rolling bearings

Abstract

Rolling bearing comprising an outer ring (3), an inner ring (4), rolling elements (7) received between the outer ring (3) and the inner ring (4), an insulating layer (9) forming the inner circumference of the rolling bearing (1), and a current supply device (12) provided on an axial side of the rolling bearing (1), which does not rotate in the mounting position and comprises an input terminal (14) for a current supply, wherein the current supply device (12) is contacted with a current transmission device (13) which rotates in the mounting position and on which an output terminal (15) is provided, wherein the current supply device (12) comprises a guide ring (26) received in a housing (16) which has an input terminal (14), and the current transmission device (13) comprises the inner ring (4), wherein the inner ring (4) is connected to the output terminal (15) and wherein the guide ring (26) is in contact with the inner ring (4).

Description

[0001] The invention relates to a rolling bearing.

[0002] Rolling bearings are used wherever two components need to be mounted so they can rotate relative to each other. One example is the mounting of the rotor of an electric machine, such as those found in electric axles in the automotive sector. These rolling bearings, which are usually ball bearings, can be designed to be electrically insulating or current-dissipating in such applications, as they are used in current-carrying or current-generating areas. In addition to mounting the rotor, if the electric machine is designed as a separately excited machine, a controlled current supply to the electrical windings on the rotor is required. For this purpose, a special, separate rotary feedthrough is typically provided, connecting stationary terminals on the housing to the rotating rotor shaft. This necessitates separate slip ring elements on the rotor shaft.From DE 691 08 651 T2 a rolling bearing with rotating electrical contacts is also known, which are designed to transmit electrical current between two mechanical parts, one of which is rotatable relative to the other.

[0003] The invention is based on the problem of providing an improved rolling bearing.

[0004] To solve the problem, a rolling bearing is provided according to the invention, comprising an outer ring, an inner ring, rolling elements received between the outer ring and the inner ring, an insulating layer forming the inner circumference of the rolling bearing, and a current supply device provided on an axial side of the rolling bearing, which does not rotate in the mounting position and comprises an input connection for a current supply, wherein the current supply device is contacted with a current transmission device which rotates in the mounting position and on which an output connection is provided, wherein the current supply device has a guide ring received in a housing which has an input connection and the current transmission device comprises the inner ring, wherein the inner ring is connected to the output connection and wherein the guide ring is in contact with the inner ring.

[0005] The rolling bearing according to the invention is characterized, firstly, by the typical bearing components in the form of an outer ring, an inner ring, and rolling elements mounted between them, which roll on corresponding raceways. While the outer ring is fixedly mounted in a corresponding bearing seat on a housing, the inner ring sits on the rotor shaft and thus rotates with it. Additionally, the rolling bearing includes a device that allows current to be directed to the rotor via the rolling bearing itself in order to energize the windings there. For this purpose, the rolling bearing according to the invention includes a current supply device that does not rotate in the mounted position and has an input terminal to which a power source can be connected. Furthermore, a current distribution device is provided that is connected to the current supply device.While the current supply device is stationary, i.e., it does not rotate, the current distribution device is connected to the rotating part of the rolling bearing and thus rotates with the rotor. This current distribution device has an output terminal that can be connected to a downstream winding on the rotor side. Therefore, a corresponding operating current can be supplied from an external source to the winding to be energized via the current supply device and the current distribution device, with this current supply occurring solely through the rolling bearing.

[0006] According to the invention, the current supply device has a conductive ring, e.g., a simple sheet metal ring, which has an input terminal. Likewise, the current distribution device has an output terminal. This means that the rolling bearing enables integrated single-pole current conduction. To achieve this, the current supply device is designed with a conductive ring that is separately contacted with the current distribution device. The current distribution device, in turn, comprises the inner ring itself, i.e., the inner ring of the rolling bearing, which primarily serves the bearing purpose, also functions as a current conductor. Furthermore, the current distribution device includes an insulating layer that forms the inner circumference of the rolling bearing and insulates the rolling bearing itself from the rotor shaft. The inner ring is connected to an output terminal.Therefore, a guide path is implemented, namely via the input port, the guide disk, the inner ring and the output port.

[0007] The rolling bearing according to the invention is thus a multifunctional bearing designed as a compact unit. On the one hand, it provides the bearing function by which the rotor shaft can be rotatably supported in the housing, and on the other hand, it offers a current-carrying function, as it is equipped with a single-pole, i.e., simple, current-carrying function. With the installation of the rolling bearing according to the invention, both functionalities are available, so that no rotary feedthrough or any sliding contacts on the rotor shaft are required. To implement the second pole for winding current supply, another bearing according to the invention is used in the installation position to support the rotor shaft; alternatively, a conventional slip ring can also be used.

[0008] The guide ring is advantageously contacted with the inner ring via a sliding contact. In the rolling bearing according to the invention, the contact plane is implemented as a sliding contact plane, which is, however, integrated into the rolling bearing. Preferably, a sliding contact disc is provided as part of the current supply device to implement the sliding contact, with the guide ring bearing axially against the sliding contact disc. Thus, a package consisting of the guide ring and the sliding contact disc is provided, which is part of the current supply device. The sliding contact disc preferably has a radial sliding contact section via which it is contacted with a radial contact section of the inner ring. This radial sliding contact enables simple assembly of the current supply device, since the radial sliding contact to the inner ring is automatically formed when the corresponding sliding contact disc is arranged axially.

[0009] The sliding contact disc is preferably made of carbon, sometimes also called a carbon disc, which is a disc consisting of carbon fibers or a carbon fiber mesh, possibly impregnated with plastic. This sliding contact disc allows for a correspondingly high current-carrying sliding contact that is extremely wear-resistant. However, the sliding contact disc can also be made of other conductive materials, such as copper.

[0010] To accommodate the corresponding components of the current supply device that serve the current conductor, the current supply device preferably has an annular housing with an annular receiving chamber in which the guide ring and, if applicable, the sliding contact disc are received. This annular housing encapsulates and protects the ring or disc assembly. The housing can also simultaneously provide the possibility of axial contacting the ring or disc assembly, i.e., that the corresponding components are axially clamped within the housing.

[0011] The housing itself can advantageously include an axially end connecting disc, via which the current supply device is connected to the outer ring, and another axially end angled disc, which is connected to the connecting disc via a cylindrical connecting section, so that the receiving space is formed between the connecting disc and the angled disc. The housing is thus designed in only two parts, comprising the connecting disc and the angled disc. The connecting disc links the housing to the outer ring, so that the housing is firmly connected to this positionally fixed part of the bearing section of the rolling bearing. The angled disc completes the housing.It is connected to the connecting disc via a cylindrical connecting section on the angled disc. This section, for example, has several openings in the connecting disc with corresponding fingers that are crimped behind the connecting disc. The annular receiving space is defined between the connecting disc and the angled disc, in which the guide ring and, if applicable, the sliding contact disc are located. The housing design is therefore very simple, as is its assembly and connection to the outer ring.

[0012] The receiving space preferably contains insulating discs that insulate the guide ring and the sliding contact disc from the connecting disc and the angled disc. These insulating discs thus provide axial insulation from the connecting disc and the angled disc if they are made of metal. This results in a multi-part ring or disc assembly, for example, consisting of two end insulating discs between which the guide ring and the sliding contact disc are mounted. The insulating discs themselves are, of course, made of a suitable electrically insulating material, in particular a plastic.

[0013] The insulating layer provides electrical insulation between the rolling bearing or the current-conducting inner ring and the rotor shaft. It is made of a suitable insulating material, usually a plastic.

[0014] As described, the inner ring, as part of the current conduction system, directly participates in the current flow. To ensure the rolling bearing is electrically insulated from the housing, the outer ring can have an insulating layer forming its outer circumference. This means that a corresponding insulating layer made of a suitable insulating material, i.e., plastic, is also provided on the outer ring, electrically insulating it from the bearing seat.

[0015] As described, the inner ring is contacted with a corresponding output terminal. To simplify this, a contact ring with the output terminal can be arranged on the inner ring. Both the input and output terminals can be designed, for example, as protruding tabs or similar features.

[0016] The invention is explained below with reference to exemplary embodiments and the drawing. The drawing is a schematic representation.

[0017] The figure shows a schematic representation of a rolling bearing according to the invention in a sectional view.

[0018] The figure shows a schematic representation of a rolling bearing according to the invention 1.

[0019] The rolling bearing 1 according to the invention comprises, firstly, the actual bearing section 2, which is formed by an outer ring 3, an inner ring 4, and, between them, rolling elements 7 in the form of balls that roll on raceways 5, 6. An insulating layer 8, e.g., made of plastic, is applied to the outer circumference and the end faces of the outer ring 3, by means of which the rolling bearing 1 is insulated from a bearing seat of a housing in which the rolling bearing 1 or the outer ring 3 is received. The inner ring 4 is also equipped with an insulating layer 9, by means of which it is electrically insulated from a rotor shaft 10 (shown here only symbolically), on which it sits.

[0020] The rolling bearing 1 further comprises a current conducting device 11, comprising a current supply device 12 and a current distribution device 13. The current supply device 12 is equipped with an input terminal 14. The current distribution device 13 is provided with an output terminal 15. While the input terminal 14 is fixed in position, since the current supply device 12 as a whole is fixed in position, the output terminal 15 is rotatable, as it is provided on the rotating part of the rolling bearing 1 and is to be connected to windings of the rotor (not shown).

[0021] The power supply device 12 comprises a housing 16, including an axially terminal connecting disc 17, which is connected to the outer ring 3 via a mounting section 18. The outer ring 3 has an annular groove 19 into which the mounting section 18 engages. Furthermore, the housing 16 has an angled disc 20, which displays a cylindrical connecting section 21. This connecting section has corresponding retaining fingers 22 that extend through axial openings in the connecting disc 17, the retaining fingers 22 being bent behind the connecting disc 17. A radial recess 23 is provided in the cylindrical connecting section 21, through which a contact, on which the input terminal 14 is arranged, is guided. This will be discussed in more detail below.

[0022] Inside the housing, a receiving chamber 25 is formed in which a ring or disk assembly is arranged. This assembly includes a guide ring 26, which is designed as a simple sheet metal ring. The guide ring 26 extends through the recesses 23 with a contact section 27, and the input terminal 14 is arranged on the contact section 27.

[0023] A sliding contact disc 28, preferably a carbon fiber disc or carbon disc, is axially adjacent to the guide ring 26 and has radial sliding contacts 29 formed on its inner circumference. The sliding contact disc 28 is in electrical contact with the guide ring 26, and the current supplied via the input terminal 14 is transmitted via it to the rotating part of the current conduction device 11 or the current distribution device 13.

[0024] Furthermore, two insulating washers 30, 31 are provided, by which the guide ring 26 and the sliding contact disc 28 are insulated from the connecting disc 17 and the angle disc 20, respectively. This results in a corresponding ring or disc assembly, which is axially clamped inside the receiving space 25, the axial clamping being provided by the corresponding connection of the angle disc 20 to the connecting disc 17.

[0025] The current conduction device 13 comprises the inner ring 4, which has a radial contact section 32 against which the radial sliding contact section 29 of the sliding contact disc 28 rests. On the other side of the inner ring 4, a contact ring 33 is arranged, on which the output terminal 15 is arranged.

[0026] The rolling bearing according to the invention is therefore equipped with both a bearing section 2 serving as a rotary bearing and a single-pole current-conducting device 11 serving as a current-conducting device. This current-conducting device 11 has an insulated conduction path formed via the input terminal 14, the guide ring 26, the sliding contact disc 28, the inner ring 4, the contact ring 33, and the output terminal 15. Since the current-input device 12 is positionally fixed, as it is connected to the positionally fixed outer ring 3 via its housing 16, and since the current-conducting device 13 is coupled to the rotating part of the rolling bearing 1, i.e., the inner ring 4, but an electrical sliding contact exists between the two, the current can be supplied directly to the rotor shaft or the windings provided therein via the rolling bearing 1 itself. Reference symbol list 1 rolling bearing 2 Storage section 3 Outer ring 4 inner ring 5 Career 6 Career 7 rolling elements 8 layers of insulation 9 Insulation layer 10 Rotor shaft 11 Current conduction device 12 Power supply device 13 Power transmission device 14 Input connection 15 Output port 16 cases 17 Connecting washer 18 Fastening section 19 Ring groove 20 Angle washer 21 Connecting section 22 holding fingers 23 Exclusion 25 Recording room 26 guide ring 27 Contact section 28 Grinding contact disc 29 Sliding contact 30 insulating discs 31 insulating washer 32 Contact section 33 Contact ring

Claims

Rolling bearing comprising an outer ring (3), an inner ring (4), rolling elements (7) received between the outer ring (3) and the inner ring (4), an insulating layer (9) forming the inner circumference of the rolling bearing (1), and a current supply device (12) provided on an axial side of the rolling bearing (1), which does not rotate in the mounting position and comprises an input terminal (14) for a current supply, wherein the current supply device (12) is contacted with a current transmission device (13) which rotates in the mounting position and on which an output terminal (15) is provided, wherein the current supply device (12) comprises a guide ring (26) received in a housing (16) which has an input terminal (14), and the current transmission device (13) comprises the inner ring (4), wherein the inner ring (4) is connected to the output terminal (15) and wherein the guide ring (26) is in contact with the inner ring (4). Rolling bearing according to claim 1, characterized in that the guide ring (26) is contacted with the inner ring (4) via a sliding contact. Rolling bearing according to claim 2, characterized in that the current supply device (12) has a sliding contact disc (28), wherein the guide ring (26) rests axially against the sliding contact disc (28). Rolling bearing according to claim 3, characterized in that the grinding contact disc (28) is contacted via a radial grinding contact section (29) on a radial contact section (32) of the inner ring (4). Rolling bearing according to one of the preceding claims, characterized in that the housing (16) is annular and has an annular receiving space (25) in which the guide ring (26) and optionally the sliding contact disc (28) are received. Rolling bearing according to claim 5, characterized in that the housing (16) is formed via an axially terminal connecting disk (17) through which the current supply device (12) is connected to the outer ring (3), and a further axially terminal angle disk (20) which is connected to the connecting disk (17) via a cylindrical connecting section (21) so that the receiving space (25) is formed between the connecting disk (17) and the angle disk (20). Rolling bearing according to claim 6, characterized in that insulating discs (30, 31) are received in the receiving space (25), by means of which the guide ring (26) and the sliding contact disc are insulated from the connecting disc (17) and the angle disc (20). Rolling bearing according to one of the preceding claims, characterized in that the outer ring (3) has an insulating layer (8) forming the outer circumference. Rolling bearing according to one of the preceding claims, characterized in that a contact ring (33) on the inner ring (4), on which one output connection (156) is provided, is arranged.

Images