DE10037787A1 - Permanent magnet excited synchronous machine e.g. general purpose drive motors, has external rotor design with external rotor joined rotationally-rigidly to rotatable shaft, around common axis - Google Patents

Abstract

A permanent magnet excited machine with external rotor design, has magnetic return cores (6) aligned axially on the inner periphery of the largely bell-shaped rotor wall (5) arranged uniformly around the periphery but not exclusively equi-distant. Permanent magnets (9) are arranged on its inner periphery and the magnetic return cores (6), when viewed radially inwards, are supported by one or more axially-spaced encircling carrier rings (7).

Description

The invention relates to a permanently excited synchronous machine according to the Transverse flow principle and in particular a special construction of the rotor in External rotor construction.

The invention relates to motors for general drive purposes, wherein in particular, a rotor diameter in the range of 40 mm to 400 mm is used shall be. However, the invention is not limited to these sizes; They are only given as an example for the drive task specified here.

Transversal flux machines are distinguished from other motors by a high torque density and moderate short-circuit currents. That's what they are excellent for direct drives in wheel hub applications therefore built with advantage as external rotor machines. This is also technological  Construction advantageous because the force application point is further outside than the same large inner rotor construction.

But since the magnetic flux in transverse flux machines is essentially axial to the air gap, the problem arises that the rotor is not, as in conventional machines, can be made from circular round sheets.

It is known to attribute the axial magnetic flux in the stator (also used in DE 196 14 862), whereby round plates are used in the rotor can, which with a suitable external support to a stable per se Build the active part of the rotor. However, this results in an active part geometry considerable scattering paths, which show the advantages of transverse flow technology completely annihilates.

The technology described here therefore uses an approximately axial flow guide in the rotor. The basic principle of such an arrangement has already been described in general by H. Weh (etzArchiv Vol. 10 ( 1988 ) pp. 143-149) and illustrated by the active part of an internal rotor machine; however, there is no mention of a mechanical construction which allows this machine to be built.

With the machine according to the invention, this principle is realized for the first time in a form that can be produced in a sensible manner:
The active part of the stator consists of phases arranged next to one another, each of which consists of an annular coil which is inserted into a groove which is formed by p-shaped U-shaped soft iron bodies which are distributed equidistantly on the circumference. These U cores are opposed to 2 p I-shaped soft iron parts on the rotor, which are provided with alternating polarized permanent magnets which excite an alternating flux in the U cores. This can be achieved either with sheets running parallel to the axis, in each case complementary polarized flat permanent magnets per phase, or by an inclination of the rotor and / or stator sheet by one pole pitch. The latter arrangement is mandatory if permanent magnets lying between the rotor yokes are used.

Because the relative position of the permanently excited field in the air gap to the teeth of the winding enclosing a phase, the phase position of the induced Voltage determined in the corresponding phase must be in a multi-phase Machine the mean angular position of the rotor magnets or the position of the stator teeth or both can be offset accordingly, which is indicated by a corresponding Bevel of the rotor or stator plates or by appropriate offset of the U- Cores or the I-cores or by a combination of these approaches can be achieved.

Basically, machines can be implemented with any number of phases; practically Two- and three-phase arrangements are particularly relevant. Is preferred Phase uses an annular coil in a slot; but it can also be a phase be distributed over several annular coils in several grooves and / or a groove be energized with coils from different phases. To use a machine to obtain largely electrically symmetrical phases, the phases be magnetically separated at least on the rotor or on the stator; Taking asymmetrical phases in purchase, so this separation can also be dispensed with become.

In the aforementioned DE 197 14 895, the rotor plates are designed as circular blanks, i. H., they are ring-shaped sheets which are layered perpendicular to the axis of rotation are trained.

The disadvantage of this solution, however, is that, according to the above Description, form significant scattering paths, which the maximum achievable Reduce engine torque significantly.

The invention is therefore based on the object of a transverse flux machine to design that a stable construction is achieved and at the same time scatter paths  are significantly minimized, so that a higher torque per volume can be generated.

To achieve the object, the invention is through the technical teaching of Claim 1 marked.

An essential feature of the invention is that on the inner circumference of a essentially bell-shaped rotor shell according to the principle evenly distributed around the circumference, but not necessarily exactly equidistant, in basically arranged in the axial direction yoke cores whose inner circumference permanent magnets are arranged, and that the Inference cores seen radially inward through one or more in the axial Direction spaced circumferential support rings are supported.

The solution shown here shows a rotor construction, which is its basic Gives strength through a tubular construction outside the active part in the the rod-shaped inferences made of soft iron material refer to additional rings support which in particular the radially inward force component take up.

These carrier rings can run outside the magnetic circuit of the phases (with magnetically separated phases, as in FIGS. 1 to 3 or with magnetically connected phases, as in FIGS. 4 and 5). Alternatively, carrier rings made of electrically poorly conductive material can be attached within the magnetic circuit ( FIGS. 6 to 8). The radial fixation of the soft iron parts can be realized by various methods, such as gluing, casting, injection molding and, if necessary, also by prefabricated form-fitting spacers.

A magnetic is preferably used as the material for the carrier rings used here non-conductive material used, such as. B. aluminum, aluminum alloys, Brass and other non-ferrous metal alloys as well as ceramics and ceramic Composites.  

In some applications, the carrier ring can also consist of iron material. Overall, the carrier ring can consist of a solid material or of laminated layered materials from the above Material selection.

According to the invention, the scatter paths are now due to this special conception minimized in that it is now possible for the first time to be aligned in the axial direction to use individual and separate yoke cores, which in the Rotor bell are arranged and by the carrier rings according to the invention are supported. There are here for the support structure according to the invention different versions, all of the inventive concept of the present Invention should be included.

In a first, preferred embodiment it is provided that in the axial Direction distributed several, running along the circumference of the rotor bell and in closed carrier rings are present, the carrier rings being the same Wear inference cores and the inference cores for their part on the underside Wear permanent magnets.

Here, the yoke cores are piecewise in the axial direction, i. H., they form interruptions between them seen in the axial direction, in their Area of the respective carrier ring is arranged.

With this construction, a yoke core is therefore on its front and Back (seen in the axial direction) carried by a support ring each.

In another, modified embodiment, however, it is provided that the inference cores are essentially over the entire axial length of the Extend rotor and have corresponding grooves in which the Carrier rings are arranged and thereby the yoke cores are worn.  

In a modified embodiment, it can be provided that the radial expansion of the groove in the respective yoke core for receiving the Carrier ring is minimized so that only the bottom of each Yoke core sits on the radially outer surface of the carrier ring.

In another embodiment, it can also be provided that the Recess for holding the support ring in a groove of the Permanent magnet itself is arranged.

In a further embodiment of the invention, the carrier ring is above the stator-side winding arranged in a gap between two in the axial Direction of permanent magnets, again the carrier ring can either be arranged in a groove of the yoke core and the height this groove can also receive the value 0 in the radial direction.

In a modification of this embodiment, it can be provided that the groove for Recording the carrier ring is not arranged in the yoke core, but in the permanent magnets arranged on the underside of the yoke core.

In a further embodiment it is provided that a plurality of In principle, rotor teeth evenly distributed on the inner circumference of the Rotor bell is arranged. Between the rotor cores are the radial Permanent magnets attached. In principle, these permanent magnets are in the In contrast to the previously mentioned embodiments, so to speak, edgewise oriented, and also in this construction, the rotor teeth with the intermediate permanent magnets by appropriate inventive Carrier rings worn.

In the following the invention is based on several ways of execution illustrative drawings explained in more detail. Here go from the drawings and their description further features and advantages of the invention.

Show it:

Figure 1 is a longitudinal section through a transverse flux machine showing the upper half.

Fig. 2 perspective side view in the position of a yoke core in the rotor with its holder;

FIG. 3 shows an exemplary embodiment modified compared to FIG. 2;

Fig. 4 is a second embodiment showing a longitudinal section through the upper half of a transverse flux machine with a continuous in the axial direction yoke core;

Fig. 5 shows the embodiment of Figure 4 showing the holder of a single yoke core.

FIG. 6 shows an exemplary embodiment modified compared to FIG. 4 with a centrally arranged carrier ring which is arranged directly opposite the winding on the stator side;

Fig. 7 is a perspective view of the embodiment of Fig. 6;

FIG. 8 shows a modification compared to FIG. 7;

Fig. 9 shows another embodiment of a transverse flux machine with permanent magnets lying between the inferences.

In Fig. 1 a half section of a transverse flux machine is shown generally, and with an external rotor 1 is non-rotatably connected to a shaft 2 which can rotate about an axis of rotation 3. There are one or more bearings 4 for the rotary mounting of the bell-shaped rotor 1 , which forms a rotor jacket 5 in the longitudinal direction.

According to the invention, yoke cores 6 a, b, c are now arranged one after the other in the axial direction on the inner circumference of the rotor jacket 5 , the holding of a single yoke core being shown in FIG. 2.

Each yoke core 6 consists essentially of a magnetically conductive material, which can be a laminated sheet material or a solid material.

It is now important that each yoke core 6 a- 6 c has a recess 15 on the end face, which is penetrated by a carrier ring 7 which is circumferential and self-contained. In the exemplary embodiment according to FIG. 1, a total of four such carrier rings 7 a- 7 b are arranged in the axial direction at a mutual distance from one another.

On the underside of the respective yoke core 6 , a permanent magnet 9 a, 9 b, 9 c is arranged here, which is connected to the yoke core 6 in a manner not shown.

The entire arrangement is preferably cast in, so that the yoke cores 6 , the associated support rings 7 carrying them and the permanent magnets 9 are enclosed in a plastic material.

Instead of pouring, it can also be provided that the carrier rings 7 are glued, welded, soldered, mechanically clipped or otherwise positively connected to this part in their recesses 15 , in the region of the yoke cores 6 .

In a manner known per se, an air gap 8 is formed between the stator 10 and the rotating rotor 1 .

In the exemplary embodiment shown, the stator consists of a stator core 11 , on the axial length of which there are a total of three windings 12 , 13 , 14 . Of course, more or fewer than three such windings 12-14 can also be provided.

The windings 12-14 are flowed through by alternating currents of different phase in motor operation.

It is important in the embodiment of FIGS. 1 and 2 that very high forces are exerted during the operation of the engine on the yoke cores 6 in the direction of arrow 16 , which act radially inward, and here these yoke cores 6 by the carrier rings 7 a according to the invention - worn 7 d.

The height 17 of the recesses 15 , in which the carrier rings 7 lie, is variable. This height 17 can go up to the vicinity of the outer circumference of the yoke core 6 ; however, the height 17 can also have the value 0, in which case the carrier ring would lie directly on the underside of the yoke core 6 according to the exemplary embodiment according to FIG. 1.

In Figs. 4 and 5 another embodiment is shown, where it can be seen that are not in the axial direction piecewise behind the other arranged yoke cores 6 exists, but it is in each case a single, continuous in the axial direction yoke core 20 is provided, where such yoke cores 20 the Principle according to uniform, but not necessarily equidistant, distributed over the circumference in the axial direction and are carried with the carrier rings 19 a, 19 b according to the invention.

In the yoke cores 20 here circumferential grooves 23 are incorporated, in which the carrier rings 19 a, 19 b are received. In the exemplary embodiment shown in FIG. 4, the carrier rings protrude with their lower edge over the lower edge of the respective yoke core 20 and are arranged approximately flush with the lower edge of the permanent magnets 21 a- 21 f arranged below. This is a preferred embodiment. However, the invention is not limited to this.

The same applies here as with regard to the height 17 of the recess 15 , namely that the height of the groove 23 (corresponding to the height 17 in FIG. 1) is variable, so that the groove 23 and the carrier rings can also be completely omitted in this exemplary embodiment 19 then rest with their radially outer surface on the underside of the yoke cores 20 .

The permanent magnets 21 a- 21 f each form recesses 22 between them, opposite which the respective winding 12-14 is arranged in the stator 10 .

The stator is in this case formed on a row of U-shaped stator cores 18-18 c arranged axially one behind the other, an associated permanent magnet 21 a- 21 b being associated with each U-leg of the respective stator core 18 a- 18 c.

Fig. 5 shows again the representation in Fig. 4 in a perspective side view, where it is also shown that the height 17 of the groove 23 can vary, so that the groove 23 can also be omitted and the surface of the carrier rings 19 then directly on the Bottom of the trailing edge 20 rests.

FIGS. 6 and 7 show a comparison with FIGS. 1 to 5 modified embodiment, which is characterized by a construction with centrally above the windings 12-14 arranged support rings 24.

There, the stator 10 is only shown with a single U-shaped stator core 18 , which carries a winding 12-14 . Such an arrangement can, however, also be repeated in the axial direction, as shown in FIGS. 1 to 4. It is essential there that the carrier ring 24 is arranged centrally in the yoke core 25 in the region of a groove 26 and that the stator-side winding 12-14 is arranged centrally opposite.

The permanent magnets 27 a, 27 b are then arranged laterally on the outside, opposite to the U-shaped legs of the stator core 18 .

This situation is shown again in FIG. 7 in a perspective side view, the same statements regarding the height 17 as for the other embodiments also apply to the groove 26 here.

FIG. 8 shows a further embodiment, which essentially corresponds to a combination of the embodiments in FIGS. 3 and 6.

It can be seen there that the permanent magnet 27 itself has a groove 26 , through which the carrier ring 24 extends, and thus the entire mounting takes place only through the groove 26 in the permanent magnet 27 for the yoke core 25 .

FIG. 9 shows a further exemplary embodiment, in which return cores are provided distributed around the circumference, of which only two return cores 28 a, 28 b are shown as examples. A distance 29 is provided between each yoke core 28 , which is filled by a permanent magnet 30 in each case. In this way, an alternating sequence of a yoke core 28 a, a permanent magnet 39 , a yoke core 28 b, another permanent magnet, etc. is provided on the circumference.

In this embodiment, it is essential that the permanent magnets 30 are arranged approximately upright in comparison to the previously described embodiments.

This example is only intended to show that even with such a rotor construction it is provided according to the invention that carrier rings 19 are present which carry the respective yoke cores 28 .

Here, in the vicinity of the end faces of the yoke cores 28 , mutually opposite grooves 31 are provided, each of which is penetrated by a carrier ring 19 .

Here too, the same statements apply as to the groove 31 , which extends through the respective yoke cores 28 , as was made with reference to the height 17 with respect to the recess 15 and the groove 23 .

It is essential in all embodiments that one in the circumferential direction closed support element in the form of a carrier ring is present, which is now is able to axially extending the circumferentially arranged Wear yoke cores and support against radially inward forces.

This makes it possible, for the first time, to use yoke cores that are present piece by piece use which compared to a construction with annular Inference plates significantly minimize the existing scatter paths result.  

drawing Legend

2

rotor

3

wave

4

axis of rotation

5

camp

6

rotor casing

7

Yoke core (rotor a, b, c)

8th

Carrier ring a, b, c, d

9

air gap

10

Permanent magnet a, b, c

11

stator

12

stator core

13

winding

14

winding

15

winding

16

recess

17

arrow

20

18

Height of the recess

15

19

Stator core a, b, c

20

Carrier ring a, b

21

Yoke core

22

Permanent magnet af

25

23

recess

24

groove

25

support ring

26

Yoke core

27

groove

28

Permanent magnet a, b

29

Yoke core

28

a, b

30

distance

31

permanent magnet

32

groove

Claims (16)

1. Permanently excited synchronous machine in external rotor design, comprising an external rotor ( 1 ), which is rotatably connected to a shaft ( 2 ) rotatable about an axis ( 3 ) and one between a rotor shell ( 5 ) of the rotor ( 1 ) and the shaft ( 2 ) arranged stator ( 10 ), the rotor ( 1 ) and stator ( 2 ) forming a cylindrical tubular gap ( 8 ) between them, characterized in that the inner circumference of the essentially bell-shaped rotor shell ( 5 ) is distributed in principle evenly over the circumference, but not necessarily equidistant, yoke cores ( 6 ; 20 ; 25 ; 28 ) are arranged aligned in the axial direction, on the inner circumference of which permanent magnets ( 9 ; 21 ; 27 ; 30 ) are arranged and that the yoke cores ( 6 ; 20 ; 25 ; 28 ) seen radially inwards are supported by one or more circumferential carrier rings ( 7 ; 19 ; 24 ; 24 ) spaced apart in the axial direction. 2. Permanently excited synchronous machine according to claim 1, characterized in that the carrier rings ( 7 ) outside the magnetic circuit of the windings ( 12-14 ). 3. Permanently excited synchronous machine according to claim 2, characterized in that the stator cores ( 18 ) of the windings ( 12-14 ) are separated from one another and thus the windings ( 12-14 ) are essentially magnetically decoupled from one another. 4. Permanently excited synchronous machine according to claim 2, characterized in that the stator cores ( 11 ) of the windings ( 12-14 ) are connected to one another and thus the windings ( 12-14 ) are essentially magnetically coupled to one another. 5. Permanently excited synchronous machine according to claim 1, characterized in that the carrier rings ( 7 ) run within the magnetic circuit of the windings ( 12-14 ) and are formed from electrically poorly conductive material. 6. Permanently excited synchronous machine according to one of claims 1 to 5, characterized in that the permanent magnets ( 9 ; 21 ; 27 ; 30 ) are carried by the yoke cores ( 6 ; 20 ; 25 ; 28 ). 7. Permanently excited synchronous machine according to claim 6, characterized in that the permanent magnets ( 9 ; 21 ; 27 ) are attached in an approximately radial direction on the underside of the yoke cores ( 6 ; 20 ; 25 ). 8. Permanently excited synchronous machine according to claim 6, characterized in that the permanent magnets ( 30 ) are each mounted between the yoke cores ( 28 a, 28 b). 9. Permanently excited synchronous machine according to one of claims 1 to 8, characterized in that the yoke cores ( 6 ; 28 ) are supported at their axial ends by a respective carrier ring ( 7 ; 19 ). 10. Permanently excited synchronous machine according to claim 9, characterized in that carrier rings ( 7 ; 19 ) engage in recesses ( 15 ) of the yoke cores ( 6 ; 28 ). 11. Permanently excited synchronous machine according to one of claims 1 to 8, characterized in that the yoke cores ( 20 ; 25 ) extend substantially over the entire axial length of the rotor ( 1 ). 12. Permanently excited synchronous machine according to claim 11, characterized in that the yoke cores ( 20 ; 25 ) have corresponding grooves ( 23 ; 26 ) in which the carrier rings ( 19 ; 24 ) are arranged. 13. Permanently excited synchronous machine according to claim 11, characterized in that the yoke cores ( 20 ) rest with their radial undersides on the radially outer surface of the carrier rings ( 19 ). 14. Permanently excited synchronous machine according to claim 11, characterized in that the carrier rings ( 24 ) lie in grooves ( 26 ) of the permanent magnets ( 27 ) and thus the yoke cores ( 25 ) are supported. 15. Permanently excited synchronous machine according to one of claims 1 to 14, characterized in that the carrier rings ( 7 ; 19 ; 24 ) are arranged radially outside the stator-side windings ( 12-14 ). 16. Permanently excited synchronous machine according to one of claims 1 to 15, characterized in that the carrier rings ( 7 ; 19 ; 24 ) are arranged in a gap between two axially spaced apart permanent magnets ( 9 ; 21 ; 30 ).