Support device for a rotor with roving winding

Description

[0001] The invention relates to a salient-pole rotor for an electrical machine. The salient-pole rotor has a rotor core, which has a rotor yoke and salient poles arranged circumferentially on the rotor yoke. Two radially opposite salient poles form a salient-pole pair. The salient poles each have a rotor tooth and a pole shoe. Furthermore, the salient-pole rotor comprises magnetic-field-generating windings wound around the rotor teeth of the salient poles and forming winding heads on opposite end faces of the rotor core, and a support device for supporting the winding heads. The invention also relates to an electrical machine.

[0002] In this case, the focus is on electrical machines that can be used, for example, as drive motors for electrified motor vehicles, i.e., electric or hybrid vehicles. Such electrical machines typically have a stationary stator with energizable stator windings and a rotor mounted so as to be rotatable relative to the stator. In the case of a separately excited machine, the rotor also has energizable rotor windings. In the case of a salient-pole rotor, these windings can be wound around salient poles or rotor poles of a rotor core. The windings are guided, for example, to form winding overhangs over star disks arranged on axially opposite end faces of the laminated core. For reasons of stability, the winding overhangs are each encased in an end cap or support ring.The support rings can be mechanically connected to the respective star disk, for example, via a bayonet lock. The star disk-support ring design supports the winding heads at the outermost area of ​​the salient pole rotor, where the greatest centrifugal forces act. This can lead to insufficient support of the winding heads at high speeds, particularly in the area of ​​the connecting wires from the winding heads to the current generator. US 2014 / 091670 A1 discloses a support device for a salient pole rotor that protects against centrifugal forces.

[0003] It is an object of the present invention to provide a support device for a salient pole rotor of an electrical machine with a particularly high support effect.

[0004] This object is achieved according to the invention by a salient-pole rotor and an electric machine having the features according to the respective independent patent claims. Advantageous embodiments of the invention are the subject of the dependent patent claims, the description, and the figures.

[0005] A salient-pole rotor according to the invention for an electrical machine comprises a rotor core having a rotor yoke and salient poles arranged circumferentially distributed on the rotor yoke, wherein two radially opposite salient poles form a salient-pole pair, and wherein the salient poles each have a rotor tooth and a pole shoe. Furthermore, the salient-pole rotor has magnetic-field-generating windings wound around the rotor teeth of the salient poles and forming winding heads on opposite end faces of the rotor core, and a support device for supporting the winding heads. The support device has a tensioning and deflection device and a roving winding with at least one roving. The roving forms a plurality of windings offset in the circumferential direction and spanning the windings of a salient-pole pair.For this purpose, the roving has axial first roving sections and end-face second roving sections, wherein the second roving sections are guided over the winding heads by means of the tensioning and deflecting device to form a winding between radially opposite salient poles and are deflected along the circumferential direction to form a winding transition between two windings when guided over the winding heads.

[0006] The invention also includes an electric machine with a stator and a salient-pole rotor according to the invention that is rotatably mounted relative to the stator. The electric machine is designed, in particular, as a current-excited internal rotor synchronous machine (SSM). The electric machine is, in particular, a traction motor of an electrified motor vehicle.

[0007] The rotor core of the salient-pole rotor is designed, for example, as a laminated core made of axially stacked and interconnected electrical steel laminations. The rotor core has the rotor yoke, for example, a ring-shaped one, through which a rotor shaft can be passed and connected in a rotationally fixed manner to the rotor core. The rotor teeth project radially from the rotor yoke and are arranged spaced from one another in the circumferential direction. The circular-segment-shaped pole pieces are arranged on the rotor teeth. Portions of the pole pieces project along the circumferential direction, so that winding conductors of the windings, which are wound around the rotor teeth, are arranged radially between the pole pieces and the rotor yoke and are held on the rotor teeth by the pole pieces when the salient-pole rotor rotates.

[0008] A star disk can also be arranged on each of the axially opposite end faces of the rotor core, which serves to guide the winding conductors over the end faces of the rotor core. The geometric shape of the star disks corresponds to the salient pole design of the rotor core. The winding conductor sections guided over the end faces form the winding heads. These can be held on the star disks by axially protruding projections of the star disks as the rotor rotates, thus supporting them against the centrifugal forces acting during rotation. To improve the supporting effect of the star disks against the centrifugal forces, the salient pole rotor also features the support device.

[0009] The support device has a roving. A roving is a bundle or strand of parallel filaments (continuous fibers). The roving is designed in particular as a plastic fiber bundle or glass fiber bundle. This roving or fiber bundle is wound in pairs in several turns around the energizable windings such that two opposite salient poles are mechanically connected or braced under tension. The windings of each salient pole pair are surrounded by at least one turn. The roving winding or fiber bundle winding preferably has at least two turns for each salient pole pair. At least one turn is arranged in each case on the circumferentially opposite pole shoe areas of the pole shoes that protrude from the respective rotor teeth.The turns extend in the axial direction along the windings and in the radial direction over the winding heads and are arranged offset from one another in the circumferential direction, with two turns each being connected via a turn transition. The tensioning and deflecting device is provided for the circumferentially offset arrangement of the turns and for guiding the second, end-side roving sections past the rotor shaft of the salient pole rotor. The tensioning and deflecting device has, in particular, two tensioning and deflecting rollers, which are arranged in a rotationally fixed manner on the axially opposite end faces of the rotor core. For example, the tensioning and deflecting rollers are connected in a rotationally fixed manner on both end faces to the rotor shaft which passes through the rotor core. The tensioning and deflecting rollers have, in particular, a plurality of guide grooves arranged axially one above the other for deflecting and guiding the second roving sections past the rotor shaft of the salient pole rotor.

[0010] To assemble the support device on the salient pole rotor, in particular, a roving start is wound several times around the first tensioning and deflecting roller to secure the roving by forming a roving train. Starting from the first tensioning and deflecting roller, the roving is guided over the winding head of the first end face to a first salient pole of a first salient pole pair and is guided axially along the winding of this salient pole from the first end face to the second end face. There, the roving is guided by means of the second tensioning and deflecting roller over the winding head of the second end face, past the rotor shaft, to a radially opposite second salient pole of the first salient pole pair. From there, the roving is guided axially along the winding of the second salient pole back to the first end face, where it is guided over the winding head of the first end face by means of the first tensioning and deflecting roller, completing the first turn.The roving is deflected along the circumferential direction by the first tensioning and deflection roller, so that a second turn is initiated, offset from the first turn. The roving is deflected along the circumferential direction so that the second turn either begins again at the first salient pole, thus forming another turn for the first salient pole pair, or the second turn begins at a salient pole of a second salient pole pair, thus forming a turn for the second salient pole pair. Sufficient turns are created so that each salient pole pair is wrapped with at least one turn.

[0011] Such a support device, formed by a tensioning and deflection device and a roving winding, has a high supporting effect against centrifugal forces, especially at high speeds.

[0012] Particularly preferably, axially extending gaps are formed between the windings and the pole shoes of the salient poles, in which the first, axial roving sections are arranged. The gaps are open and thus accessible only via pole gaps formed between two salient poles. The roving is first deflected along the circumferential direction in order to be able to arrange it in the pole gap and to be able to insert or thread it tangentially into the gap. In particular, the star disks have insertion aids for inserting the first roving sections into the gaps. For example, the insertion aids are designed as pins of the star disks that project axially from the winding heads and between which pins the roving is arranged in the region of the transition between the first roving sections and the second roving sections.The pins, which are located particularly on the axial projections of the star disks, are designed to prevent the second roving sections from slipping along the circumferential direction when the roving is inserted into the gaps. The pins fix the roving to the respective salient pole in certain areas, preventing the second roving section, guided over the winding head, from slipping along the circumferential direction during the deflection movement caused by threading.

[0013] In an advantageous development of the invention, the salient pole rotor has support rings arranged on the end faces to enclose the winding heads. Cavities beneath the support rings, in which the winding heads and the roving winding are arranged, are filled with a potting compound to form a fiber composite material containing the roving winding. The support rings or end caps, in particular, have a cylindrical shell that conforms to an outer side of the axially projecting projections of the star disks and is mechanically connected to them. A cover of the support rings, which overlaps the end faces, has filling openings through which the potting compound can be poured to further increase the supporting effect.

[0014] The embodiments presented with reference to the salient pole rotor according to the invention and their advantages apply accordingly to the electrical machine according to the invention.

[0015] The invention will now be explained in more detail using a preferred embodiment and with reference to the drawings.

[0016] They show: Fig. 1 shows a schematic perspective view of components of a salient pole rotor for an electrical machine; Fig. 2 shows an enlarged section of the salient pole rotor without a roving winding; Fig. 3 shows an enlarged section of the salient pole rotor with the roving winding; Fig. 4 shows an enlarged section of the salient pole rotor in the region of an end face of the salient pole rotor; Fig. 5 shows a cross-sectional view through a salient pole; and Fig. 6 shows a perspective view of a fully assembled salient pole rotor.

[0017] In the figures, identical and functionally identical elements are provided with the same reference numerals.

[0018] Fig. 1 shows components of a salient-pole rotor 1 for a current-excited electrical machine not shown here. The salient-pole rotor 1 has a rotor core 2, which is rotationally fixedly connected to a rotor shaft 3 for torque transmission. The rotor core 2 serves to hold and conduct a magnetic field of energizable windings 4 of the salient-pole rotor 1. To form a winding 4, wire-shaped winding conductors are wound around each salient pole 5 of the rotor core 2 and guided over star disks 6, which are arranged on opposite end faces 2a of the rotor core 2. The windings 4 form winding heads 7 on the star disks 6. To support the winding heads 7 against centrifugal forces during operation of the electrical machine, the salient-pole rotor 1 also has a support device 8.

[0019] The support device 8 has a tensioning and deflection device 9 and a roving winding 10 made of a roving 11. The roving 11 can be, for example, a plastic fiber bundle or a glass fiber bundle. Fig. 2 shows a section of the salient pole rotor 1 without the roving winding 10 and Fig. 3 a section of the salient pole rotor 4 with the roving winding 10 from a further perspective. The tensioning and deflecting device 9 has two tensioning and deflecting rollers 12, one tensioning and deflecting roller 12 each arranged on an end face 2a of the rotor core 2. Here, the tensioning and deflecting rollers 12 are fastened to the rotor shaft 3. The tensioning and deflecting rollers 12 have a plurality of guide grooves 13 arranged axially one above the other and running in the circumferential direction, via which the roving 11 can be guided past the rotor shaft 3, for example diametrically, over the winding heads 7 of the end faces 2a of the rotor core 2 and / or can be deflected along the circumferential direction when guided over the winding heads 7 of the end faces 2a of the rotor core 2.

[0020] The roving 11 has first roving sections 11a, which extend axially, and second roving sections 11b, which extend along the end faces 2a. Fig. 4 shows a section of the salient pole rotor 1 in the region of the transition between the first roving sections 11a and the second roving sections 11b. The roving 11 forms several windings arranged offset along the circumferential direction, with each winding spanning two opposing windings 4 and thus supporting two opposing salient poles 5 against the centrifugal force. Six windings are provided per salient pole pair, which is formed from two radially opposite salient poles 5. Each winding comprises two axial first roving sections 11a, with one roving section 11a being arranged on one salient pole 5 of a salient pole pair and the other roving section 11a being arranged on the other salient pole 5 of the same salient pole pair.In addition, each winding comprises two second roving sections 11b, wherein one roving section 11b is arranged on one end face 2a and the other roving section 11b is arranged on the axially opposite, other end face 2a. One roving section 11b is guided by means of the tensioning and deflection roller 12 from one salient pole 5 to the radially opposite salient pole 5 via the winding head 7 of the end face 2a past the rotor shaft 3. The other, axially opposite, end-face roving section 11b is deflected by means of the tensioning and deflection roller on the other end face 2a and thus forms a winding transition between two windings.

[0021] The axial roving sections 11a are arranged on the salient pole 5 in such a way that they are located between a pole shoe 14 of the salient pole 5 and axial

[0022] Winding conductor sections of the winding 4 wound around a rotor tooth 15 of the salient pole 5. This is particularly evident from the cross-sectional view of the salient pole rotor 1 in the area of ​​the salient pole 5 in Fig. 5 shown. Here, three windings are arranged per salient pole pair on pole shoe areas 14a, which project along the circumferential direction past the respective rotor tooth 15, so that two opposing windings are wrapped by a total of six windings.

[0023] To arrange the first roving sections 11a in an axial gap 16 located radially between the windings 4 and the pole pieces 14, the roving 11 is first deflected along the circumferential direction and then pushed circumferentially into the gap 16. To prevent the second roving sections 11b from slipping on the end faces 2a, the star disks 6 here have insertion aids 17. These fix the roving 11 at the transition point between the second roving section 11b and the first roving section 11a. The insertion aids 17 here are pins 18 projecting axially from the winding heads 7, whereby the roving 11 can be arranged between two pins 18 and thus fixed in the circumferential direction in this area. The pins 18 are arranged here on insulating parts 19 of axially projecting projections 20 of the star disks 6, which also support the winding heads 7 radially.

[0024] Fig. 6shows the fully assembled salient pole rotor 1. Cover slides 21 or slot closure wedges are arranged between two salient poles 5, closing a pole gap or slot formed between two salient poles 5. Furthermore, the salient pole rotor 1 has support rings 22, which are arranged on the axially opposite end faces 2a and are mechanically connected to the star disks 6. The support rings 22 surround the star disks 6 and thus the winding heads 7. The support rings 22 have filling openings 23, through which a cavity beneath the support rings 22, which contains, among other things, the winding heads and the roving winding 11, can be filled with a potting compound. Such a potting compound can, for example, be a potting resin, by means of which the rotor winding 4 can be further stabilized and protected.This potting compound forms a fiber composite body with the roving winding 11, which is capable of absorbing a large portion of the centrifugal forces of the winding heads 7. This makes it possible to design the additional support structures, such as the star disks 6 and the support ring 22, as thin as possible or to form them from a material optimized for cooling the salient pole rotor 1.

Claims

1. Salient pole rotor (1) for an electric machine having: - a rotor core (2) which has a rotor yoke and salient poles (5) which are arranged distributed in the circumferential direction on the rotor yoke, two salient poles (5) which lie radially opposite one another each forming a salient pole pair, and the salient poles (5) each having a rotor tooth (15) and a pole shoe (14), - magnetic field-generating windings (4) which are wound around the rotor teeth (15) of the salient poles (5) and configure winding heads (7) on opposite end sides (2a) of the rotor core (2), and - a supporting apparatus (8) for supporting the winding heads (7), wherein the supporting apparatus (8) has a tensioning and deflecting device (9) and a roving winding (10) with a roving (11), characterized in that by way of the roving (11) a plurality of windings are formed which are offset in the circumferential direction and encompass the windings (4) of in each case one salient pole pair, and the roving (11) has, to this end, axial first roving portions (11a) and end-side second roving portions (11b), the second roving portions (11b) being guided over the winding heads (7) by means of the tensioning and deflecting device (9) in order to configure a winding between salient poles (5) which lie radially opposite one another, and being deflected along the circumferential direction during guiding over the winding heads (7) in order to configure a winding transition between two windings.

2. Salient pole rotor (1) according to Claim 1, characterized in that, for each salient pole pair, the roving winding (10) has at least two windings which are arranged on pole shoe regions (14a) of the pole shoes (14) which lie opposite one another in the circumferential direction and project on the respective rotor teeth (15).

3. Salient pole rotor (1) according to Claim 1 or 2, characterized in that the roving (11) is configured as a plastic fiber bundle or as a glass fiber bundle.

4. Salient pole rotor (1) according to one of the preceding claims, characterized in that the tensioning and deflecting device (9) has two tensioning and deflecting rollers (12) which are arranged on the end sides (2a) of the rotor core (2) which lie axially opposite one another.

5. Salient pole rotor (1) according to Claim 4, characterized in that the tensioning and deflecting rollers (12) have a plurality of guide grooves (13) which are arranged axially above one another in order to deflect the second roving portions (11b) and to guide them past a rotor shaft (3) of the salient pole rotor (1).

6. Salient pole rotor (1) according to Claim 4 or 5, characterized in that a roving start of the roving is wound multiple times around one of the tensioning and deflecting rollers (12) in order to fix the roving by way of configuration of a roving tension.

7. Salient pole rotor (1) according to one of the preceding claims, characterized in that axially extending gaps (16) are configured between the windings (4) and the pole shoes (14) of the salient poles (5), in which gaps (16) the first roving portions (11a) are arranged.

8. Salient pole rotor (1) according to Claim 7, characterized in that the salient pole rotor (1) has two star disks (6) which are arranged between the end sides (2a) of the rotor core (2) and the winding heads (7), and which have insertion aids (17) for the tangential insertion of the first roving portions (11a) into the gaps (16).

9. Salient pole rotor (1) according to Claim 8, characterized in that the insertion aids (17) are configured as pins (18), projecting axially on the winding heads (7), of the star disks (6), between which the roving (11) is arranged in the region of a transition between the first roving portions (11a) and the second roving portions (11b), the pins (18) being designed to prevent slipping of the second roving portions (11b) along the circumferential direction during the insertion of the roving (11) into the gaps (16).

10. Salient pole rotor (1) according to one of the preceding claims, characterized in that the salient pole rotor (1) has supporting rings (22) which are arranged on the end sides (2a) in order to encase the winding heads (7), cavities below the supporting rings (22), in which the winding heads (7) and the roving winding (10) are arranged, being filled with a potting material in order to configure a fiber composite material which comprises the roving winding (10).

11. Electric machine for a motor vehicle with a stator and a salient pole rotor (1) according to one of the preceding claims which is mounted rotatably with regard to the stator.