WO2013045240A2

WO2013045240A2 - Electric machine having a stator with a variable slot spacing

Info

Publication number: WO2013045240A2
Application number: PCT/EP2012/067287
Authority: WO
Inventors: Norbert WÖHNER
Original assignee: Siemens Aktiengesellschaft
Priority date: 2011-09-28
Filing date: 2012-09-05
Publication date: 2013-04-04
Also published as: CN103931082A; DE102011083577A1; WO2013045240A3; CN103931082B

Abstract

An electric machine has a stator (1) and a rotor (2). The stator (1) is arranged around an axis of rotation (4) and extends in the direction of the axis of rotation (4) from a first axial end (5) via a central region (6) to a second axial end (7). The stator (1) has slots (8), which each extend from the first to the second axial end (5, 7) of the stator (1). The windings (11) of a three-phase winding system are arranged in the slots (8). The slots (8) are delimited radially outwards by a respective slot base (10). The slots (8) form slot groups (12), when viewed around the axis of rotation (4). A radial spacing (r1, r2, r3) which the slot bases (10) have from the axis of rotation (4) at least at the axial ends (5, 7) of the stator (1) is constant within the respective slot group (12), but varies from slot group (12) to slot group (12).

Description

description

Electric machine with stator with variable slot spacing The present invention relates to an electrical machine,

wherein the electric machine has a stator and a rotor,

wherein the stator is disposed about an axis of rotation of the electric machine and extends in the direction of the rotation axis from a first axial end via a central region to a second axial end of the stator,

the stator having a plurality of grooves each extending from the first to the second axial end of the stator,

wherein the windings of a three-phase winding system are arranged in the slots,

- wherein the grooves are bounded radially outwardly by a respective groove bottom,

- Wherein the grooves seen around the rotation axis around groove ^¬ form groups.

Such an electric machine is known for example from DE 10 2005 037 375 AI or DE 10 2005 002 364 AI.

The production of stator windings for multi-phase electrical machines - in particular three-phase electrical Maschi ^¬ NEN -, for example asynchronous motors, is very complex and connected to a high proportion of manual labor.

Furthermore, many operations are required to make a stator. The stator lamination usually has grooves on the inner bore into which the partial coils are inserted. The grooves are in the prior art, all evenly close to the inner bore.

By means of novel needle winding methods, it is possible to insert the individual windings (individual coils) directly into the stator. wind up, with end disks take up the winding head. For each phase, a separate end plate is required, so that a total of three layers are placed on each other. The Endschei ^¬ ben make sure that after winding a phase, the remaining, not yet wound grooves remain free. The three individual phases are in the winding heads on top of each other, so that relatively long windings arise, which can be cooled only badly. Furthermore, the individual phases have paths of different lengths, so that the ohmic resistances are also different from each other.

Another possibility is to wrap the individual coils in an end plate directly or by means of auxiliary bodies. However, this procedure is very complicated.

The object of the present invention is to provide an electric machine which is easy to manufacture, has a compact design and is operable efficiently. The task is accomplished by an electric machine with the

Characteristics of claim 1 solved. Advantageous ^Ausgestaltun conditions of the electric machine according to the invention are the subject of the dependent claims 2 to 14. According to the invention, an electrical machine of the type mentioned in that a radial distance, the groove bottoms of the rotation axis aufwei ^¬ sen, at least at the axial Although the ends of the stator are constant within the respective groove group, they vary from one groove group to the next groove group.

It is possible that the respective radial distance which the groove bottoms have from the axis of rotation is the same in the middle region as at the axial ends. In this case, can be used for making the stator lamination identical stator plates ^¬. Alternatively, it is possible that the respective radial Ab ^¬ stand, which have the groove bottoms of the rotation axis, at least for those grooves whose groove bottoms at the axial ends of the stator have the greatest radial distance from the rotation axis, in the central region is smaller than at the axial ends. In particular, in this case, the respective radial distance that the groove bases have from the axis of rotation on ^¬ may be the same for all grooves in the central region. With this configuration, the magnetic coupling between the stator and the rotor can be optimized.

Particularly preferred is a combined result Pre ^¬ hens example. Because usually, the stator has a stator ^¬ sheet package and two end plates, the end plates are placed at the axial ends of the stator lamination. It is possible that the grooves within the Statorblechpa ^¬ kets seen both in the axial direction and around the axis of rotation around a uniform radial distance from the axis of rotation. In this case, the widening takes place from the uniform radial distance to larger radial distances in the end disks.

The groups often include more than one groove. In particular, they may comprise two, three or four grooves.

It is possible that those grooves of a respective groove group, which are not seen around the axis of rotation around ei ^¬ ner the respective groove group centrally dividing first Axialebe ^¬ ne, radially inwardly have a groove opening, which seen around the axis of rotation between the first axial plane and a respective central groove dividing the second axial plane is arranged. By this procedure, on the one hand facilitates the winding process and on the other hand, the magnetic flux can be optimized.

The procedure described is last only useful for grooves with respect to the first axial eccentrically on ^¬ sorted. If, however, the groups of grooves respectively an odd number of grooves comprise - this also applies to the case that the groups each only a single groove around ^¬ - has the middle groove of the respective groove group preferably radially inward on a slot opening, which arranged centrally with respect to the corresponding groove is. In the case ^¬ sem the groove bottom of the central groove preferably has a projecting radially inward nose.

In a preferred embodiment of the electrical machine is provided that the stator seen in the regions in which the grooves are arranged, the groove bottoms have the smallest radial distance from the axis of rotation around the axis of rotation, in its radially outer region extending in the axial direction recesses , This configuration in particular the amount of be ^¬ nötigtem material of the stator lamination can be minimized.

It is possible and even preferred that at least one of the recesses in cross-section, viewed transversely to the axis of rotation, is designed as a closed recess. In this case, the at least one closed recess can serve to guide a cooling medium.

Regardless of whether a recess is closed or not, a communication cable can be arranged in the respective recess.

Due to the inventive design of the grooves, it is particularly possible that the windings each have a winding overhang at both axial ends of the stator and that the winding overhangs of the windings do not intersect at the respective axial end of the stator.

The above-described characteristics, features and advantages of this invention, as well as the manner in which they are achieved, will become clearer and more clearly understood in connection with the following description of the embodiments. games, which are explained in more detail in connection with the drawings. This show in a schematic representation

1 shows an electrical machine in longitudinal section,

2 shows a plan view of a stator,

3 shows the representation of FIG. 2 with a single marked phase,

4 to 6 each show a section through a possible ^{Ausgestal ¬} tion of the stator of Figure 2,

7 to 9 each show a section through an alternative mögli ^¬ che embodiment of the stator of Figure 2,

10 to 12 each show a section through a further alternative possible embodiment of the stator of FIG. 2,

13 and 14 each have a groove in cross-section,

FIG. 15 shows a modification of the stator of FIG. 2, FIG.

16 shows a plan view of an end plate and

17 shows a section through the end plate.

According to FIGS. 1 to 3, an electric machine has a stator 1 and a rotor 2. The rotor 2 is arranged on a rotor shaft 3, which in turn is rotatably mounted. The rotor 2 is therefore rotatable about a rotation axis 4.

Except as described below, the terms "axial", "radial" and "tangentially" are used, they are always based on the rotational property, ^¬ se. 4 "Axial" means a direction parallel to the Ro ^¬ tationsachse 4. "Radial" means a direction "Tangential" means a direction orthogonal to the axial direction and orthogonal to the radial direction, ie at a constant radial distance in a circle around the axis of rotation 4 around.

The stator 1 is arranged around the rotation axis 4. It extends in the axial direction from a first axial end 5 via a central region 6 to a second axial end 7. The stator 1 has a multiplicity of grooves 8. The illustrated number of grooves 8, ie 36 grooves 8, however, is pure exemplary. Alternatively, there could be more or fewer than 36 slots 8, for example 12, 24, 48, 60, 72 slots 8, etc. The slots 8 each extend from the first to the second axial end 5, 7 of the stator 1. They are in tangential direction ^¬ tion of respective groove walls 9 and radially outwardly bounded by a respective groove bottom 10. The windings 11 of a three-phase winding system are arranged in the slots 8, with only the windings 11 for one phase of a three-phase three-phase winding system being illustrated in FIG. The other two phases, not shown, are distributed in an analogous manner to the not shown in Figure 3 grooves 8.

According to FIG. 3, the electric machine is designed as a four-pole electric-electric machine. This representation is per ^¬ but only purely exemplary. The electrical machine may also be formed as a two-pole, six-pole, eight pole, etc. electrical ^¬ specific machine.

Grooves 8 form groove groups 12 in the tangential direction. Groove groups 12 are defined by a radial distance r 1, r 2, r 3 within groove group 12, which groove bottoms 10 of grooves 8 of respective groove group 12 have from axis of rotation 4 Although at the axial ends 5, 7 of the stator 1 is the same for all grooves 8 of the respective groove group 12, the radial distance rl, r2, r3 within the respective groove group 12 is constant, the radial distance rl, r2, r3, however from groove group 12 to groove ^¬ group 12 varies, that is not constant or is not the ^¬ same. In order to achieve the just explained variation of the radial distance rl, r2, r3, there are various possibilities. Thus, it is possible, for example as shown in FIGS 4, 5 and 6, that the respective radial distance rl, r2, r3, to the Nutbö ^¬ 10 having the axis of rotation 4, in the central area 6 is the same as at the axial ends 5, 7 In particular, the respective radial distance r1, r2, r3 can thus be constant along the respective groove 8. This embodiment offers the particular advantage that the stator laminations 13 of the stator lamination stack 14 of the stator 1 can all be made uniform.

Alternatively, it is possible according to the Figures 7, 8 and 9 that the respective radial distance rl, r2, r3, to the Nutbö ^¬ 10 may include from the rotation axis 4, at least for the ^¬ jenigen grooves 8, the groove bottoms 10 axial to the Ends 5, 7 of the stator 1 have the greatest radial distance r3 of the rotation ^¬ onsachse 4, is smaller in the central region 6 than at the axial ends 5, 7. Preferably, this - see FIG 8 - even with those grooves 8 of the case whose groove bottoms 10 at the axial ends 5, 7 of the stator 1 have a radial distance r2 from the axis of rotation 4, which is between the largest and the smallest radial distance r3, rl of the groove bottoms 10 at the axial ends 5, 7 of the stator 1. This Ausgestal ^¬ processing has the advantage that the force exerted by the stator 1 to the Ro ^¬ tor 2 electromotive force of the different phases for all windings 11 is almost constant with equal Bestro- mung of the windings. 11

The extent to which the greatest radial distance r3 or the larger radial distances r3, r2 are reduced in the central region 6 can, in principle, be chosen as desired. Before ^¬ preferably the minimal radial distance rmin, the groove 10 having ^¬ floors in the middle area 6 of the axis of rotation 4, for all the grooves 8 the same. In particular, it can be equal to the smallest radial distance r 1 that the groove bottoms 10 have at the axial ends 5, 7 of the stator 1 from the axis of rotation 4. FIGS. 10, 11 and 12 show a special possibility of the last-mentioned embodiment of the stator 1. According to FIGS. 10 to 12, the stator 1 -as in the embodiments of FIGS. 4 to 6 and 7 to 9 -has a laminated stator core 14. Furthermore, the stator 1 - as in the Ausgestal ^¬ lines of Figures 4 to 6 and 7 to 9 also - two end plates 15, 16, which are placed on the stator iblechpaket 14 at the axial ends 5, 7. According to FIGS. 10 to 12, however, the middle region 6 is identical to the axial extension of the stator lamination packet 14. In this range, ie within the stator lamination stack 14, each groove 8 to a kon ^¬ constants radial distance rc from the rotation axis. 4 Seen in the axial direction, the radial distance rc is thus constant. The radial distance rc is within the stator lamination packet 14 but also for all grooves 8 uniformly the same. Also about the rotation axis 4 around seen, the radial distance of the groove bottoms 8 rc from the rotation axis 4 is thus a ^¬ uniformly the same or constant. The uniform radial From ^¬ was rc is usually the minimum radial distance rmin identical. Varying the radial distances rl, r2, r3 at the axial ends 5, 7 is thus realized by a entspre ^¬ sponding embodiment of the end discs 15 °. These have for the individual groove groups 12 differently configured - in particular different steep and / or different lengths - ramps 16, which cause the corresponding variation of the radial distance rl, r2, r3 at the axial ends 5, 7.

It is possible that the groove groups 12 each comprise only a single groove 8. This embodiment may be useful in particular for relatively high-pole electrical machines. Often, however, the groove groups 12 each comprise more than one groove 8. For example, the present invention is illustrated in FIGS 2, 3, 15 and 16 with reference to a four-pole electric machine with three grooves 8 per groove group 12. Al ternatively ^¬ the electrical machine may have only two slots per 8 slot group 12, for example as a four-pole elekt ^¬ generic machine with a total of 24 grooves 8 or as a six-pole electric machine with a total of 36 grooves 8 may be formed. Alternatively again, the electric machine may be configured as a two pole electric machine with 24 slots or 8 ^¬ than four-pole electric machine with 48 slots. 8 In these two cases, the groove groups 12 would each comprise four grooves 8. Other embodiments are possible.

Regardless of the specific grouping of the grooves 8 exists for each groove group 12, a respective axial plane 17, hereinafter referred to as the first axial plane 17. The respective first axial plane 17 contains the axis of rotation 4 and shares in the tangential direction the respective groove group 12 in the middle. Furthermore, for each groove 8 there is a respective axial plane 18, hereinafter referred to as second axial plane 18. The second axial plane 18 is defined by the fact that it contains the Ro ^¬ tationsachse 4 and the respective groove 8 divides centrally.

It is possible and customary in the prior art for each groove 8 to be symmetrical with respect to the respective second axial plane 18. In particular, the grooves 8 according to FIG. 13 can have radially inwardly a slot opening 19 which is arranged centrally with respect to the corresponding second axial plane 18 and thus with respect to the corresponding slot 8. In the context of the present invention, this embodiment is also possible. However, it is preferred that this Aus ^¬ design is realized only if the groove groups 12 each comprise an odd number of grooves 8, for example, ^¬ only a single groove 8 or three grooves 8, five grooves 8, etc. Furthermore, is preferably Also in this case, the corresponding configuration only taken in the middle groove 8 of the respective groove group 12. This can be seen in particular from FIGS. 2 and 3.

The groove bottom 10 of the central groove 8 of the respective groove group 12 may continue to have in this case, according to FIG 13, a radially inwardly projecting nose 20. The nose 20 is preferably ^¬ symmetrically formed and arranged with respect to the respective second axial plane 18. Those grooves 8 of the respective groove group 12, which do not lie on the first Axialebe ^¬ ne 17 seen around the rotation axis 4, ie are arranged eccentrically with respect to the respective first axial plane 17, according to FIGS 2, 3 and 14 radially inside a respective groove ^¬ opening 19, which is seen around the rotation axis 4 around between the first axial plane 17 of the respective groove group 12 and the respective second axial plane 18 of the corresponding groove 8 is arranged. The respective groove 8 thus has, according to FIG. 14, preferably the shape of a flag or a flag

Ship helms on.

It is possible that the stator 1 seen in cross section transverse to the rotation axis 4 a completely convex - insbesonde ^¬ re circular - outer contour, the cross section of the stator 1 - with the exception of the grooves 8 and the recess for the rotor 2 - completely closed is. Preferably, however, the stator 1 as shown in FIG 15 around the axis of rotation 4 seen in those areas in which the grooves 8 are arranged, the groove bottoms 10 at the axial ends 5, 7 of the stator 1 have the lowest radial distance rl from the axis of rotation 4 , in its radially outer region recesses 21, 22, which extend in the axial direction. It is possible that the recesses 21, 22 are open radially outward. It is also possible that the recesses 21, 22 are closed radially outward. Mixed forms are also possible, so that both radially outwardly from open ^¬ recesses 21 and radially outwardly closed Ausneh- rules 22 are available. An example of such

Mixed form is shown in FIG.

Insofar as radially outwardly closed recesses 22 are present, they can serve to guide a cooling medium-in particular air. Alternatively, in at least one of these recesses 22, a communication cable 23 may be arranged. As far as radially outwardly open recesses 21 are present, in at least one of these recesses Communication cable 23 may be arranged. Alternatively it can be arranged in at least one of these recesses 21, a pipe 24 that in turn the leadership of a cooling medium - in particular water or air - is used.

According to FIG. 17, the windings 11 each have a winding overhang 25 at both axial ends 5, 7 of the stator 1. The Ge ^¬ totality of the winding overhangs 25 corresponding to the two axi ^¬ alen winding heads of the three-phase winding system. Due to the inventive embodiment, it is possible according to the Dar ^¬ position shown in FIGS 16 and 17, that the winding overhangs ^¬ 25 do not cross at the respective axial end 5, 7 of the stator. 1 This is true even when the per ^¬ stays awhile end plate 15 is a single layer formed all interturn overhangs 25 thus extend in a single plane, that is, not being mutually offset in height in the axial direction.

The present invention has many advantages. In particular, the winding operation can be automatic ^¬ tisiert easily and reliably. This is particularly true when first the grooves are wound 8, which have, at the axial ends 5, 7 of the largest radial distance r3 from the rotational axis 4 on ^¬, the grooves 8 with the corresponding second largest radial distance r2, etc .. The Final wiring of the three-phase winding system is easy. Furthermore, it ^¬ adopt an improved dissipation of heat loss from the winding overhangs 25. Although the invention in detail by the preferred embodiment has been illustrated and described in detail, the invention is not ^¬ limited by the disclosed examples and other variations may be derived therefrom by the skilled artisan without departing from the scope of the invention.

Claims

claims

1. Electric machine,

- wherein the electric machine has a stator (1) and a rotor (2),

- wherein the stator (1) about a rotation axis (4) of the elekt ^¬ step machine around and extending in the direction of the axis of rotation (4) from a first axial end (5) through a central region (6) (to a second axial end 7) of the stator (1),

- wherein the stator (1) has a plurality of grooves (8) extending from the first to the second axial end (5, 7) of the stator (1),

- Wherein the windings (11) of a three-phase winding system are arranged in the grooves (8),

- Wherein the grooves (8) are bounded radially outwardly by a respective groove bottom (10),

the grooves (8) forming groove groups (12) around the rotation axis (4),

- Wherein a radial distance (rl, r2, r3), the groove bottoms

(10) of the rotational axis (4), at least at the axial ends (5, 7) of the stator (1) while within the respective groove group ^¬ (12) is constant, but from groove group (12) to groove group (12) varied.

2. Electrical machine according to claim 1,

characterized in that the depending ^¬ stays awhile radial distance (rl, r2, r3), the having groove bottoms (10) from the rotational axis (4), in the central region (6) is the same as at the axial ends (5, 7).

3. Electrical machine according to claim 1,

characterized in that the depending ^¬ stays awhile radial distance (rl, r2, r3) which the groove bottoms (10) from the axis of rotation (4), at least for those grooves (8), the groove bottoms (10) at the axial ends (5 , 7) of the stator (1) the largest radial distance (r3) of the Have rotational axis (4), in the central region (6) is smaller than at the axial ends (5, 7).

4. Electrical machine according to claim 3,

characterized in that each of the stays awhile ^¬ radial distance (rl, r2, r3), the having groove bottoms (10) from the rotational axis (4), for all the grooves (8) in the central region (6) is the same.

5. Electrical machine according to claim 3 or 4,

characterized in that the stator (1) has a laminated stator core (14) and two end disks (15), that the end disks (15) are placed on the stator lamination stack (14) at the axial ends (5, 7) and in that the grooves (8 ) within the stator lamination stack (14) have a uniform radial distance (rc) from the axis of rotation (4) both in the axial direction and around the axis of rotation (4).

6. Electrical machine according to one of the above claims, d a d u r c h e c e n e c i n e that the

Groove groups (12) each comprise more than one groove (8), in particular two, three or four grooves (8).

7. Electrical machine according to claim 6,

characterized in that Dieje ^¬ Nigen grooves (8) of a respective groove group (12) about the rotational axis (4) around not seen on a the jeweili ^¬ ge groove group (12) centrally dividing the first axial plane (17) lying radially inward a Groove opening (19), which seen around the rotation axis (4) around between the first axial plane (17) and a respective groove (8) centrally tei ^¬ lumbar second axial plane (18) is arranged.

8. Electrical machine according to one of the above claims, characterized in that in the case that the groove groups (12) each comprise an odd number of grooves (8), the central groove (8) of the respective Slot group has ^¬ (12) radially inwardly a groove opening (19) which is centrally arranged ^¬ respect to the corresponding groove (8).

9. Electrical machine according to claim 8,

That is, the groove bottom (10) of the central groove (8) has a nose (20) projecting radially inwards.

10. Electrical machine according to one of the above claims, characterized in that the stator (1) seen around the rotation axis (4) in those areas in which the grooves (8) are arranged, the groove bottoms (10) the smallest radial distance ( Having rl) of the rotational axis (4), in its radially outer region in the axial direction extending recesses (21, 22).

11. Electrical machine according to claim 10,

characterized in that mindes ^¬ least one of the recesses (21, 22) in cross-section transverse to the rotation axis (4) seen as a closed recess (22) is formed.

12. Electrical machine according to claim 11,

characterized in that the at least one closed recess (22) of the guide ei ^¬ Nes cooling medium is used.

13. Electrical machine according to claim 10, 11 or 12, characterized in that in min ^¬ least one of the recesses (21, 22) a communication cable (23) is arranged.

14. Electrical machine according to one of the above claims, characterized in that the windings (11) at both axial ends (5, 7) of the stator (1) each have a winding overhang (25) and that the winding overhangs (25) of the windings (11) do not intersect at the respective axial end (5, 7) of the stator (1).