DE102013101084A1 - Rotary field machine with external rotor, in particular in modular design - Google Patents

Abstract

The invention relates to an induction machine with a housing in which at least one stator, a rotor, in particular external rotor and a shaft are arranged. According to the invention, at least one support part (2, 4) is provided, on which the stator and at least one bearing (10, 12) are arranged and on the housing (6) a receptacle (24) for electronics.

Description

Rotary field machine with external rotor, in particular in modular design.

The invention relates to a rotating field machine with external rotor, according to the preamble of claim 1.

State of the art

Generic induction machines are used as electric motors or electric generators and have a fixed stator and a rotatably mounted rotor. The demands on the performance, dynamics and controllability of such engines are constantly increasing. In addition, the drive electronics are increasingly being combined with the motor, in particular at high powers in low-voltage applications, in order to increase the power density and to reduce the contacting effort.

• a) Stator des Außenläufermotors kann nur schwer bewickelt werden,
• b) Außenläufermotoren haben in der Regel ein thermisches Problem, da Wärme primär im Innenbereich des Motors entsteht(im bewickelten Stator) und kann daher schlecht abgeführt werden (langer Wärmepfad)
• c) Rotoren von Außenläufermotoren sind nur einseitig gelagert und daher durch die Fliehkraftbelastung in der Länge begrenzt, während Innenläufermotoren in der Länge beliebig skaliert werden können.

External rotor motors have the physical advantage over internal rotor motors in that the force of the induction machine is generated outdoors. They are therefore characterized in comparison to internal rotor motors in that they have a high force or torque density. A disadvantage of an external rotor, that the rotating part is accessible from the outside and therefore requires an additional housing, which protects the rotating part. This can reduce the benefits of power density again with an inappropriate overall design. Therefore, external rotor motors are primarily used in the application as fan drives, in which the rotating rotor is the core of a fan. The housing can be realized much easier with an internal rotor motor. In addition, external rotor motors have the following disadvantages:

• a) stator of the external rotor motor can be wound only with difficulty
• b) External rotor motors usually have a thermal problem, since heat is generated primarily in the interior of the motor (in the wound stator) and can therefore be dissipated poorly (long heat path)
• c) rotors of external rotor motors are mounted only on one side and therefore limited by the centrifugal load in the length, while internal rotor motors in the length can be scaled arbitrarily.

In the WO 2011/113522 A3 is a brushless external rotor motor with integrated electronics in the above-mentioned embodiment shown as a fan drive. The rotor of the motor is connected to a fan wheel, the electronics are integrated with the stator of the electric motor. Thus, a compact unit can be built. The disadvantage of such a construction is that the rotor is open and can be attracted to the rotor via the air flow and the attractive force of the magnets, in particular when permanent magnets are used in the rotor, and thus can block the air gap between the stator and rotor. This can lead to a failure of the engine and is not allowed, especially for traction drives for safety reasons.

In the EP 2179488 B1 An advantageous stator structure of an external rotor motor is shown by the applicant, which makes it possible to achieve a high degree of copper filling with a standard winding technique. This is achieved in that the stator is designed as a strip and can be bent flexibly and thus when winding the stator, for example, with a needle winder the space between the stator teeth can be almost completely filled with copper. This problem is solved a).

In the not pre-published DE 10 2011 111 667.6 the Applicant, the outer rotor is developed so that the excitation coils of the inner stator are sealed with a material having high thermal conductivity and spaced at a small distance from the stator. Thus, the heat generated in the stator can be dissipated well. The rotor is made of plastic and has inlaid magnets and an inserted laminated core. By inserting the laminated core, the losses in the rotor can be reduced, whereby the rotor has low temperatures and thus can be made of plastic. By casting with a material with good thermal conductivity and the small distance of the coils to the flange, the heat can be dissipated well. This disadvantage b) of the external rotor motor is eliminated.

In the US 7683515 B2 the inventor an external rotor motor with two stators (inner and outer stator) is shown with double air gap between the rotor and both stators. The rotor is made of a ferromagnetic material and is thin-walled and magnets are attached to the inside. The magnetic flux generated by one or more wound stator radially penetrates the rotor completely and closes over the second stator, separated on the other side of the rotor over an air gap. Such motors have a low inertial mass and are suitable for highly dynamic drives. Due to the thinness of the rotors, the rotor has limited structural load capacity.

Object of the invention

The invention is based on the object, a cost-effective induction machine for a Application as a traction drive in the low voltage range (<60V) for a wide power range of 4-18 kW to generate high power and high torque with a compact design and low weight.

The task could be solved well in the high voltage range with a length-scaled internal rotor motor. In the low voltage range, however, the power is limited by the voltage, the resistance of the coils, the permanent magnet flux and the inductance. In addition, it must be avoided that the inductance becomes too small, so that the demand on the switching frequencies of the power electronics increases too much to avoid cost increases in electronics and electronic switching losses. In addition, a good field weakenability is desirable to increase the speed at low torque. For a good field weakenability, a higher inductance is advantageous. Since low inductance associated with a low number of turns, also the winding technique is very complex, since thick wires must be used in low-induction machines. The power scaling can be from o.g. For physical reasons, therefore, only by an increase in diameter, which excludes the use of a sheet metal section.

An internal rotor motor is from o.g. Therefore reasons for a low-voltage drive up to 20kW with the restriction of the maximum permissible outside diameter can not be represented, since a length scaling would lead to very low inductances. Even a separately excited synchronous machine does not use the advantage of field weakenability via high inductances, since the inductance in the low-voltage range is physically very low. Even with other types of motors (eg pancake), the power spread of 4-20 kW can only be represented with different laminations.

Inventive task solution

The object of the invention is achieved with the features of claim 1.

With the solution according to the invention a cost-effective induction machine for use as a traction drive in the low voltage range (<60V) for a wide power range of 4-18 kW is created, with a high performance and high torque is achieved in a compact design and low weight.

The other claims contain advantageous embodiments or developments of the invention.

Since the external rotor motor has a lower active length than an internal rotor motor, the inductance is higher and the power and torque requirement can be covered according to the invention by one or two coupled rotors with a Statorstanzblechschnitt.

The motor is advantageously modular and characterized in particular in that it consists of one or two stator / flange assemblies and a housing part takes over the function of the electronics and motor housing and air cooling by ribbing. Advantageously, the possibility of electrical parallel connection of the excitation coils of the stator modules by separate punched grid and connections to the electronics, which contributes to the inductance and power increase. Stator with punched grid and flange is an assembly in which the coils are positioned at a small distance from the radially erstckenden part of the flange and with a material with good heat conduction properties in particular (resins with material admixed with thermally conductive elements such as boron / nitride) potted or im Duroplastherstellverfahren is encapsulated.

The rotor of the motor consists of a preferably deep-drawn rotor base carrier, which at one end radially outwardly formed and U-shaped (axial extent in two directions with two cylindrical surfaces with a bottom wall) and additionally preferably radially stepped. Inserted in the rotor are laminated cores and segmented magnets, which are still encapsulated as needed. The rotor is therefore particularly very stiff and resilient with very high radial forces and also has very low iron losses. By a combination of two rotor base carriers, these are positively locked, e.g. by welding, screwing or riveting, converted into a double-T-beam structure or H-structure. Thus, both rotors are additionally stiffened by the connections, as they can support each other and the motor can be scaled in length in addition to a one-sided rotor of an external rotor motor.

The contacting takes place in the flange region of the stator flange assembly, where a stamped grid is arranged, preferably via a screw connection with a circuit board of the power electronics. The power electronics have a modular design, ie with the double rotor design ( 1 ) two modules are used, with the single rotor only one module. The power electronics has a separate power and control part, wherein the power unit is advantageously divided into two modules. This motor can be equipped with single rotor and double rotor with the same equipped motherboard of the power unit.

• – Leistungsskalierung über einen sehr breiten Bereich mit einem Blechschnitt;
• – Nutzung des hohen Wirkungsgrad und der Drehmomentdichte von Außenläufermotoren;
• – Wirkungsgradsteigung durch Rotoraufbau mit integriertem Blechmagnet und gestückelten Rotoren;
• – Sehr steife Rotorstruktur insbesondere bei hohen Belastungen und Drehzahlen;
• – Sehr gutes Kurzschlussverhalten durch hohe Induktivität und redundante Kontaktierung;
• – Gute Feldschwächbarkeit durch hohe Induktivität, somit Reduzierung der Phasenströme in der Leistungselektronik;
• – Ein kombiniertes Gehäuseteil für Motor- und Leistungselektronik;
• – Redundanz des Antriebes durch redundante Kontaktierung (2 Stromkreise);
• – Gute Wärmeabfuhr durch Verguss mit Material mit geringer Wärmeleitfähigkeit und direkter Kontakt Spule mit Flanschteil;
• – Gute Wärmeaufteilung durch räumlich getrennten Wärmeeintrag und Positionierung Elektronik in Mittenbereich des Gehäuses bzw. im Elektronikdeckel;
• – Kostengünstiger Aufbau durch Verwendung von Gleichteilen (Rotorbaugruppen) und Werkzeugen;
• – Einfache Montage;
• – Modularer Aufbau sowohl von Motor als auch Leistungselektronik;
• – Sehr hohe Belastbarkeit durch radiale Kräfte durch großen Lagerabstand.

With the invention or its advantageous embodiments, in particular the following (further) features and advantages arise

• - Power scaling over a very wide range with a sheet cut;
• - Utilization of high efficiency and torque density of external rotor motors;
• - Increase in efficiency due to rotor design with integrated sheet metal magnet and fragmented rotors;
• - Very stiff rotor structure, especially at high loads and speeds;
• - Very good short-circuit behavior due to high inductance and redundant contacting;
• - Good field weakenability due to high inductance, thus reducing the phase currents in the power electronics;
• - A combined housing part for engine and power electronics;
• - Redundancy of the drive due to redundant contacting (2 circuits);
• - Good heat dissipation by casting with material with low thermal conductivity and direct contact coil with flange;
• - Good heat distribution through spatially separated heat input and positioning electronics in the center of the housing or in the electronics cover;
• - Cost-effective construction through the use of common parts (rotor assemblies) and tools;
• - Easy installation;
• Modular construction of both motor and power electronics;
• - Very high load capacity due to radial forces due to large bearing clearance.

figure description

Embodiments of the invention and their advantageous embodiments are illustrated in the figures and described in more detail below.

Show it:

1 a longitudinal section (only the upper half) shown) by a first embodiment of a rotating field machine with double stator or double rotor;

2 a longitudinal section (only the upper half) shown) by a second embodiment of a rotating field machine with simple stator or rotor;

2a a detailed view of a runner support part.

In 1 is an embodiment of a rotating field machine according to the invention with an external rotor with two flange-stator assemblies and a double rotor in the H-structure or double-T-carrier structure shown. The illustrated rotary field machine has a first (left) stator carrier part 2 and a second (right) stator support member 4 on, which are opposite to each other in a substantially cylindrical housing 6 , which is in particular made in one piece, are arranged. In bores of Statorträgerteile is a continuous motor shaft 8th arranged. These are outside of the stator supports 2 respectively. 4 in corresponding recesses bearing 10 . 12 provided, in particular ball bearings for direct transmission of high radial forces. Camps 10 . 12 are arranged far outboard in the axial direction, so that there is a high load capacity due to radial forces. The stator carrier 4 . 10 have flange-like, radially extending, stepped sections 2a . 4a of which at least one may be provided with cooling fins, one of which is shown and with 4b is designated.

On the stator supports 2 . 4 , which are made of a material with good thermal conductivity and low weight (eg aluminum, magnesium) sit stator laminations 1 . 3 with their excitation coils 14 . 16 on insulation bodies 14a and 16a , The stator lamination packages are on the stator carrier 2 . 4 pressed or shrunk. The excitation coils 14 and 16 stand or end at a short distance to the radially outwardly projecting part 2a . 4a the stator-carrier and are with the stator lamination 1 . 3 and cast the stator with a material having high thermal conductivity 42 (For example, epoxy resin with boron nitride filler) or injection-molded with this. As a result, the heat of the stators can be well dissipated because the heat path is shortened, at the same time the heat is well divided on both sides of the engine.

As stated in the above DE 10 2011 111 667.6 the Applicant is described or illustrated may be provided in one embodiment of the invention, that the potting compound, with which the excitation coils are encapsulated or encapsulated, up to the stator, in particular its radial extent, reaching and with this over a larger area in connection are. With this measure, the heat transfer in the axial direction in the stator and over this over the housing to the outside significantly improved over the prior art, in which the coil ends are arranged relatively far away from the stator. This is further supported by the lead frame supporting the ends of the coil wires or pins is radially offset to the outside, so that space is created in the radially inner region and the contact area can be further increased and additionally, by a potting material with high thermal conductivity is used. The stamped grid enclosed by the potting compound is via contact pins or alternatively Contact straps connected to the electronics or the circuit board and sealed in the region of the stator by encapsulation to the electronics. It is also possible, as in DE 10 2011 111 667.6 disclosed to operate in the engine with oil cooling. Sufficient is already an oil mist, it improves the cooling between the rotor 18 . 19 and housing 6 because the heat is next to the cooling above the flange parts 2 and 4 can also be removed radially via the air to the housing. The heat dissipation is supported by internal air circulation, which by the fan elements in the rotor in the range 18a . 19 is stimulated. This results in a very even heat dissipation to the housing and a further increase in performance.

Between the stator laminations 1 . 3 remains a narrow passage in which a radial section 18a . 19a the rotor carrier parts 18 . 19 runs. The rotor carrier parts 18 . 19 sit non-rotatably on a central holding section 8a . 9a the motor shaft 8th , On both sides are stamped grid 15a . 15b and motor connections 17a . 17b intended for power output stage. The connections from or to these parts are guided through corresponding openings or passages in the housing. The punched grid 15a . 15b are arranged radially outboard between the rotor and housing to make room for the end parts of the coil or the potting.

The rotor carrier parts 18 and 19 are each U-shaped in longitudinal section, have a bottom wall 18a . 19a , and two cylindrical axially extending walls or sections 18b . 19b and 18c . 19c on. In the end region, the carrier parts are radially outwardly deformed 18d . 19d and in the middle area 18e and 19e optionally stepped inwards. By this design, the support structure is very resilient, especially for radial forces due to high speeds and magnetic forces. As a material for the support parts, a ferromagnetic material is advantageously used and selected as a manufacturing process a thermoforming process.

The rotor carrier parts are in the radial section 18a . 19a arranged adjacent to each other and connected together in this area. In addition, in this area 18a . 19a not shown fan elements are attached. In a simple embodiment, this can also axial holes through the rotor carrier parts 18 . 19 be. In addition, axial channels through the stator can 2 and 4 be designed so that the air is sucked in on one end face and out of the engine on the other front side. These channels can also be deflected radially, so that the air in the engine is circulated through the rotor area. In the axially extending leg of the carrier parts are laminated cores 21a . 21b arranged, which can be suitably designed as a revolving metal tube. The laminated cores or sheet metal tubes extend axially over the length of the carrier parts. Inside of this laminated core or sheet metal tube are broken permanent magnets 20a . 20b attached and connected to the metal tube in particular by means of suitable adhesive. The individual magnetic elements are each arranged in a row axially one behind the other, wherein a plurality of such rows are distributed over the circumference of the rotor with gaps. The magnets are glued to the laminated cores or sheet metal tubes on the surface or inserted into the sheet metal tube. The laminated cores are shrunk into the rotor carrier parts and pressed. Alternatively or additionally, the laminated core or sheet metal tube and the magnets can be arranged or inserted in accordance with a tool in the manufacture of the rotor and, if necessary, be encapsulated with plastic together with the fan elements described above. The encapsulation is in particular two-sided, so that the magnets and rotor on the inside / outside are protected against corrosion. Furthermore, in the axial region of the rotor rotor parts, if necessary, the injection-molded ribbing in addition to the radial deformation of the rotor carrier parts further reinforce the rotor and the radial deformation of the rotor in the end region 18d . 19d replace or supplement.

The housing 6 has in a region of its circumference radially projecting side walls, of which the cut shown in the drawing with 22a respectively. 22b are designated. Further side walls are provided at the front and at the back, so that at the periphery of the housing 6 a box-shaped housing section or recording 24 for receiving electronics is formed by a lid 26 sealed is completed. On the underside of the motor, the radially outwardly projecting side wall is made shorter, sufficient so that the flange portions of the stator 2a and 4a can be connected to the housing. The housing 6 is suitably made by Alugussverfahren, preferably also the stator 2 and 4 ,

Inside the electronics housing section 24 is on from the housing 6 formed protrusions or sockets 28a . 28b a first circuit board 30 arranged, which is used here in particular for the power electronics. This printed circuit board can be divided into two printed circuit boards, the two printed circuit boards are in the range 30a either mechanically separated or separated in a form that the assembly of the circuit boards is identical left and right and with each circuit board, the current is controlled by a stator. This division makes sense, in particular in terms of the modular design, so that for the construction with a stator (see execution 2 ) the same power board can be used. A second circuit board 32 is in a recess of the lid 26 arranged and used here for the control electronics. Power electronics and Control electronics can also be reversed in the arrangement. When arranging the power electronics on the cover, the motor connections 17a and 17b to be adjusted accordingly with the engine. In or around the recess may advantageously be provided cooling fins. Corresponding plug connections 34 respectively. 36 for the power or control electronics are shown only schematically and can, for. B. also be arranged axially opposite one another.

In addition, a sensor target 33 attached to the shaft and is connected via a sensor PCB 35 scanned with preferably Hall element. An oppositely arranged sensor circuit board is via a cable 37 via a passage in the flange or radial part 2a the carrier part 2 with the lower circuit board 30 connected. Alternatively, the cable can also be led to the upper circuit board and contacted.

For mounting, a stator-flange assembly including a connected rotor and a bearing is preferably first inserted into the housing, in a second step is the 2 , Stator flange assembly introduced and ultimately the 2 , Bearing and the seal 41 assembled. flange 2a and 4a then, for example, about screws 9 with the housing 28 connected. For this purpose, recesses are formed in the housing on both sides, can be used sealed in the end portions of the radially extending stator support members.

2 shows an embodiment in which only a stator support and according to only a bell-shaped rotor support member is provided. Here, on the one hand (right in the drawing), the bearing for the shaft in a flange-like end part 40 which is designed here without axially extending support member for the coil arranged. Incidentally, the structure essentially corresponds to that of the 1 ,

2a shows a detailed view of the rotor, wherein along at least a portion of the radially extending portions a rib 7 or the like extends to further stiffen the rotor in this area. This stiffening can in particular gem. 2 be expedient in which only a runner support member is provided.

Like in the DE 10 2011 111 667.6 the Applicant (to which reference is also hereby made), the external rotor in the invention may also consist of plastic, in particular thermosetting plastic and replace the U-shaped rotor carrier parts completely or partially. In a partial replacement, a large part of the U-shaped rotor support structure is replaced by plastic and if necessary reinforcing parts still inserted. In the plastic variant is in the axially extending leg of the outer rotor is radially outboard a laminated core arranged that can be conveniently designed as a revolving metal tube. The laminated core or sheet metal tube extends axially over the length of the rotor. Inside this laminated core or sheet metal tube segmented magnets can be attached and connected to the metal tube in particular by means of suitable adhesive. The individual magnetic elements are each arranged axially one behind the other in a row, wherein a plurality of such rows are distributed over the circumference of the rotor with gaps. The laminated core or sheet-metal tube and the magnets are arranged or inserted in accordance with a tool in the manufacture of the rotor and, optionally together with the fan elements described above, encapsulated in plastic. The encapsulation is especially on both sides, so that the magnets are protected on the inside against corrosion. Furthermore, if necessary, ribbing is integrated in the axial area, which reduces the centrifugal force load.

LIST OF REFERENCE NUMBERS

1

stator lamination

2

Stator support part

2a

radial portion of Statorträgerteils

3

stator lamination

4

Stator support part

4a

radial portion of the stator support member

4b

cooling fin

6

casing

7

stiffening

8th

motor shaft

8a

holding section

9

screw

10

camp

12

camp

14

Kitchen sink

14a

bobbins

15a

lead frame

15b

lead frame

16

Kitchen sink

16a

bobbins

17a

motor connection

17b

motor connection

18

Runner carrier part

19

Runner carrier part

18a

radial section

19a

Rotor support member

19b

Rotor support member

20a

 permanent magnets

20b

permanent magnets

21a

 laminated core

21b

laminated core

22a

Side wall

22b

 Side wall

24

housing section

26

cover

28a

base

28b

base

30

circuit board

30a

 Separation area between 2 printed circuit boards

32

circuit board

33

sensor target

34

connector

35

Sensor circuit board

36

connector

37

electric wire

39

passage

40

final part

41

poetry

42

grouting

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• WO 2011/113522 A3 [0005]
• EP 2179488 B1 [0006]
• DE 102011111667 [0007, 0027, 0027, 0037]
• US 7683515 B2 [0008]

Claims (16)

Rotary field machine with a housing, in which at least one stator, a rotor, in particular external rotor rotor and a shaft are arranged, characterized in that at least one stator carrier part ( 2 . 4 ) is provided, on which a stator ( 1 . 3 ) with excitation coils ( 14 . 16 ) and on the stator carrier part ( 2 . 4 ) at least one warehouse ( 10 . 12 ) and that on the housing ( 6 ) a recording ( 24 ) is provided for electronics. Rotary field machine in particular according to claim 1, characterized in that the stator carrier part ( 2 . 4 ), Stator ( 1 . 3 ) and exciting coil ( 14 . 16 ) form an assembly for a frontal mounting of the stator carrier parts. Rotary field machine according to one of claims 1 or 2, characterized in that the receptacle ( 24 ) is integrally formed for electronics with the housing. Rotary field machine according to one of the preceding claims, characterized in that on or in the housing ( 6 ) Cooling fins ( 4b ) are provided. Rotary field machine according to one of the preceding claims, characterized in that two carrier parts ( 2 . 4 ) are provided, on each of which a warehouse ( 10 . 12 ) is arranged. Rotary field machine according to one of the preceding claims, characterized in that the at least one carrier part ( 2 . 4 ) has a radially extending portion which closes the substantially tubular housing laterally. Rotary field machine according to one of the preceding claims, characterized in that the housing by means of substantially radially extending, in particular integrally formed with the housing wall sections, a receptacle ( 24 ), are housed in the electronic elements or assemblies and the like. Rotary field machine according to claim 7, characterized in that the receptacle ( 24 ) by means of a lid ( 26 ) is tightly closed. Rotary field machine according to claim 8, characterized in that in or on the cover ( 26 ) Electronic components or assemblies are arranged. Rotary field machine according to one of the preceding claims, characterized in that the rotor comprises a bell-shaped carrier (1) made of ferromagnetic material ( 18 . 19 ), which has a bottom wall and one or two cylindrical walls and is bent radially outwardly in the end region Rotary field machine according to claim 10, characterized in that two rotor carrier ( 18 . 19 ) are provided, the radially extending portions ( 18a . 19a ) are arranged at least partially adjacent to each other or supporting. Rotary field machine according to one of the preceding claims, characterized in that the coil ( 14 . 16 ) is at least partially potted or overmolded with the carrier part with a material having good thermal conductivity properties. Rotary field machine according to one of the preceding claims, characterized in that at least one ventilation device is provided in the interior of the housing or the receptacle. Rotary machine according to one of the preceding claims, characterized in that the rotor comprises a carrier part made of plastic. Rotary field machine according to one of the preceding claims, characterized in that the electronics has separate power and control areas. Rotary field machine, in particular according to one of the preceding claims, characterized in that the machine has a modular construction, in particular of the motor part and / or the electronics.

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