WO2009098172A2

WO2009098172A2 - Electric machine excited by permanent magnets for driving a component of a domestic appliance, bank comprising electric machines of this type excited by permanent magnets and domestic appliance comprising a machine of this type

Info

Publication number: WO2009098172A2
Application number: PCT/EP2009/051090
Authority: WO
Inventors: Michal Kalavsky; Falk Laube; Jörg SKRIPPEK
Original assignee: BSH Bosch und Siemens Hausgeräte GmbH
Priority date: 2008-02-05
Filing date: 2009-01-30
Publication date: 2009-08-13
Also published as: WO2009098172A3; DE102008007565A1

Abstract

The invention relates to a machine excited by permanent magnets, to a bank comprising electric machines of this type excited by permanent magnets, each machine being designed to drive a component of a domestic appliance and having a rotor and a stator. According to the invention, the rotor and/or the stator has or have a plurality of stacked and interconnected plate-type sheet metal parts (1, 7) and at least each rotor and/or stator can be constructed in a modular manner depending on the number of sheet metal parts (1, 7) in order to achieve a modular construction for the machine.

Description

Permanent magnet excited electric machine for driving a

Component of a household appliance, set comprising such permanent magnet excited electrical machines and household appliance with such a machine

The invention relates to a permanent magnet excited electric machine for driving a component of a domestic appliance, a set of such machines, each having a rotor and a stator, wherein the rotor and / or the stator has a plurality of stacked and interconnected plate-like sheet metal parts.

An electric machine for driving a component of a household appliance, having a rotor and a stator, the rotor and / or the stator having a plurality of stacked and interconnected plate-like sheet-metal parts, is apparent from WO 2005/060074 A1.

Electric machines, in particular in the form of electric motors are known in many embodiments. In this regard, BLDC motors, which are brushless DC drives, are also known. Due to the structure of such engines they are only for specific purposes specific to conceptualize, which is relatively expensive and expensive. It must therefore be provided a variety of different concepts, each with different components. In addition, relatively large engines of this type are very noisy.

It is an object of the present invention to design a permanent magnet excited electrical machine in terms of their variable design and dimensioning easier and to operate noiselessly with regard to their use in a home appliance. Accordingly, a corresponding sentence of the type defined above should be specified. It is also intended to indicate a corresponding permanent magnet-excited electric machine and a corresponding domestic appliance. This object is achieved by a set having the features of the corresponding independent claim. In addition, the object is also achieved by a permanent-magnet-excited electric machine and a household appliance, which each have the features of the corresponding independent patent claims.

A set according to the invention comprises permanent magnet-excited electrical machines which are each designed to drive a component of a domestic appliance. Each electric machine comprises a rotor and a stator. The rotor and / or the stator have a plurality of stacked and interconnected plate-like sheet metal parts. For the modular construction of each machine of the set, at least the rotor and / or the stator can be modularly constructed depending on the number of sheet metal parts.

Thus, a concept is made possible for a set of electrical machines which can be modularly assembled and dimensioned with regard to their requirements. This is done by constructing the rotor or the stator or the rotor and the stator of each machine each of a plurality of identical parts, namely plate-like sheet metal parts which are stacked in the axial direction. The high flexibility with regard to the dimensioning and design of one of these components can be made possible by the variably selectable number of sheet metal parts, which can then be stacked easily and with little effort and can be joined together.

This allows a cross-device and / or cross-platform module system, whereby the use of as many identical components can be guaranteed. By means of such a modular principle in the sense of the modular principle, the production of various types of equipment on a production line can be made possible, whereby an increase in the number of units and a reduction in costs can be achieved.

Preferably, the stator of each machine of the set according to the invention is formed of a plurality of stacked in the axial direction of the stator sheet metal parts and the sheet metal parts have an outer dimension less than or equal to 100 mm. It can be provided that the plate-like sheet metal parts of the stator are circular, so that the outer dimension defines an outer diameter. However, it can also be provided that the sheet metal parts are angularly shaped and, for example, have an approximately quadrangular geometry in which the edge lengths are less than 100 mm. By such a compact and relatively small dimensioned design of the stator noise reduction can still be achieved with the same functionality. Such small external dimensions or sheet diameter lead when using such a machine in the household appliance, such as a tumble dryer or a washing machine, to significantly reduced noise emission and significantly lower noise excitation.

The ratio of the external dimension to the axial length of the stator is particularly optimized to avoid the excitation of natural frequencies over the entire speed range of each machine, which can be particularly advantageous by the small dimensions with external dimensions less than or equal to 100 mm. Also, by the specific design with the sheet metal part stacking and the specific geometry and shape of the sheet metal parts, this can be favorably influenced.

Preferably, at least one further identical part is used for the modular construction of each machine of the set according to the invention, regardless of the intended number of sheet metal parts for the modular construction of the rotor and / or the stator. In particular, the common part is a bearing plate of the electric machine, whereby nevertheless the same bearing plate can be used with different design and dimensioning of a rotor and / or a stator. Also, the modular principle can be favored favorably and a simplified conceptual design can be made possible.

In particular, the bearing plate is made of die-cast aluminum.

In particular, a seal, in particular an elastomer seal, is arranged between a bearing plate and a component formed by stacked sheet-metal parts, in particular in the rotor and in the stator. This seal can also be a common part for all machines in the sentence according to the invention. In conjunction with an aluminum die-cast end shield, the noise behavior can thus be further improved. The use of closed aluminum die-cast end shields sealed to the laminated core thus also makes it possible to produce a highly functional assembly, which designed noise and cost optimized. Is. In addition, this embodiment also provides protection of the magnets in the rotor against environmental influences, such as pollution, metal chips or corrosion. In addition, the seal between the bearing plate and one of the components mentioned above simultaneously serves to damp vibrations.

Preferably, a fan is arranged on the shaft of each electric machine of the set according to the invention. The fan can be designed as a radial fan or as an axial fan and used for cooling by the heat generated during operation of the machine is dissipated. In this context, this particular arrangement of the fan is achieved in each case particularly advantageous that the heat generated in the winding of the stator is guided in the direction of the bearing plate to the outside. This is a particularly advantageous heat dissipation.

Preferably, in each machine of the set according to the invention, a sheet metal part of a rotor is circular, and in the region of the recess for insertion of a

Permanent magnet is formed a smaller radius than the radius formed by the entire circumferential radius of the rotor. The outer contour of the sheet metal part of the rotor thus has different curvatures at specific regions.

As a result, the operating principle can be improved. It has proven to be particularly advantageous if the radius is continuously reduced in the specific area and / or in the area adjacent to the specific area.

As a result, a sinusoidal air gap geometry can be achieved between rotor and stator. Thus, disturbing noises can be further reduced because the tonal component of the number of poles corresponding to the one-and-many times the harmonic frequency is reduced.

Preferably, in each machine of the set according to the invention, a sheet metal part of a stator is circular and has radially oriented teeth which are straight at their side facing the center. In particular, the teeth are T-shaped. It is particularly preferred if each permanent-magnet-excited electric machine of the set according to the invention is designed as a BLDC motor. In particular, such a brushless DC motor can be operated with three-phase current.

The design as a BLDC motor, a particularly favorable ratio between efficiency improvement, noise minimization and modular design or modular principle can be achieved.

The noise-optimized design can be made possible in particular by the optimized air gap geometry (rotor and stator lamination) and compact design (advantageous ratio between length and outer dimensions of said components) in each machine of the set according to the invention. Due to the BLDC concept in combination with an optimized sheet metal part geometry of rotor and / or stator and a specific winding design a particularly favorable efficiency can be achieved.

The object is also achieved by a permanent-magnet-excited electric machine, which in particular has the advantageous features of a machine selected by the inventive set of permanent magnet-excited electric machines. Advantageous developments are also given by the advantageous developments of the sentence, wherein the features in the invention can be applied individually or in any combination. Conversely, advantageous developments of the machine can also be included in the set of permanent magnet-excited machines according to the invention.

Preferably, the machine comprises a rotor and a stator, wherein the rotor and / or the stator comprises a plurality of stacked and interconnected plate-like sheet metal parts. By using stacked and interconnected sheet metal parts, preferably at least the rotor and / or the stator can be modularly constructed depending on the number of sheet metal parts.

In particular, it is of advantage if the machine for reducing the noise between a bearing plate encompassed by the machine and a component formed by stacked sheet metal parts, a seal, in particular an elastomeric seal, is arranged or the machine has a noise-optimized air gap between the stator and rotor, for example by the sheet metal part of the rotor is substantially circular and in the region of a recess for inserting a permanent magnet has a smaller radius compared to the total radius of the sheet metal part.

An inventive household appliance is designed in particular for the care of laundry items and includes a machine from the inventive set of permanent magnet electrical machines or an advantageous embodiment thereof.

The household appliance according to the invention, in particular for the care of laundry items, thus comprises a machine comprising a set comprising permanent magnet electrical machines each for driving a component of a household appliance, each with a rotor and a stator, wherein the rotor and / or the stator stacked a plurality of having interconnected plate-like sheet metal parts, wherein in each case for the modular structure of the machine, at least the rotor and / or the stator is modular depending on the number of sheet metal parts.

Especially when using such a machine from the set according to the invention in a domestic appliance, the drive of components can be carried out particularly efficiently and quietly. Since home appliances are usually located in living rooms, this can be achieved a significant improvement in user-friendliness. Last but not least, the compact design of the machine of the set and its modular design make it possible to provide a highly flexible variable system which can be made available to a wide variety of household appliance types.

Preferably, the domestic appliance has a drum for receiving items of laundry, which can be driven by such a permanent-magnet-excited electrical machine, in particular a BLDC motor. An embodiment of the invention is explained in more detail below with reference to schematic drawings of an example of an electric machine from a set according to the invention of such machines. Show it:

Figure 1 is a schematic plan view of an inserted for a stator of the electric machine sheet metal part.

Fig. 2 is an enlarged view of a partial section of Fig. 1;

FIG. 3 is a schematic plan view of a sheet metal part used for a rotor of the electric machine; FIG.

4 shows an enlarged detail of the illustration according to FIG. 3;

5 shows a schematic representation of a rotor assembly of the electrical machine; and

Fig. 6 is a schematic representation of the electrical machine.

In the figures, identical or functionally identical elements are provided with the same reference numerals.

As shown in FIGS. 5 and 6, a rotor 27 and a stator 31 are provided in a permanent magnet excited electric machine 30, particularly in a BLDC motor. The electric machine 30 is arranged in a tumble dryer or a washer-dryer or a washing machine and provided for driving, for example, a drum of the domestic appliance. In this case, the rotor 27 is arranged on a shaft 24. In addition to the rotor 27, a fan 21 is provided, Further, on the shaft 24, an A-side bearing 22, an encoder 23, a B-side bearing 25 and a pinion 26 are arranged for a belt transmission. Such an arrangement may be preassembled as a rotor assembly 20.

6 shows the electrical machine 30, which comprises the rotor assembly 20, wherein the rotor assembly 20 A-side bearings 22 in the A-side end shield 32 and the B- side bearing 25 is mounted in the B-side end plate 35. Between the end shields 32 and 35, the stator 31 is arranged. The A-side end plate 32 has a bulge 33, which is designed to receive a device for speed detection. This device introduced in the bulge acts together with the rotary encoder device 23 arranged on the shaft 24.

The electrical machines 30 of the set presented here are each highly flexible with regard to their conceptual composition and can be individually assembled according to a modular principle and dimensioned with regard to their operating parameters, in which respect a multiplicity of identical parts can be used. In this context, for example, the bearing plate 32 and / or 35, which is preferably made of die-cast aluminum, be used for a variety of different dimensions of the electric machine 30. In this connection, each electric machine 30 of the set may be modularly constructed such that the stator 31 is constructed of a plurality of stacked and interconnected plate-like sheet metal parts 1.

In this context, an embodiment of one of these sheet metal parts 1 is shown in Fig. 1, which is circular in this regard. The sheet metal part 1 has, for example, a thickness (extension perpendicular to the plane of the figure) of about 0.5 mm. This value is merely exemplary and may be otherwise constructed.

In the axial direction (in the direction perpendicular to the plane of the figure) a plurality of such identically formed sheet-metal parts 1 are stacked, and these firmly connected to one another, for example glued or welded. Characterized the stator 31 is formed, wherein depending on the number of the same shaped sheet metal parts 1, the dimensioning can be specified, and depending on the number of sheet metal parts 1 and the modular structure of the stator 31 can be performed individually. From the number and thickness of the sheet metal parts 1 results in the length L_s of the stator 31st

In the exemplary embodiment, the stator 31 is designed with a designed as an internal rotor 27, wherein the stator 31 and thus each of the sheet metal parts 1 in the radial direction oriented teeth 2, some of which are designated in more detail in Fig. 1. The Teeth 2 are formed in the direction of rotation equidistant to each other and arranged and designed T-shaped. Each tooth 2 of the sheet metal blank or sheet metal part 1 has a tooth root 3 and a tooth head 4. To the tooth root 3, the windings are wound when the desired number of sheet metal parts 1 is stacked. The tooth tips 4 are arranged at a distance r from the center M in a radius r1. In the free space 6 formed thereby, the rotor is rotatably arranged.

In Fig. 2 is an enlarged view of a partial section of the sheet metal part 1 shown in FIG. 1 is shown. In this it can be seen that the center of the M facing front tooth edge 5 of the tooth head 4 is straight and thus forms a plane in three-dimensional view of the plate-like sheet metal part 1. This tooth flank 5 thus has no curvature adapted to the radius r1.

In Fig. 3, an embodiment of a sheet metal part 7 is shown in a plan view. The rotor 27 of the electric machine 30 is formed by a plurality of axially stacked sheet metal parts 7, wherein also here the modular structure is dependent on the selected number of these sheet metal parts 7. The length L_r of the rotor 27 results from the number and thickness of the sheet-metal parts 7. In the exemplary embodiment, both the stator 31 and the rotor 27 are modularly constructed and dimensioned depending on the number of stacked sheet-metal parts 1 and 7 used in each case , Depending on this, at least one operating parameter of the electric machine 30 can thus be predefined accordingly.

Again, there is a stacking of the sheet metal parts 7 in the axial direction and thus in the direction perpendicular to the plane of the figure.

A sheet-metal part 7 comprises in the direction of rotation a plurality of identically dimensioned and identically shaped recesses 8 into which, after the joining of the plurality of sheet-metal parts 7 and thus the formation of a stack of sheets, the permanent magnets are inserted and adhesively bonded, for example. By the incorporation of the magnets in the recesses 8, these are arranged as buried magnets.

The sheet metal parts 7 are disc-like or circular. In Fig. 4 is an enlarged partial section I of the illustration in Fig. 3 is shown. It can be seen that in the region 9 of the sheet metal part 7 in which the recess 8 is formed, the outer contour 10 has a radius r3 which is different from the basic radius r2 of the entire sheet metal part 7. The radius r3 is smaller than the radius r2, so that in the area 9, the outer contour 10 has a greater inward curvature than is formed by the entire circumferential unit radius r2. The radius r2 is drawn around the center M, which corresponds to the center of the sheet metal part 7 and in the entire assembled state of the electric machine 30 and the center M of the stator 31 as shown in FIG. In contrast, the radius r3 is spaced from the center M drawn around the point N.

In the regions 14A and 14B, which each adjoin the region 9, the radius r3 of the outer contour 10 of the rotor 7 is further reduced continuously. The outer contour 10 thus results in the areas 14A, 9 and 14B an approximately sinusoidal course. In an alternative embodiment, the outer contour can also be continuously reduced in the region 9, so that the sinusoidal profile of the outer contour 10 can be further approximated to a sinusoidal shape.

Between the end plate 35 and 32 and a formed laminated core of the stator 31, an elastomeric seal 36 is arranged in each case. In addition, a radial fan 21 or an axial fan is positioned on the shaft 24 of the BLDC motor 30.

The outer dimension d of the sheet metal part 1 of the stator 31 according to FIG. 1 is less than 100 mm. In the exemplary embodiment, this means that the outer diameter d (FIG. 1) is less than 100 mm.

In Fig. 1, the outer diameter d of the sheet metal part 1 of the stator is about 92 mm. The projections of the welds 1 1, 12 and 13 are not counted in this respect to the sheet metal part 1 and thus not used for the dimensioning of the outer diameter d.

The same applies to an embodiment of the electric machine 30 shown in FIG. 6 with an angular, for example quadrangular, shape of the sheet-metal part 1, in which case a corresponding edge length is less than or equal to 100 mm.

Claims

claims

1. Set comprising permanent magnet-excited electrical machines (30), each for driving a component of a household appliance, each with a rotor and a stator, wherein the rotor and / or the stator comprises a plurality of stacked and interconnected plate-like sheet metal parts (1, 7) characterized in that each of the modular structure of the machine, at least the rotor and / or the stator depending on the number of sheet metal parts (1, 7) is modular buildable.

2. Set according to claim 1, wherein in each machine (30) of the stator (31) of a plurality of in the axial direction of the stator (31) stacked sheet metal parts (1) is formed and the sheet metal parts (1) an external dimension (d) less than or equal to 100 mm.

3. Set according to one of claims 1 and 2, wherein in each machine (30) for modular construction of the machine (30) at least one further identical part regardless of the respectively provided number of sheet metal parts (1, 7) for modular construction of the rotor (30). 27) and / or the stator (31) is inserted.

4. Set according to claim 3, wherein in each machine (30) has a bearing plate (32, 35) is used as a common part for modular construction of the machine (30).

5. Set according to claim 4, wherein in each machine, the bearing plate (32, 35) is formed of die-cast aluminum.

6. Set according to one of the preceding claims, wherein in each machine between a bearing plate and a stacked sheet metal parts (1, 7) formed component, a seal, in particular an elastomeric seal, is arranged.

A kit according to any preceding claim, wherein a fan (21) is disposed on each shaft (24) of each machine (30).

8. Set according to one of the preceding claims, wherein in each machine, a sheet metal part (7) of a rotor is circular and in the region (9) of the recess (8) for inserting a permanent magnet in comparison to

Total radius (r2) of the sheet metal part (7) smaller radius (r3) has.

9. A set according to one of the preceding claims, wherein in each machine (30), a sheet metal part (1) of a stator (31) is circular and radially oriented teeth (2), which at its the midpoint (M) side facing

(5) are straight.

A kit according to any one of the preceding claims, wherein each machine (30) is a BLDC motor.

1 1. A permanent magnet excited electric machine (30) for driving a component of a household appliance, each having a rotor (27) and a stator (31), wherein the rotor (27) and / or the stator (31) a plurality of stacked and with each other connected plate-like sheet metal parts (1, 7), characterized in that between a bearing plate (32, 35) and a stacked by sheet metal parts (1, 7) formed component a seal (36), in particular an elastomeric seal, is arranged.

12. Permanent magnet excited electric machine (30) for driving a component of a household appliance, each with a rotor (27) and a stator

(31), wherein the rotor (27) and / or the stator (31) comprises a plurality of stacked and interconnected plate-like sheet metal parts (1, 7), characterized in that the sheet metal part (7) of a rotor (27) substantially is formed circular and in the region (9) of a recess (8) for inserting a permanent magnet in comparison to the total radius (r2) of the

Sheet metal part (7) smaller radius (r3) has.

13. A permanent magnet excited electric machine (30) according to claim 12, wherein the radius (r3) of the outer contour (10) of the sheet metal part (7) towards an outer edge of the region (9) of the recess (8) for inserting a permanent magnet and / / or an area (9) adjacent region (14A, 14B) steadily decreases.

14. Permanent magnet excited electric machine (30) according to claim 13, wherein the outer contour (10) of the sheet metal part (7) in the region (9, 14A, 14B) of the recess (8) for insertion of a permanent magnet has a substantially sinusoidal course.

15. Domestic appliance, in particular for the care of items of laundry, which for driving a component of the domestic appliance comprises a machine according to one of claims 11 to 14 or a selected from a set according to one of claims 1 to 13 machine.

16. Domestic appliance according to claim 15, which has a drum for receiving items of laundry, which is drivable by means of the machine (30).