seen from Figure 4 can be clearly understood from the diagram in the figure. Figure 4 The upper image a of shows the upper side 19 of the annular disk 6 , and the lower image b shows the lower side 20 of the annular disk 6 .

[0034] The first tab-like portion 14 has a first cylindrical ring 16 which protrudes from it in the axial direction and has an internal thread so that a fastening means 17 designed, for example, as a screw can be screwed into the cylindrical ring 16 and the electrical conductor 13 can thus be fixed to the receiving socket 12 .

[0035] Figure 5 and Figure 6A further embodiment of a current transmission device 1 is shown, in which the current transmission device 1 has a second annular disk 26, which at least partially circumferentially surrounds the rotor shaft 7 of the rotor 2 and is arranged in a non-rotatable manner on the first annular disk 6. Also arranged on the second annular disk 26 is at least one electrical contact means 28, which is subjected to a spring force in the radial direction by means of a spring element 29 and is guided in a linearly displaceable manner in a guide means 30 in the direction of the rotor shaft 7. The contact means 28 is thus in electrically conductive contact with at least one circumferential conducting track 31 of the rotor shaft 7. Also arranged on the second annular disk 26 is a second receiving socket 32, via which the current transmission device 1 can be coupled to a second electrical conductor 33.

[0036] For this purpose, as in Figures 2 to 4 In the embodiment of the present invention, the collar-shaped part 14 is radially drawn out of the annular disc 6, 26 and is provided, for example, with a deep-drawn cylindrical ring 36 with an internal thread. In order to use the same annular disc 6, 26 for both electrodes, the tab-shaped part 15, 35 is additionally bent, which provides a second rear receiving surface. The tab-shaped part 14, 34 and the tab-shaped part 15, 35 each have a socket opening 21, 41 or a socket opening 22, 42 for passing a fastening means 17, such as a mounting screw. An insulating disc 23 is axially arranged between the annular discs 6, 26, which provides electrical insulation of the two annular discs 6, 26 from each other.

[0037] The first annular disk 6 and the second annular disk 26 are formed from a metal sheet having substantially the same metal sheet sections. Figure 7 2 shows sheet metal sections of annular disks 6, 26. Thus, the first annular disk 6 and the second annular disk 26 are made essentially of the same parts.

[0038] Figure 7 Briefly describes how to make Figures 2 to 6 A known current transmission device 1 is provided.

[0039] Firstly, a first annular disk 6 is provided, which can at least partially circumferentially surround the rotor shaft 7 of the rotor 2, wherein the annular disk 6 is arranged with a first tab-like portion 14 and a second tab-like portion 15 arranged on the first tab-like portion 14. Figure 7 The sheet metal cutting piece is shown in FIG.

[0040] from Figure 7Starting from the sheet metal cut piece shown in , the second tab-like portion 15 is then bent by approximately 180° so that the first tab-like portion 14 rests against the second tab-like portion 15 and thus forms a first receiving socket 12 via which the current transfer device 1 can be coupled to the first electrical conductor 13. For example, in Figure 4 The production status can be seen in .

[0041] For example, to provide internal threads in the receiving socket 12, a cylindrical ring 16, 36 may be formed in the metal sheet cut before bending by a forming step, the cylindrical ring extending out of the plane of the tab-like portion 14, 34. Then, internal threads are cut in the inner lateral surface of the corresponding cylindrical ring 16, 36.

[0042] Reference numerals list

[0043] 1 Current transmission device

[0044] 2 Rotors

[0045] 3 Motor

[0046] 4 Drivetrain

[0047] 5 Motor vehicles

[0048] 6 First annular disc

[0049] 7 Rotor shaft

[0050] 8 Contact devices

[0051] 9 Spring element

[0052] 10 Guidance Devices

[0053] 11 Conducting track

[0054] 12 Receiving socket

[0055] 13 Conductor

[0056] 14 Part 1

[0057] 15 Part 2

[0058] 16 First cylindrical ring

[0059] 17 Fastening devices

[0060] 18 Opening

[0061] 19 upper surface

[0062] 20 lower face

[0063] 21 Socket opening

[0064] 22 Socket opening

[0065] 23 Insulation disc

[0066] 26 second annular disc

[0067] 28 Contact devices

[0068] 29 Spring element

[0069] 30 Guidance Device

[0070] 31 Conducting Track

[0071] 32 receiving socket

[0072] 33 Conductor

[0073] 34 Part 1

[0074] 35 Part 2

[0075] 36 First cylindrical ring

[0076] 41 First socket opening

[0077] 42 Second socket opening

Claims

1. A current transmission device (1) for a rotor (2) of an electric machine (3), in particular in a drive train (4) of an electrically driven motor vehicle (5), the current transmission device comprising a first annular disk (6) made of sheet metal, which circumferentially surrounds a rotor shaft (7) of the rotor (2) and can be non-rotatably positioned relative to the rotor shaft, at least one electrical contact device (8) being arranged on the first annular disk (6), the electrical contact device being subjected to a spring force in the radial direction by means of a spring element (9) and being guided in a linearly displaceable manner in a guide device (10) in the direction of the rotor shaft (7), the contact device (8) thus being in electrically conductive contact with at least one circumferentially extending conducting track (11) of the rotor shaft (7), at least one first receiving socket (12) being arranged on the first annular disk (6) extending from the first annular disk in the radial direction, the current transmission device (1) being connectable to a first electrical conductor (13) via the first receiving socket, characterized in that The first receiving socket (12) is formed integrally with the first annular disk (6) and is formed by a first tab-like portion (14) and a second tab-like portion (15) arranged on the first tab-like portion, the second portion (15) being bent so that the first portion (14) rests on the second portion, and wherein at least one of the two portions (14, 15) has a cylindrical ring (16) protruding from the at least one portion.

2. The current transmission device according to claim 1, characterized in that: In the case where there is only one cylindrical ring (16) on one of the two parts (14, 15), the cylindrical ring (16) has an internal thread, and wherein in the case where there is one cylindrical ring (16) on each of the two parts (14, 15), at least one of the cylindrical rings has an internal thread.

3. The current transmission device according to claim 1, characterized in that: The current transmission device (1) comprises a second annular disk (26) made of sheet metal, which circumferentially surrounds the rotor shaft (7) of the rotor (2) and is arranged on the first annular disk (6) in a non-rotatable manner, wherein at least one electrical contact means (28) is arranged on the second annular disk (26), which is subjected to a spring force in the radial direction by means of a spring element (29) and is guided in a linearly displaceable manner in a guide means (30) in the direction of the rotor shaft (7), the contact means (28) thus being in electrically conductive contact with at least one circumferentially extending conducting track (31) of the rotor shaft (7), wherein a second receiving socket (32) extending from the second annular disk in the radial direction is arranged on the second annular disk (26), via which the current transmission device (1) can be connected to a second electrical conductor (33), and wherein the second annular disk (26) is structurally identical to the first annular disk (6).

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