WO2011003718A2

WO2011003718A2 - Stator and method for producing a stator

Info

Publication number: WO2011003718A2
Application number: PCT/EP2010/058581
Authority: WO
Inventors: Gerhard Riepl
Original assignee: Gerhard Riepl
Priority date: 2009-07-07
Filing date: 2010-06-17
Publication date: 2011-01-13
Also published as: EP2556580A2; DE202009009304U1; WO2011003718A3

Abstract

The invention relates to a stator (5), in particular for an electric motor (1) that is implemented in at least two parts and comprising a flux ring (7) and a plurality of bars (9) connected to the flux ring (7) for receiving windings (11). The stator (5) is characterized in that at least some of the bars (9) are made at least partially of a grain-oriented material.

Description

STATOR AND METHOD FOR PRODUCING A STATOR

description

The invention relates to a stator, in particular for an electric motor according to the preamble of claim 1, an electric motor according to the preamble of claim 10 and a method for producing a stator according to the

The preamble of claim 11.

Electric motors and electric generators of the type discussed here have a stator and a rotor arranged coaxially therewith. In operation of a

Electric motor or a generator, the rotor rotates relative to the fixed stator. The relative movement between the two engine components is usually effected by magnets arranged on the rotor and electromagnets cooperating therewith and provided on the stator.

In this case, the stator can be provided in the interior of the rotor for realizing an external rotor motor, while the rotor is arranged in the interior of the stator for realizing an internal rotor motor. For small vehicles, such as scooters or wheelchairs, often external rotor motors are used, the rotor also serves as a rim for a wheel of the small vehicle.

In order to reduce the material consumption in the production of stators and to be able to use simpler winding techniques for the production of electromagnets, it is known to form the stator of an electric motor or a generator at least in two parts. Multi-part stators are known, for example, from the publications DE 295 22 169 Ul, GB 2 423 421 A and from CH 261 739. Such stators have a yoke ring and several with the

Return ring connected webs, wherein the webs for the formation of

Electromagnets are wrapped in a wire. Due to the separate production of the return ring and the webs of the stator, the material consumption in the Production can be significantly reduced. In addition, a simpler winding technique for generating the electromagnets can be applied in this way.

Electric motors of the type mentioned here can, as already mentioned

indicated, for example, as traction drives in wheelchairs and scooters in rehabilitation are used. Also known is their use in battery-powered vehicles, such as golf caddies, bicycles, vans or floor cleaning machines. Other applications are printing machines,

Cutting machines, packaging machines, pump drives, agitators, winding drives, textile machines, pharmaceutical and medical electrically operated devices, gate drives, drives for conveyor technology, wind generators, etc ..

In particular, when using electric motors in wheelchairs or scooters overcoming obstacles, such as overcoming curbs or similar surveys is problematic because this often lacks the necessary peak power of the electric drive. A higher peak power is usually possible only by a larger design of the electric motor, which in turn leads to an increase in weight, an increased space requirement and higher production costs.

Object of the present invention is therefore to provide a stator, in particular for an electric motor for use in a wheelchair or similar vehicles, which has a high peak performance and at the same time can be made compact and which is also inexpensive to produce.

The above object is achieved by a stator with the features of

Patent claim 1 solved. It is at least in two parts and has a yoke ring and a plurality of webs connected to the yoke ring, which are provided for receiving windings. The stator is characterized in that at least some, preferably all webs at least partially consist of a grain-oriented material. This means that at least some of the webs consist of a grain-oriented material. It must therefore not necessarily be formed all ridges of a grain-oriented material. It is also conceivable, for example, to produce only every second or third web of a grain-oriented material.

However, it is particularly advantageous if all the webs are made entirely of a grain-oriented material. In principle, it is also conceivable to construct at least one, preferably all webs in several parts, in particular two parts, wherein only a part of the multi-part web can consist of a grain-oriented material.

The invention is based on the finding that the peak power of an electric motor or of an electric generator depends inter alia on the magnitude of the magnetic flux which is generated in the electromagnet of the stator. As already explained, the electromagnets of the stator are formed by the webs provided with windings.

The magnetic flux in the webs, which for example by a

alternating electrical current in the webs surrounding windings is created, should be as large as possible to achieve a power maximization of the electric motor. However, alternating electrical fields result in a permanent re-magnetization of the webs, resulting in the re-magnetization losses that cause the

reduce magnetic flux and therefore are to be minimized.

By the use of a grain-oriented material is the

Correction loss in the webs during operation of the electric motor substantially reduced, since the magnetic flux is concentrated and amplified in the webs. The material has a uniform grain structure, i. the grains are the same orientation with respect to the orientation of their crystal axes unlike a non-oriented material.

By the same orientation of the grains, the magnetization of the webs is positively influenced, in particular, a grain-oriented material has a lower Ummagnetisierungswiderstand compared to a non-grain-oriented material. A grain-oriented material, in particular a grain-oriented steel, also called electrical steel, can be produced for example by a thermal treatment.

The following example shows that re-magnetization losses can be substantially reduced by the use of grain-oriented material: If the loss of magnetization when using non-grain-oriented material for the webs is, for example, 1.4 W / kg, for webs it is made of a grain-oriented material and otherwise the same General conditions only approx. 0.73 W / kg. As a result, it is advantageously possible to reduce the cross section of a web with a constant magnetic flux.

Between two adjacent lands then a larger volume is present, which is advantageously used to increase the number of turns or to use a thicker winding wire, which in turn has a higher

can generate magnetic flux. With a suitable combination of a

Bar cross section reduction and a larger volume can be achieved by the

Using a thicker winding wire up to 54% higher drive power can be achieved with otherwise constant size of the electric motor or the generator.

It is understood that the stator proposed here can be used for both DC motors and AC motors. The proposed stator can also be used for electric motors or generators of various types

Performance classes are used. The invention is therefore not on a

certain type of electric motor or generator type.

Particularly preferably, the grain orientation runs essentially in the longitudinal direction of the webs. The material used is preferably electrical steel, but the use of another suitable grain-oriented material is also conceivable. The stator proposed here is preferably intended for use with an external rotor motor, but in principle it can also be used for the realization of an internal rotor motor. In addition, the stator according to the invention may also be provided for use with a generator.

The web can be formed in two parts, moreover. In this case, a web has a web body and a web head, wherein the web body consists of the grain-oriented material and the web head can either consist of a grain-oriented material or of a magnetic powder, of a magnetic powder mixture or of any other suitable material.

In the latter case, the web consists only partially of a grain-oriented material. Furthermore, the return ring preferably consists of a non-grain-oriented material. However, it is also conceivable that the yoke ring is formed segment-like and the individual segments are made of a grain-oriented material.

To achieve the above object is also according to claim 9

Use of a stator according to the invention for an external rotor motor, an internal rotor motor or proposed for a generator.

To achieve the above object, moreover, an electric motor with the features of claim 10 will propose, in particular an external rotor motor having a stator according to the invention.

Finally, a method for producing a stator with the features of claim 11, in particular for an electric motor is proposed to solve the above object, wherein the stator is formed at least in two parts and has a yoke ring and a plurality of webs. The method is characterized in that at least some, preferably all webs are at least partially made of a grain-oriented material. This means that at least some of the webs are made of a grain-oriented material. It must therefore not necessarily be formed all ridges of a grain-oriented material. It is also conceivable, for example, to produce only every second or third web of a grain-oriented material. In principle, it is conceivable to construct at least one, preferably all webs in several parts, in particular two parts, wherein only a part of the multi-part web can consist of a grain-oriented material. Regarding the benefits of

Inventive method is referenced to avoid repetition of the above advantages of the stator.

The webs are preferably punched or lasered from the grain-oriented material. By packaging material layers, in particular of electric sheets, the stator is brought to the desired stator length. It is preferably provided that the webs are punched or lasered such that the grain orientation of the material used extends substantially in a longitudinal direction of the webs.

The invention will be explained in more detail below with reference to the drawing. FIG. 1 is a sectional view of an electric motor according to the invention; FIG.

Fig. 2 is a schematic side view of a stator according to the invention;

Fig. 3 is a schematic representation of a two-part web formed;

4 shows a schematic illustration of a two-part web in the assembled state;

5 is a plan view of a web head.

Fig. 6 is a schematic representation of several interconnected

Footbridges, and Fig. 7 is a schematic representation of a plurality of interconnected

Steg bodies.

Fig. 1 shows an electric motor 1, which is purely exemplified as an external rotor motor and serves as a drive for a wheelchair or the like. The electric motor 1 has a rotor 3 and a stator 5. The stator 5 is formed in several parts and comprises a yoke ring 7, which is connected to a plurality of webs 9, which are preferably pressed into the yoke ring 7. The webs 9 are formed by laminated cores and are each provided with windings 11 for the realization of electromagnets. The number of windings and the thickness of the wire used may vary depending on the application. Furthermore, the windings 11 can be protected as complete windings and insulated applied directly to the webs 9. Also conceivable is the use of air coils or the use of coils on bobbins.

The outer peripheral surface u of the rotor 3 is exemplified in the figure 1 as a rim, and on the inner peripheral surface i of the rotor 3 magnets 13 are applied, preferably glued. Furthermore, the rotor 3 with a

A-end shield 15 and connected to a B-bearing plate 17, in particular screwed, wherein the A-bearing plate 15 and the B-bearing plate 17 are arranged substantially symmetrically to a plane A, which is perpendicular to a rotational axis D of the electric motor 1. The rotor 3 is also supported with two ball bearings 19 and 21 and on the hub 23 from.

The yoke ring 7 is arranged on a closed housing 25 of an electromagnetic brake 27. The solenoid brake 27 is formed here without a mechanical manual release. The housing 25 of the solenoid brake 27 is connected by screws 29 to the hub 23 and has a two-sided brake disc 31st

Incidentally, the hub 23 serves to receive the electric motor 1 on a shaft of the vehicle. The power supply of the electric motor 1 and the power supply and actuation of the solenoid brake 27 via a multi-core Supply cable 33, which in turn with a not shown here

electronic control device is connected.

Electric motors of the type discussed here are often described in the prior art, so that their operation is not discussed in more detail.

FIG. 2 shows the stator 5 according to FIG. 1 in a schematic side view. The same parts are provided with the same reference numerals, so that in so far on the

Description is referenced to Fig. 1.

The stator 5 has, as already stated above, arranged on the housing 25 of the solenoid brake 27 return yoke ring 7 and a plurality of webs 9 connected thereto. For receiving the webs 9, the yoke ring 7 in its peripheral surface 35 a plurality of recesses 37, in which projections 38 of the respective webs 9 are to be arranged. Preferably, the projections 38 of the webs 9 are pressed into the recesses 37. It is understood that the webs 9 may be connected in other ways with the yoke ring.

In Fig. 2, the peripheral surface 35 of the yoke ring 7 is not completely provided with recesses 37 to simplify the illustration. In addition, only three integrally formed webs 9 are shown in corresponding recesses 37 of the yoke ring 7. It is understood that the recesses 37

usually evenly distributed over the entire peripheral surface 35 of the

Return yoke 7 are provided and each recess 37 has an associated web 9. Depending on the power requirement of the electric motor, however, the number of recesses 37 and the associated webs 9 may vary.

The three webs 9 are arranged side by side as shown in FIG. 2 and have a defined distance from each other in a radially outer region.

According to the invention, some, preferably all webs 9 are made of a grain-oriented material, in particular of electric sheet or dynamo sheet with a certain thickness. The grain orientation of the material used In this case, the tool in the production of the webs 9 must be aligned relative to the material so that the longitudinal axis L of the webs to be produced points in the direction of the grain orientation. For this purpose, the direction of grain orientation of the material used must be known. The grain orientation of the webs 9 is indicated in FIG. 2 by arrows 39.

An integrally formed yoke ring 7, as shown in FIG. 2, can indeed be produced from a grain-oriented material, but the grain orientation then does not run continuously in a radial direction r of the yoke ring, as would be desirable. For the yoke ring 7 is therefore preferably a non-grain-oriented material, in particular an electrical sheet or

Dynamo plate used. The non - grain orientation of the material of the

Return yoke 7 is indicated in Fig. 2 by pointing in different directions arrows 41. It is clear that, in contrast to the grain-oriented material, the orientation of the crystal axes of a non-grain-oriented material is not ordered.

However, it is also conceivable to subdivide the return ring 7 into a plurality of segments (not shown) of suitable size and to then manufacture the individual segments from a grain-oriented material, in particular from electrical steel. In the preparation is to ensure that the grain orientation of the material in a radial direction r of the segments of the yoke ring 7 extends. The individual segments can then in a suitable manner to a yoke ring. 7

be joined together.

In Fig. 3 is an imple mentation shape of a web 9 is shown, which is formed in two parts. The two-part web 9 comprises a web body 43 and a

Bridge head 45. Both components of the web 9 can be made of a grain-oriented material. However, it is also conceivable to produce only the web body 43 from a grain-oriented material and the web head 45 from a magnetic powder or from a magnetic powder mixture. The latter embodiment additionally improves the magnetic conduction of the webs 9. The web body 43 and the web head 45 can be connected to each other in a suitable manner, for example, glued or pressed together. For this purpose, the web body 43 preferably has a projection 47 and the web head 45 to a complementary opening 49 formed.

In Fig. 4, the two-part web 9 is shown in an assembled state. It is clear that the projection 47 engages in the opening 49.

Fig. 5 shows a plan view of the web head 45 according to FIGS. 3 and 4. The same parts are provided with the same reference numerals, so that in so far on the

Description is made to the previous figures.

5, the opening 49 which extends in a longitudinal direction of the web head 45 and serves to receive the projection 47 of the web body 43 is particularly well recognizable. In addition, it is clear that Figs. 3 and 4 are sectional views along the section line A-A of Fig. 5 represent. The length of the opening 49 and the length of the web head 45 depend on the required length of the stator core.

In Fig. 6 and Fig. 7, a plurality of interconnected webs 9 and web body 43 are shown, which are made of a grain-oriented material in one piece from the band, in particular punched or laser cut and packaged in one piece. Each two adjacent webs 9 are for this purpose by a thin

Material web 51 connected.

The number of interconnected webs 9 and the length of the material webs 51 can be adapted in this way exactly to the circumference of the yoke ring 7 and the number of recesses 37 provided. The length of the individual material webs 51 may be corresponding to the distance between

adjacent recesses 37 are adapted. Thus, it is possible to connect the webs 9 in one piece with the yoke ring 7 and the material webs 51 - if necessary - to remove after connection with the yoke ring 7. Several webs 9 can be summarized in the rest to a "web package" of the same polarity. The webs 9 of a "web package" are preferably connected to each other, for example by means of the material webs 51. However, it is also conceivable for a connection of the web heads 45, which can also be made in one piece.

The webs 9 may be integrally formed, as shown in Fig. 6. In this case, the windings 11 before connecting the webs 9 with the

Return ring 7 are applied by means of a suitable winding technique on the webs 9.

The webs 9 may also be formed in two parts, as shown in Fig. 7. In this case, it is possible to first only manufacture the web body 43 and connect it to the yoke ring 7 and only then to provide the web body 43 with windings 11. Subsequently, the web heads 45 can then be connected to the web bodies 43.

In a method according to the invention, some, preferably all webs 9 are at least partially made of a grain-oriented material, wherein the webs are preferably processed by means of conventional methods, in particular punched or lasered, that the grain orientation of the material in the

L longitudinal direction L of the webs 9 extends. This results in a substantially lower loss of core magnetization than is the case with the use of non-grain-oriented standard electrical metal sheets for the webs 9.

Due to the lower loss of core loss, the cross section of the webs 9 can be substantially reduced, so that the distance a between the webs 9, as shown for example in Fig. 6, is greater. This also causes the existing volume between the webs 9. This in turn causes a winding wire of larger diameter for generating electromagnets can be wound around the webs 9. The web body 45 can be arranged close together with a small distance, because the webs 9 are individually with

Windings provided so that it is not necessary to introduce the winding wire through the narrow distances between the web bodies 45. The thicker winding wire can then be up to 54% higher output power can be achieved. Furthermore, it is preferably provided that only after the winding of the webs or the web packages of the web head 45 is connected to the web body 43, in particular glued.

As already mentioned, the size and configuration of all components of an electric motor or a generator according to the invention can vary depending on the application. This applies in particular to the length of the stator, the circumference of the stator

Return ring 7 and the number and design of the webs 9. It is crucial that the stator has at least two components, namely a

Return ring and a "web ring", which consists of a plurality of individual and / or interconnected webs, wherein the webs are at least partially made of a grain-oriented material.

The choice of grain-oriented material, in particular its quality, may vary depending on the application. Preferably, however, stamped individual sheets, in particular dynamo sheets, also called electrical sheet or transformer sheet, are used to produce the webs, which generally sheet metal material of an iron-silicon alloy with soft magnetic properties

designated. The sheet is described in the standard "grain-oriented electrical steel sheet and strip in final annealed condition" (DIN EN 10107: 2005-10).

Overall, it is found that the present invention advantageously combines a multi-part design of the stator 5 with the use of a grain-oriented material for the webs 9 of the stator 5. In this way, an electric motor or a generator can be created, which has a greater power than a conventional electric motor of comparable size and which is also inexpensive to produce.

The invention is not limited to the use of the stator for an external rotor motor. Rather, the stator according to the invention can readily be used for an internal rotor motor. In this case, the stator is then appropriate designed differently, in particular, the "web ring" is then arranged radially inwardly with respect to the yoke ring.

LIST OF REFERENCE NUMBERS

1 electric motor

3 rotor

5 stator

7 return ring

9 footbridge

1 1 windings

13 magnets

15 A-bearing plate

17 B-end shield

19 ball bearings

21 ball bearings

23 hub

25 housing

27 Electromagnetic brake

29 screws

31 brake disc

33 supply cable

35 peripheral surface

37 recess

38 advantage

39 arrow

41 arrow

43 web body

45 bar head

47 advantage

49 opening

51 material web

u outer peripheral surface

i inner peripheral surface

A level

D rotation axis

L longitudinal direction

r radial direction

a distance

Claims

claims

1. Stator (5), in particular for an electric motor (1) which is formed at least in two parts and a yoke ring (7) and several with the

Return ring (7) has connected webs (9), which are intended to receive windings (11),

characterized,

that at least some of the webs (9) at least partially from a

grain-oriented material.

2. Stator according to claim 1,

characterized,

that the grain orientation extends substantially in the longitudinal direction (L) of the webs (9).

3. Stator according to claim 1 or 2,

characterized,

in that the grain-oriented material is electrical steel.

4. Stator according to one of the preceding claims,

characterized,

that the webs (9) are formed in two parts.

5. Stator according to claim 4,

characterized,

in that the webs (9) have a web head (45) which consists of a magnetic powder or of a magnetic powder mixture.

6. Stator according to one of the preceding claims,

characterized,

that the yoke ring (7) consists of a non-grain-oriented material.

7. Stator according to one of the preceding claims,

characterized,

that the yoke ring (7) is segmented.

8. stator according to claim 7,

characterized,

that the individual segments of the yoke ring (7) are made of a grain-oriented material.

9. Use of a stator according to one of claims 1 to 8 for a

External rotor motor, for an internal rotor motor or for a generator.

10. Electric motor (1), in particular external rotor motor, with a stator

and a rotor,

characterized,

in that it comprises a stator (4) according to one of claims 1 to 8.

11. A method for producing a stator (5), in particular for an electric motor (1), wherein the stator (5) is formed at least in two parts and a

Return yoke ring (7) and a plurality of webs (9) connected to the yoke ring (7), which are intended to receive windings (11),

characterized,

that at least some of the webs (9) at least partially from a

grain-oriented material can be produced.

12. The method according to claim 11,

characterized,

in that the webs (9) are made of the grain-oriented material such that the grain orientation extends in a longitudinal direction (L) of the webs (9).

13. The method according to claim 11 or 12,

characterized,

that the stator (5) is brought to the desired stator length by packing electrical steel sheets.

14. The method according to any one of claims 11 to 13,

characterized,

in that the windings (11) are applied to the respective webs (9) before connecting the webs (9) to the return ring (7).