Rolling element bearing

Abstract

A rolling element bearing, comprising an outer ring (3), an inner ring (4), rolling elements (7) accommodated between the outer ring (3) and the inner ring (4), an insulation layer (9) forming the inner circumference of the rolling element bearing (1), and a current supply device (12) which is provided on an axial side of the rolling element bearing (1) and which does not rotate in the assembly position, said current supply device (12) comprising an input connection (14) for a current supply; wherein the current supply device (12) is in contact with a current relay device (13) which does rotate in the assembly position, an outlet connection (15) being provided on said current relay device (13); wherein the current supply device (12) has a conductive ring (18) having the inlet connection (14), and the current relay device (13) comprises a conductor (23), with said outlet connection (15), said conductor being embedded in the insulation layer (9); wherein the conductive ring (18) is in contact with the conductor (23).

Description

[0001] rolling bearings

[0002] The invention relates to a rolling bearing.

[0003] 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.

[0004] The invention is based on the problem of providing an improved rolling bearing.

[0005] 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 which has the input connection and the current transmission device comprises a conductor embedded in the insulating layer with the output connection, wherein the guide ring is in contact with the conductor.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 guide ring, e.g., a simple sheet metal ring, which has an input terminal. Likewise, the current transmission device has an output terminal. This means that the rolling bearing enables integrated single-pole current transmission. To achieve this, the current supply device is designed with a guide ring that is contacted with the current transmission device. The current transmission device, in turn, comprises a conductor embedded in the insulating layer that electrically insulates the rolling bearing from the rotor shaft, and this conductor has the output terminal or is contacted with one. Consequently, a conduction path is realized that is formed via the input terminal, the guide ring, the embedded conductor, and the output terminal.

[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 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 conductor 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 conductor. This radial sliding contact enables simple assembly of the current supply device, since the radial sliding contact to the conductor is automatically formed when the 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 contact the sliding contact disc with the conductor, the conductor is advantageously connected to a contact ring embedded in the insulating layer, with the sliding contact disc being in contact with the contact ring. The contact ring thus forms a circumferential contact section to which the conductor is locally connected, resulting in a permanent sliding contact. Preferably, the sliding contact disc is contacted to the contact ring via a radial sliding contact section.

[0011] For mounting and securing the current supply device on the rolling bearing section, the current supply device comprises an annular retaining disc. This disc is fixed to the guide ring by several retaining fingers that extend through openings in the guide ring and are bent behind them. The sliding contact disc is located between the retaining disc and the guide ring, and the guide ring is fixed to the outer ring. The assembly of guide ring and sliding contact disc can be axially clamped via the annular retaining disc. For this purpose, the retaining disc is firmly connected to the guide ring by means of several axially projecting retaining fingers that extend through openings in the guide ring and are bent behind them. In addition to conducting the current, the guide ring itself also serves to directly attach the current supply device to the outer ring and thus to the rolling bearing section, resulting in a very compact design.The guide ring is insulated from the outer ring via the insulation layer.

[0012] To secure the guide ring to the outer ring, the guide ring can be provided with an annular mounting section that engages in an annular groove of the outer ring. This allows for a simple, positive-locking and force-fit attachment of the power supply device to the rolling bearing section. The mounting section can, for example, be snapped or fixed into the annular groove.

[0013] As described, the conductor embedded in the insulating layer provided on the inner circumference of the inner ring is a central element. The insulating layer provides electrical insulation of the rolling bearing from the rotor shaft. It is made of a suitable insulating material, usually a plastic. According to the invention, the conductor is embedded in this insulating layer in such a way that it is also electrically insulated relative to the inner ring, thus preventing any contact between the metallic conductor and the inner ring. The conductor itself is advantageously a simple metallic conductor, particularly made of steel or copper.

[0014] As described, the conductor is connected to the output terminal. To simplify this, a protruding terminal section can be provided at the end of the conductor, where the electrical contact of the windings takes place. Both the input and output terminals are designed, for example, as protruding lugs or similar features.

[0015] As described, the rolling bearing is insulated on its inner circumference towards the rotor shaft via an insulating layer. To ensure that the rolling bearing is also electrically insulated towards 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.

[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 is provided on the outer circumference and the end faces of the outer ring 3, by means of which the rolling bearing 1 is arranged in a bearing seat of a housing in which the rolling bearing 1, or rather the outer ring 3, is received, and is electrically insulated from the housing. The inner ring 4 is also equipped with an insulating layer 9 on its inner circumference, 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. Likewise, 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 located 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 has a retaining disc 16 with axially extending retaining fingers 17. These retaining fingers 17 extend through openings provided in a guide ring 18. They are bent behind the guide ring 18 so that the retaining disc is fixed to the guide ring. The guide ring 18, in turn, is connected to the outer ring 3 via an annularly circumferential mounting section 19. For this purpose, the outer ring 3 has an annular groove 20 into which the mounting section 19 engages. The guide ring 18 is insulated from the outer ring 3 by the insulating layer 8. The input terminal 14 is provided on the guide ring 18. Furthermore, a sliding contact disc 21 is provided, which bears directly against the guide ring 18 and is clamped between the guide ring 18 and the retaining disc 16.

[0022] The sliding contact disc 21 is preferably a carbon fiber disc or carbon disc. It has a radial sliding contact section 22 formed on its inner circumference. As described, the sliding contact disc 21 is in electrical contact with the guide ring 18, and the current supplied via the input terminal 14 is transmitted via it to the rotating part of the current conducting device 11 or the current transfer device 13. The current transfer device 13 comprises a conductor 23 embedded in the insulation layer 9, which has the output terminal 15. The conductor 23 is electrically insulated via the insulation layer 9 from both the inner ring 4 and the rotor shaft 10. At the other end of the conductor 23, also embedded in the insulation layer 9, a contact ring 24 is provided. The contact ring 24 is exposed so that the sliding contact 22 can bear against it.

[0023] The rolling bearing according to the invention is therefore equipped with both a bearing section 2 serving as a rotary bearing and a 1-pole section serving as a current conductor.

[0024] The bearing 11 is equipped with a current-conducting device. This current-conducting device 11 has an insulated conductor path formed via the input terminal 14, the guide ring 18, the sliding contact disc 21, the contact ring 24, the conductor 23, and the output terminal 15. Since the current-conducting device 12 is fixed in position, and since the current-conducting device 13 is coupled to the rotating part of the rolling bearing 1, but an electrical sliding contact exists between the two, the current can therefore be supplied directly to the rotor shaft or the windings provided therein via the rolling bearing 1 itself.

[0025] List of reference signs

[0026] rolling bearings

[0027] Storage section

[0028] outer ring

[0029] inner ring

[0030] career

[0031] career

[0032] rolling elements

[0033] Insulation layer

[0034] Insulation layer

[0035] Rotor shaft

[0036] Current conduction device

[0037] Power supply unit

[0038] Power relay device

[0039] Input port

[0040] Output connection

[0041] retaining disc

[0042] Holding finger

[0043] Guide ring

[0044] Fastening section

[0045] Ring groove

[0046] Grinding contact disc

[0047] Sliding contact section

[0048] Director

[0049] Contact ring

Claims

Patent claims 1. 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 transfer device (13) which rotates in the mounting position and on which an output terminal (15) is provided, wherein the current supply device (12) has a guide ring (18) having the input terminal (14) and the current transfer device (13) comprises a conductor (23) embedded in the insulating layer (9) with the output terminal (15), wherein the guide ring (18) is in contact with the conductor (23).

2. Rolling bearing according to claim 1, characterized in that the guide ring (18) is contacted with the conductor (23) via a sliding contact.

3. Rolling bearing according to claim 2, characterized in that the current supply device (12) has a sliding contact disc (21 ), wherein the guide ring (18) rests axially against the sliding contact disc (21 ).

4. Rolling bearing according to claim 3, characterized in that the grinding contact disc (21 ) is a carbon disc.

5. Rolling bearing according to claim 3 or 4, characterized in that the conductor (23) is connected to a contact ring (24) embedded in the insulating layer (9), wherein the sliding contact disc (21) is in contact with the contact ring (24).

6. Rolling bearing according to one of claims 3 to 5, characterized in that the grinding contact disc (21 ) is contacted via a radial grinding contact section (22) on the contact ring (24).

7. Rolling bearing according to one of the preceding claims, characterized in that the current supply device (12) comprises an annular retaining disc (16) which is fixed to the guide ring (18) via several retaining fingers (17) that extend through the openings in the guide ring (18) and are bent behind them, wherein the sliding contact disc (21) is received between the retaining disc (16) and the guide ring (18), and wherein the guide ring (18) is fixed to the outer ring (3).

8. Rolling bearing according to claim 7, characterized in that the guide ring (18) has an annular fastening section (19) which engages in an annular groove (20) provided on the outer ring (3).

9. 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.

Images