Rotor having an end cap with partition walls

Abstract

The invention relates to a rotor (9, 9a, 9b) for an electric machine (1), said rotor comprising a rotor shaft (10), a laminated rotor core (11) mounted thereon, said laminated rotor core having rotor laminations and rotor slots (12, 12a, 12c) provided therein, and rotor windings (13) provided in the rotor slots (12, 12a, 12c), said rotor windings forming end-face rotor winding heads. In addition, the rotor (9, 9a, 9b) comprises pole separators (17), which radially cover the rotor slots (12, 12a, 12c), and a first end cap (15a), which axially closes the laminated rotor core (11) at the end face by means of the pole separators (17). The first end cap (15a) is equipped with first partition walls (16a, 16b), which divide a potting space provided in the rotor (9, 9a, 9b) into a plurality of potting chambers (D1, D3), each of which extends into a plurality of rotor slots (12, 12a, 12c). The invention further relates to an electric machine (1) having such a rotor (9, 9a, 9b), to a vehicle (19) having such an electric machine (1), and to a method for encapsulating such a rotor (9, 9a, 9b) using a potting compound.

Description

[0001] Rotor with an end cap with partitions

[0002] TECHNICAL AREA

[0003] The invention relates to a rotor for an electric machine, comprising a rotor shaft, a rotor lamination stack, rotor windings, pole separators, and a first end cap. The rotor lamination stack is mounted on the rotor shaft and has several axially stacked rotor laminations and rotor slots arranged therein. The rotor windings are arranged in the rotor slots, forming rotor winding heads at the end faces of the rotor lamination stack. The pole separators radially cover the rotor slots, and the first end cap axially closes the rotor lamination stack with the pole separators at a first end face of the rotor lamination stack. The invention further relates to an electric machine with a stator and a rotor of the type rotatably mounted therein, a vehicle with such an electric machine intended for propelling the vehicle, and a method for potting such a rotor with a potting compound.

[0004] STATE OF THE ART

[0005] Such a rotor, such an electric machine, such a vehicle, and such a method are each known from the prior art. By potting the rotor with a potting compound, the rotor windings are to be permanently fixed in the rotor lamination stack, and unwanted movement of the rotor windings during operation of the electric machine is to be prevented. Air inclusions, especially inhomogeneously distributed air inclusions, and the resulting imbalance of the rotor must be avoided as far as possible. The problem is that, according to the prior art, potting the rotor requires comparatively high technical effort. In particular, a vacuum chamber is used to enable potting of the rotor in an acceptable time and with satisfactory quality. DISCLOSURE OF INVENTION

[0006] One object of the invention is therefore to provide an improved rotor, an improved electric machine, an improved vehicle, and an improved method for potting a rotor. In particular, the rapid potting of the rotor with a potting compound should be made possible in a technically simpler manner, but without loss of quality.

[0007] The object of the invention is solved with a rotor of the type mentioned at the outset, in which first partition walls are provided in the first end cap, which divide a potting chamber arranged in the rotor into several potting chambers, each of which extends into several rotor grooves.

[0008] Furthermore, the problem of the invention is solved with an electric machine which has a stator and a rotor of the type mentioned which is rotatably mounted therein.

[0009] Furthermore, the problem of the invention is solved with a vehicle equipped with such an electric machine which is intended to propel the vehicle.

[0010] Finally, the object of the invention is achieved by a method for casting a rotor of the above-mentioned type, comprising the following steps:

[0011] Aligning the rotor so that the rotor shaft runs vertically, with the first end face of the rotor lamination stack pointing downwards or the first end cap positioned at the bottom,

[0012] Feeding a liquid potting compound into a rotor groove per potting chamber, which serves as a feed rotor groove, and

[0013] Curing of the potting compound. In particular, the potting compound can be fed into the potting chambers via the feed rotor grooves until the potting compound emerges from the remaining rotor grooves (all of them).

[0014] The proposed measures allow the rotor to be potted with a potting compound in a technically simple manner, particularly without the use of a vacuum chamber and without the risk of critically large air inclusions. Specifically, the rotor can be potted at atmospheric pressure. Because the liquid potting compound is fed to only one rotor groove per potting chamber, at least one rotor groove per chamber remains open, allowing excess air to escape. This means that the first end cap incorporates partitions that divide the rotor into several potting chambers, each containing at least two rotor grooves. By providing these potting chambers, unforeseen air currents within the potting area can be avoided, and the rotor can be potted quickly and reproducibly.Imbalance caused by an unevenly distributed potting compound can therefore be avoided or at least minimized. Overall, the proposed measures enable the rotor to be potted with a potting compound quickly and in a technically simpler manner than is possible with the prior art, without compromising quality.

[0015] For example, a first partition wall can rest axially against a rotor winding head to separate adjacent potting chambers. In particular, the first end cap, which is located on a first end face of the rotor lamination stack, can seal against the rotor lamination stack and the rotor shaft. This prevents unwanted flow of the potting compound between the potting chambers and out of the potting area. In this context, the term "sealing" means, in particular, that the potting compound is prevented from overcoming a seal. Further sealing (against less viscous media and gases) is not required but may be provided. Specifically, the first partition walls can each be arranged between two adjacent rotor slots, for example, centrally.

[0016] In general, hardening can be achieved by passively waiting for a hardening time or by active measures, such as heating the rotor.

[0017] Further advantageous embodiments and developments of the invention will become apparent from the dependent claims and from the description in conjunction with the figures.

[0018] For example, a potting chamber may extend across exactly two or exactly three rotor slots, or each potting chamber may contain exactly two or exactly three rotor slots. If two rotor slots are present, one rotor slot per potting chamber remains open for air escape; if three rotor slots are present, two rotor slots per potting chamber remain open for air escape. In the case of three rotor slots, it is particularly advantageous if the feed rotor slot is located between the two remaining rotor slots, as this allows for highly reproducible potting. In other words, in this case, a potting chamber extends across exactly three rotor slots, with the middle of the three serving as the feed rotor slot into which the potting compound is fed.

[0019] It is also advantageous if a first partition wall has an elastic section that rests against the rotor winding head, or if it is entirely elastic. This allows for a particularly effective seal against the rotor winding head.

[0020] It is further advantageous if the rotor has a second end cap which axially closes off the rotor lamination stack with the pole separators at a second end face opposite the first end face, wherein second partition walls are provided in the second end cap. This allows the rotor to also be potted with the potting compound at the second end face. The technical teaching disclosed for the first partition wall applies analogously. The second partition walls can therefore, in particular, be elastically designed or each have an elastic section that rests against the second rotor winding head. In particular, the second end cap can also provide a sealing connection to the rotor lamination stack and the rotor shaft.

[0021] It is also advantageous if each first partition wall is assigned a second partition wall that is axially aligned with the first partition wall. In this way, the potting chambers are continued in the second end cap, so that unintentional flow of the potting compound from one potting chamber into an adjacent potting chamber via the second end cap can be avoided.

[0022] Furthermore, it is advantageous if each rotor groove is assigned a different opening in the second end cap. This allows the rotor to be potted smoothly and without interference in the potting process between adjacent rotor grooves.

[0023] It is also particularly advantageous if each opening is separated from adjacent openings by secondary partitions. This prevents the unintentional flow of the potting compound from one rotor groove into an adjacent rotor groove via the second end cap.

[0024] The proposed method also offers the advantage of feeding the potting compound through the openings associated with the feed rotor grooves. This allows for a particularly reliable seal between the feed tube and the rotor, especially if both the feed tube and the feed opening have a circular cross-section. In particular, the potting compound can be fed through the openings associated with the feed rotor grooves until it overflows or threatens to overflow from the remaining openings.

[0025] Furthermore, it is advantageous to stop the supply of the potting compound after the first end cap has been completely filled, and to resume the supply after a holding period. This ensures that any air that may remain in the first end cap after it has been filled can rise safely and enter the rotor slots adjacent to the supply rotor slots.

[0026] Finally, it is also advantageous to increase the feed rate of the potting compound after the first end cap has been completely filled. This allows the rotor to be potted particularly quickly, as the risk of air remaining in the potting compound as it rises into the rotor slots adjacent to the feed slots is virtually eliminated.

[0027] BRIEF DESCRIPTION OF THE FIGURES

[0028] Exemplary embodiments of the invention are shown in the accompanying schematic figures. These show:

[0029] Fig. 1 shows a half-section through an exemplary and schematically represented electrical machine;

[0030] Fig. 2 shows an exemplary end cap in oblique view;

[0031] Fig. 3 shows an exemplary rotor with two rotor slots per potting chamber with the second end cap removed; Fig. 4 shows the rotor from Fig. 3 with the second end cap fitted;

[0032] Fig. 5 shows an exemplary rotor with three rotor slots per potting chamber and

[0033] Fig. 6 shows an exemplary vehicle with an electric machine of the proposed type.

[0034] DETAILED DESCRIPTION OF THE INVENTION

[0035] It is stated in the introduction that identical parts in the different embodiments are provided with the same reference numerals or component designations, possibly with different indices. The disclosure of a component contained in the description can be applied analogously to another component with the same reference numeral or component designation. Furthermore, the positional indications chosen in the description, such as "top," "bottom," "back," "front," "side," and so on, refer to the figure directly described and illustrated and, in the event of a change in position, must be applied analogously to the new position.

[0036] Fig. 1 shows a half-section through a schematically represented electric machine 1 with a machine housing 2 comprising a stator housing 3, a first (rear) end shield 4, and a second (front) end shield 5. However, the machine housing 2 could also have a different design and include more or fewer parts than shown in Fig. 1. For example, the stator housing 3 could be cup-shaped, and the first or second end shield 4, 5 could be omitted.

[0037] Furthermore, the electric machine 1 comprises a stator 6 arranged in the stator housing 3, which has a stator lamination stack 7 (not shown in detail) and stator windings 8 arranged in the stator lamination stack 7, of which only the stator winding heads are visible in Fig. 1. In addition, the electric machine 1 comprises a rotor 9, which has a rotor shaft 10 and a rotor lamination stack 11 arranged on the rotor shaft 10, with several axially stacked rotor laminations, which are not shown in detail in Fig. 1. The rotor lamination stack 11 has several rotor slots 12 in which rotor windings 13 are arranged, forming rotor winding heads at the end faces B1, B2 of the rotor lamination stack 11. The rotor shaft 10 is rotatably mounted about a rotor axis or stator axis A relative to the stator 6 by means of (rolling) bearings 14a, 14b.Specifically, the first bearing 14a is located in the first bearing shield 4 and the second bearing 14b is located in the second bearing shield 5.

[0038] Furthermore, the electric machine 1 comprises a first end cap 15a, which axially closes the rotor lamination stack 11 with the pole separators 17 at a first end face B1 of the rotor lamination stack 11, and an optional second end cap 15b, which axially closes the rotor lamination stack 11 with the pole separators 17 at a second end face B2 opposite the first end face B1. The pole separators 17 radially cover the rotor slots 12 and are not visible in Fig. 1, but are shown in detail in Figs. 3 to 5.

[0039] Figure 2 shows an exemplary first end cap 15a in an oblique view from the inside. The first end cap 15a includes first partitions 16a and 16b, each of which in this example has an optional elastic section C. In the assembled state, this section rests axially against the first rotor winding head at the first end face B1, particularly sealing against a potting compound. The central bore in the first end cap 15a can also provide a seal against the rotor shaft 10 for the potting compound. The second end cap 15b can be constructed similarly and include second partitions, each of which can have an optional elastic section C. In the assembled state, this section rests axially against the second rotor winding head at the second end face B2, particularly sealing against the potting compound. A central bore in the second end cap 15b can also provide a seal against the rotor shaft 10 for the potting compound.The first partitions 16a, 16b and the second partitions can also be made entirely of an elastic material. Figures 3 and 4 further show an exemplary rotor 9a in oblique view, Figure 4 with both end caps 15a, 15b mounted, and Figure 3 with the second end cap 15b removed. The first partitions 16a, 16b of the first end cap 15a divide a potting chamber arranged in the rotor 9a into several potting chambers D1 to D3, each of which extends into several rotor grooves 12a to 12c. In other words, the first partitions 16a, 16b divide the rotor 9a into several potting chambers D1 to D3, in each of which at least two of the rotor grooves 12a to 12c are arranged. In the example shown in Figs. 3 and 4, each of the casting chambers D1 ..D3 comprises exactly two rotor grooves 12a..12c. The boundaries between the casting chambers D1..D3 are indicated by dashed lines in Figs. 3 and 4.The partitions 16a, 16b of the first and second end caps 15a, 15b are also located at these boundaries. That is, each second partition of the second end cap 15b is associated with a first partition 16a, 16b of the first end cap 15a, which is flush with the first partition 16a, 16b. In particular, the first partitions 16a, 16b and / or the second partitions can each be arranged centrally between two adjacent rotor slots 12a..12c, as is the case in Figures 3 and 4. Furthermore, the second end cap 15b includes openings E1 ..E3', with each rotor slot 12a..12c being associated with a different opening E1 ..E3' arranged in the second end cap 15b.

[0040] In the example shown in Figures 3 and 4, the rotor 9a comprises an end-face winding cage 18, which, like the pole separators 17, can be made of plastic. In particular, such a winding cage 18 can be provided on both end faces B1, B2, and in particular, the winding cage 18 or the winding cages 18 can be connected to the pole separators 17. For example, two such combined components can be formed in a semi-shell shape and inserted into the rotor lamination stack 11.

[0041] The rotor 9a shown in Figures 3 and 4 is a six-pole rotor, resulting in three potting chambers D1 to D3 in this example. However, other configurations are also possible (see in particular Figure 5), or rotors with other numbers of poles can also be divided into potting chambers D1 to D3 in the manner shown.

[0042] The potting of rotor 9a with a potting compound can now be carried out by the following steps.

[0043] Aligning the rotor 9a so that the rotor shaft 10 runs vertically, with the first end face B1 of the rotor lamination stack 1 1 pointing downwards or the first end cap 15a being arranged at the bottom,

[0044] Feeding a liquid potting compound into a rotor groove 12a..12c per potting chamber D1 ..D3, which serves as a feed rotor groove 12a..12c, and hardening of the potting compound.

[0045] Because the liquid potting compound is fed to only one feed rotor groove 12a..12c per potting chamber D1 ..D3, at least one rotor groove per potting chamber D1 ..D3 remains open, allowing excess air to escape. The feeding of the potting compound and the escape of the air are indicated by arrows in Figures 3 and 4. By providing potting chambers D1 ..D3, the potting of the rotor 9a can be carried out quickly and reproducibly. Imbalance caused by an unevenly distributed potting compound can therefore be avoided or at least minimized. In particular, the potting compound can be fed to the potting chambers D1 ..D3 via the feed rotor grooves 12a..12c until the potting compound exits the remaining rotor grooves (all of them) and the rotor 9a is thus completely potted. Furthermore, the potting process can be carried out particularly at atmospheric pressure (i.e., without the use of a vacuum chamber).The potting compound can be cured passively by waiting for a specific curing time or by active measures such as heating the rotor 9a. While potting can, in principle, be carried out without the second end cap 15b, it is advantageous to do so with the second end cap 15b already installed, as shown in Fig. 4. In this case, the potting compound is fed through the openings E1 to E3 associated with the feed rotor grooves 12a to 12c. The remaining openings E1 to E3 serve as exhaust vents. Specifically, the potting compound can be fed into the potting chambers D1 to D3 via the openings E1 to E3 until it flows out of all remaining openings E1 to E3, thus completely potting the rotor 9a, including the second end cap 15b. By providing feed openings E1 ..E3 can provide a particularly reliable seal between a feed tube, through which the potting compound is supplied, and the rotor 9a, especially if both the feed tube and a feed opening E1 ..E3 have a circular cross-section.

[0046] In an advantageous embodiment of the proposed method, the supply of the potting compound can be stopped after the first (lower) end cap 15a has been completely filled with the potting compound, and the supply can be resumed after a holding period. This ensures that any air that may temporarily remain in the first end cap 15a after it has been filled can rise safely and enter the rotor slots remaining next to the feed rotor slots 12a..12c.

[0047] In a further advantageous embodiment of the proposed method, the feed rate of the potting compound can be increased after the first (lower) end cap 15a has been completely filled with the potting compound. This allows the potting of the rotor 9a to be carried out particularly quickly, as the risk of air remaining in the potting compound as it rises into the rotor slots adjacent to the feed rotor slots 12a..12c can be practically eliminated. It is also particularly advantageous if each opening E1 ..E3' is separated from adjacent openings E1..E3" by secondary partitions. This prevents unintentional flow of the potting compound from a feed rotor slot 12a..12c into an adjacent rotor slot via the second end cap 15b.

[0048] Fig. 5 shows another example of a rotor 9b, which is very similar to the rotor 9a shown in Figs. 3 and 4 and for which the technical teaching disclosed for rotor 9a is applicable mutatis mutandis. In contrast to rotor 9a, in rotor 9b a potting chamber D1, D2 extends into exactly three rotor grooves 12a..12c. That is, rotor 9b has a total of two potting chambers D1, D2 with three rotor grooves 12a..12c per potting chamber D1, D2.

[0049] The potting of rotor 9b with the potting compound is carried out in a very similar manner to the potting of rotor 9a. In contrast, a potting chamber D1, D2 comprises, in addition to one feed rotor groove 12 and one feed opening E1, E2 respectively, two remaining rotor grooves 12 and two remaining openings ET, E1", E2', E2", the remaining openings E1', E1', E2', E2" functioning as exhaust openings.

[0050] It is advantageous if the middle of the three rotor grooves 12, 12a..12c serves as the feed rotor groove 12a, 12b, and the middle of the openings E1 ..E2" serves as the feed opening E1 , E2, to which the potting compound is fed. In this case, the air can escape particularly well from the two remaining rotor grooves 12 and the exhaust openings ET, E1", E2', E2".

[0051] Figure 6 shows the electric machine 1 installed in a vehicle 19. The vehicle 19 has two axles, one of which is driven. Specifically, the electric machine 1 is connected to the half-axles 21 of the rear axle via an optional transmission 20. The driven wheels 22 are mounted on the half-axles 21. The vehicle 19 is driven at least partially or temporarily by the electric machine 1. That is, the electric machine 1 can serve as the sole drive for the vehicle 19 or, for example, be used in conjunction with an internal combustion engine (hybrid drive).

[0052] In conclusion, it is noted that the scope of protection is determined by the patent claims. However, the description and drawings are to be used for the interpretation of the claims. The features contained in the figures can be freely exchanged and combined. In particular, it is also noted that the depicted devices may, in reality, comprise more or fewer components than shown. In some cases, the depicted devices or their components may also be shown not to scale and / or enlarged and / or reduced in size.

[0053] Reference symbol list

[0054] 1 electric machine

[0055] 2 machine housings

[0056] 3 Stator housings

[0057] 4 rear bearing plate

[0058] 5 front bearing plate

[0059] 6 Stator

[0060] 7 Stator lamination stack

[0061] 8 Stator winding

[0062] 9, 9a, 9b Rotor

[0063] 10 Rotor shaft

[0064] 11 Rotor lamination package

[0065] 12 Rotor slots

[0066] 12a..12c Feed rotor groove

[0067] 13 Rotor winding

[0068] 14a, 14b (rolling) bearings

[0069] 15a, 15b End cap

[0070] 16a, 16b Partition wall

[0071] 17 pole separators

[0072] 18 winding cages

[0073] 19 vehicles

[0074] 20 gearboxes

[0075] 21 Half-axis

[0076] 22 wheel

[0077] A rotor axis

[0078] B1, B2 Front

[0079] C elastic section partition

[0080] D1..D3 Casting chamber

[0081] E1..E3 1 Front opening

Claims

Patent claims 1. Rotor (9, 9a, 9b) for an electric machine (1) comprising a rotor shaft (10), a rotor lamination stack (11) mounted on the rotor shaft (10) with several axially stacked rotor laminations and rotor slots (12, 12a..12c) arranged therein, Rotor windings (13) which are arranged in the rotor slots (12, 12a..12c) and form rotor winding heads on the end faces (B1 , B2) of the rotor lamination stack (11 ), Pole separators (17) radially covering the rotor slots (12, 12a..12c), and a first end cap (15a) axially closing the rotor lamination stack (11) with the pole separators (17) at a first end face (B1) of the rotor lamination stack (11), characterized in that first partition walls (16a, 16b) are provided in the first end cap (15a) which divide a potting chamber arranged in the rotor (9, 9a, 9b) into several potting chambers (D1 ..D3), each of which extends into several rotor slots (12, 12a..12c).

2. Rotor (9, 9a, 9b) according to claim 1 , characterized in that a potting chamber (D1 ..D3) extends into exactly two or exactly three rotor grooves (12, 12a..12c).

3. Rotor (9, 9a, 9b) according to claim 1 or 2, characterized in that a partition (16a, 16b) is axially abutted against a rotor winding head.

4. Rotor (9, 9a, 9b) according to claim 3, characterized in that the partition (16a, 16b) has an elastic section (C) which rests against the rotor winding head.

5. Rotor (9, 9a, 9b) according to one of the preceding claims, characterized by a second end cap (15b) which axially closes off the rotor lamination stack (11 ) with the pole separators (17) at a second end face (B2) opposite the first end face (B1 ), wherein second partitions are provided in the second end cap (15b).

6. Rotor (9, 9a, 9b) according to claim 5, characterized in that each first partition (16a, 16b) is associated with a second partition which is axially aligned with the first partition (16a, 16b).

7. Rotor (9, 9a, 9b) according to claim 5 or 6, characterized in that each rotor groove (12, 12a..12c) has another opening (E1..E3) arranged in the second end cap (15b). 1 ) is assigned.

8. Rotor (9, 9a, 9b) according to claim 7, characterized in that each opening (E1..E3) 1 ) with second partition walls from adjacent openings (E1..E3) 1 ) is separated.

9. Electric machine (1 ) with a stator (6) and a rotor (9, 9a, 9b) rotatably mounted therein according to one of claims 1 to 8.

10. Vehicle (19) with an electric machine (1 ) according to claim 9, which is provided for driving the vehicle (19).

11. Method for potting a rotor (9, 9a, 9b) according to one of claims 1 to 8, characterized by the steps Aligning the rotor (9, 9a, 9b) so that the rotor shaft (10) runs vertically, with the first end face (B1) of the rotor lamination stack (11) pointing downwards, supplying a liquid potting compound into a rotor groove (12, 12a..12c) per potting chamber (D1..D3), which serves as a feed rotor groove (12a..12c), and Curing of the potting compound.

12. Method according to claim 11, characterized in that the rotor is configured according to claim 7 or 8 and the potting compound is supplied through the openings (E1..E3) associated with the feed rotor grooves (12a..12c).

13. Method according to claim 11 or 12, characterized in that a potting chamber (D1..D3) extends into exactly three rotor grooves (12, 12a..12c), wherein the middle of the three rotor grooves (12, 12a..12c) serves as a feed rotor groove (12a..12c) to which the potting compound is supplied.

14. Method according to any one of claims 11 to 13, characterized in that the supply of the potting compound is stopped after the first end cap (15a) has been completely filled with the potting compound and the supply of the potting compound is resumed after a holding time. 15.Method according to one of claims 1 to 14, characterized in that the speed for supplying the potting compound is increased after the first end cap (15a) has been completely filled with the potting compound.

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