DE102019128714A1 - External rotor motor with a waveguide winding - Google Patents

Abstract

The invention relates to an electrical machine (1) in the form of an external rotor with: an internal stator (2), an external rotor (3) which surrounds the stator, and a motor housing (5). The electrical machine (1) according to the invention further comprises several coils (16) designed as waveguides, which form the winding of the electrical machine (1) and are each part of a cooling circuit of the electrical machine (1), the coils (16) having a hollow interior through which a coolant is pumped, and at least one coolant pump (13) for pumping the coolant through the coils (16), the coolant pump (13) being arranged in a space within the motor housing (5).

Description

The invention relates to an electrical machine in the form of an external rotor with an internal stator, an external rotor that rotates around the stator, and several coils designed as waveguides for generating a magnetic field, the coils each being part of a cooling circuit of the electrical machine are.

BACKGROUND OF THE INVENTION

Various designs of electrical machines with a waveguide winding are known from the prior art. The coils of such machines consist of tubular elements with a continuous channel through which a coolant flows in order to cool the winding during operation. The waveguide winding is usually arranged in the stator of the electrical machine, since in this case there is no hydraulic transition between moving and stationary parts in the coolant circuit. The sealing of the coolant circuit can thus be made much easier.

From the DE 10 2014 201 305 A1 For example, an electric motor is known which has a stator with a plurality of waveguide coils, each of which has a fluid inlet and a fluid outlet with corresponding connections. The waveguide coils arranged in the stator are connected to a distribution or collecting channel through which the coolant is supplied or discharged. A similar cooling concept for cooling a stator is also from the DE 10 2013 205 418 A1 known. In the electric motor disclosed there, the individual waveguide coils are also connected to a cooling circuit via a common distribution or collecting channel.

An external rotor is a rotating electrical machine in which the stator is located inside the electrical machine and is surrounded by the rotor (armature) on the outside. Due to their special design, it is difficult to cool external rotors because the stator is surrounded by the rotating rotor. The coolant can therefore only be fed with difficulty from the outside to the stator.

OBJECT OF THE INVENTION

It is therefore an object of the present invention to create an external rotor with a waveguide winding that is particularly compact and simple in construction.

This object is achieved according to the invention by the features mentioned in independent claim 1. Further embodiments of the invention emerge from the subclaims.

According to the invention, an external rotor is proposed which, in a known manner, has an internal stator, an external rotor which surrounds the stator, and a motor housing. The stator of the external rotor also has at least one coil designed as a waveguide, which forms the winding of the electrical machine and is part of a cooling circuit of the electrical machine, the coil (s) having a hollow interior through which a coolant is pumped. According to the invention, at least one coolant pump is provided which pumps the coolant through the coil or coils. The coolant pump is arranged in a space within the motor housing, preferably within the rotor. Because the pump (s) is / are integrated in the electrical machine, the electrical machine can be built in a particularly simple and compact manner.

The coolant pump is preferably coupled to the motor shaft and is driven by this. An additional drive for the coolant pump is therefore not required. A transmission can be provided between the motor shaft and the coolant pump.

According to a special embodiment of the invention, the motor housing comprises at least one coolant channel through which the coolant heated by the coils is passed. The motor housing thus forms a heat exchanger which dissipates the heat loss generated inside the electrical machine to the outside.

The motor housing is preferably formed from a plurality of housing elements which are arranged side by side along an outer circumference of the electrical machine. The individual housing elements can, for. B. be plate-shaped. In this case, the motor housing preferably comprises a plurality of plate-shaped elements which are arranged side by side in the form of a ring. The plate-shaped elements can, for. B. be L-shaped.

According to a preferred embodiment of the invention, at least one coolant channel is formed between two adjacent housing elements. A coolant channel can, for. B. can be realized that in one or both side surfaces of two adjacent housing elements a recess, such as. B. a groove or groove is provided.

The coolant channel or channels provided in the motor housing preferably each run in a plane that is transverse to the circumferential direction.

An oil, Therminol, Galden or carbon dioxide, for example, can be used as the coolant.

According to a preferred embodiment of the invention, at least one of the coils and the motor housing are hydraulically connected in series in the cooling circuit. Other components of the external rotor can also be cooled by equipping them with cooling channels and integrating them into the cooling circuit. Alternatively, further components can also be passively cooled by being mounted on or close to a cooled component.

The cooling circuit of the external rotor is preferably designed in such a way that the coolant from the coolant pump is first passed through at least one coil and then further through the motor housing designed as a heat exchanger. As mentioned above, other components of the external rotor, such as. B. an electronic unit can be integrated into the cooling circuit.

The entire cooling circuit including the pump is preferably integrated within the motor housing, in particular within the rotor, in the electrical machine.

The coils of the electrical winding are preferably formed from several rigid winding pieces. The winding can, for. B. be made in the so-called I-pin or hairpin technology. Pins or hairpins are usually made of copper, rigid winding pieces that are inserted into slots in the stator.

According to a special embodiment of the invention, the external rotor comprises a hydraulic connection part on which the housing elements are mounted and hydraulically connected.

The hydraulic connection part preferably comprises a plurality of fluid inlets and outlets, each of which communicates with a fluid inlet or fluid outlet of the coolant channels provided in the motor housing.

The housing elements are preferably mounted on the hydraulic connection part by means of a plug connection.

Insofar as “hydraulic” components or “hydraulic” are spoken of in this text, this is to be understood in such a way that the components can be designed both for conveying liquids and for conveying gases.

The hydraulic connector can, for. B. be plate-shaped. It is preferably in the form of a ring. The coolant pump is preferably mounted on the hydraulic connection part.

The hydraulic connection part is preferably part of the motor housing. It thus has the function of a heat exchanger that releases the heat generated inside the electrical machine to the environment.

In an embodiment with rigid winding pieces, the individual winding pieces are preferably open at their ends, so that the coolant can be fed in at one of the ends and discharged at the other end. In order to hydraulically connect the winding pieces to the cooling circuit, at least one hydraulic connection ring is preferably provided.

The hydraulic connecting ring preferably comprises at least one circumferential channel which is fluidically connected to several of the winding pieces and via which a coolant can be fed into the individual winding pieces or a coolant emerging from the winding pieces can be collected. According to a special embodiment of the invention, a plurality of circumferential channels can also be provided for distributing or collecting coolant in or out of the individual winding pieces.

The hydraulic connection ring is preferably designed in such a way that all winding pieces are hydraulically connected in parallel. According to a preferred embodiment of the invention, the connection ring comprises a plurality of electrical connecting elements which serve to electrically connect individual winding pieces to one another in order to form the coils of the electrical machine.

The end sections of the individual winding pieces are preferably arranged in several rows with different radii lying on a circular path.

According to a preferred embodiment of the invention, the external rotor is a brushless machine. The winding of the motor is arranged in the stator and the rotor comprises several permanent magnets that are driven by the magnetic field generated by the winding.

The external rotor according to the invention preferably also comprises an electronics unit. The electronics unit, in particular an inverter, is preferably arranged inside the motor housing, preferably inside the rotor.

According to a preferred embodiment of the invention, the electronics unit is via electrical lines that are designed as waveguides, connected to the coils of the electrical machine.

The above-mentioned electronic unit can, for. B. be mounted on the hydraulic connector so that it is also cooled by the hydraulic connector. According to another embodiment of the invention, the electronics unit is mounted on a separate heat exchanger which has at least one coolant channel through which the coolant is passed. According to a further alternative, the components located within the electronics unit are integrated directly in the cooling circuit and are therefore surrounded by the same coolant that also runs through the winding. In this case, the heat loss can be given off directly to the coolant. Electrical connecting lines between different components of the electronics unit are preferably designed as waveguides through which the coolant flows.

A winding piece according to the invention is preferably made of copper, aluminum or an alloy of one of the materials mentioned. An electrically insulating layer is preferably provided on its outer surface.

The individual coils of the winding are preferably formed from several rigid winding pieces that are electrically connected in series.

Figure list

• 1 eine Schnittansicht einer elektrischen Maschine in Form eines Außenläufers mit mehreren als Hohlleiter ausgebildeten Spulen;
• 2 eine schematische Ansicht eines Kühlkreislaufs der in 1 gezeigten elektrischen Maschine;
• 3a, 3b verschiedene Ansichten eines als Scheibe ausgebildeten hydraulischen Anschlussteils;
• 4 eine schematische Schnittansicht eines Inverters mit einem zugehörigen elektrischen und hydraulischen Anschluss gemäß einer ersten Ausführungsform der Erfindung;
• 5 eine schematische Schnittansicht eines Inverters mit einem zugehörigen elektrischen und hydraulischen Anschluss gemäß einer zweiten Ausführungsform der Erfindung;
• 6a-6c verschiedene Ansichten eines elektrischen Verbindungselements zum Befestigen und elektrischen Verbinden von Wicklungsstücken der Motorwicklung gemäß einer ersten Ausführungsform der Erfindung; und
• 7a-7c verschiedene Ansichten eines elektrischen Verbindungselements zum Befestigen und elektrischen Verbinden von Wicklungsstücken der Motorwicklung gemäß einer zweiten Ausführungsform der Erfindung.

The invention is explained in more detail below with reference to the accompanying drawing. Show it:

• 1 a sectional view of an electrical machine in the form of an external rotor with several coils designed as a waveguide;
• 2 a schematic view of a cooling circuit in FIG 1 shown electric machine;
• 3a , 3b various views of a hydraulic connection part designed as a disk;
• 4th a schematic sectional view of an inverter with an associated electrical and hydraulic connection according to a first embodiment of the invention;
• 5 a schematic sectional view of an inverter with an associated electrical and hydraulic connection according to a second embodiment of the invention;
• 6a-6c various views of an electrical connecting element for fastening and electrically connecting winding pieces of the motor winding according to a first embodiment of the invention; and
• 7a-7c different views of an electrical connecting element for fastening and electrically connecting winding pieces of the motor winding according to a second embodiment of the invention.

1 shows a sectional view of an internally cooled electrical machine 1 in the form of an external rotor. The electric machine 1 accordingly has an internal stator 2 , an outside runner 3 with several permanent magnets 4th that is around the stator 2 rotates around, and also one of several rigid winding pieces 10 formed winding. The rigid winding pieces 10 are designed as waveguides and comprise a continuous channel through which a coolant is passed to the electrical machine 1 to cool. The individual winding pieces 10 are hydraulically connected in parallel and each form part of a cooling circuit of the electrical machine 1 . An oil, Therminol, Galden or carbon dioxide, for example, can be used as the coolant.

The individual winding pieces 10 are electrically interconnected so that they have multiple coils 16 of the electric machine 1 form. The winding pieces 10 can for example be rod-shaped elements made of copper. They are provided with an electrically insulating layer on their outer surface.

In the center of 1 is the motor shaft 18th to see, which is designed here as a hollow shaft. The stator 2 in this embodiment has a supporting structure with several arms and struts. Between the motor shaft 18th and the stator structure are multiple bearings 9 intended.

The coolant pump 13th is with the motor shaft 18th coupled and is driven by this. An additional drive for the coolant pump 13th is therefore not required.

At the in 1 The illustrated embodiment of the external rotor comprises the motor housing 5 multiple coolant channels 14th through which the coolant heated by the coils is passed. The motor housing 5 thus forms a heat exchanger that is inside the electrical machine 1 dissipates generated heat to the outside.

The motor housing 5 here comprises a multiplicity of plate-shaped housing elements 6th running along a perimeter of the electrical machine 1 , Arranged side by side. The individual housing elements 6th are each L-shaped.

Between two adjacent housing elements 6th is a coolant channel 14th available. The individual coolant channels 14th are realized in that in one or both side surfaces of two adjacent housing elements 6th a recess such. B. a groove or groove is provided. This allows the coolant channels 14th can be produced particularly easily and inexpensively.

At least some of the ones in the engine case 5 provided coolant channels 14th is hydraulically connected in parallel and coolant flows through it in parallel.

The one or those in the motor housing 5 provided coolant channels 14th each run in a plane that is transverse to the circumferential direction. They preferably do not run in the circumferential direction.

According to a special embodiment of the invention, the external rotor comprises a hydraulic connection part 7th , on which the individual housing elements 6th mounted and hydraulically connected. The hydraulic connection part 7th comprises a plurality of fluid inlets and outlets on its outer circumference, each with a fluid inlet or fluid outlet of the coolant channels provided in the motor housing 14th communicate. The housing elements 14th are via plug connections 15th on the hydraulic connection part 7th assembled.

The hydraulic connection part 7th is plate-shaped and has one or more internal fluid channels 8th . The coolant pumps 13th are on the hydraulic connection part 7th mounted and hydraulically connected to it.

The individual winding pieces 10 are preferably open at their ends, so that the coolant can be fed in at one of the ends and discharged at the other end. To the winding pieces 10 To be hydraulically connected to the cooling circuit, two hydraulic connection rings are required 11 , 12th intended. Any hydraulic connection ring 11 , 12th comprises at least one circumferential channel that connects to a plurality of the winding pieces 10 is fluidly connected and through which the coolant in the individual winding pieces 10 fed in or one from the winding pieces 10 escaping coolant can be collected. All winding pieces 10 are preferably connected hydraulically in parallel.

The in 1 The external rotor shown preferably also comprises an electronics unit (not shown), in particular an inverter for controlling the currents flowing through the coils. The electronics unit is arranged inside the motor housing. It is preferably on the hydraulic connection part 7th mounted so that they are from the hydraulic connector 7th is cooled with.
the end sections 8th of the individual winding pieces 10 are preferably arranged in several, in particular circular, rows. They preferably all end at the same axial height, ie approximately in the same plane. This facilitates the electrical contacting of the individual winding pieces 10 as well as their hydraulic connection to the cooling circuit.

2 shows a schematic view of a cooling circuit 17th of the electric machine 1 of 1 . In the exemplary embodiment shown, the cooling circuit comprises at least the following components of the electrical machine 1 : the spools 16 , part of the housing 5 (plate-shaped housing elements 6th ), the hydraulic connection part 7th and at least one coolant pump 13th .

The coolant flow is from the coolant pumps 13th towards the coils 16 , further to part of the motor housing 5 , which serves as a heat exchanger, and via the hydraulic connection part 7th back to the pumps. Optionally, more or fewer components can be integrated into the cooling circuit.

3a , 3b show different views of a disk-shaped hydraulic connection part 7th . The annular disc has a plurality of slots on its circumferential surface 28 , on which the individual housing elements 6th of the motor housing 5 be infected. The hydraulic connection part 7th further includes multiple passages 19th for electrical lines 24 with which the electronics unit 27 is connected (see 4th ). On the inner surface of the hydraulic connection part 7th (in the 3b shown) are also hydraulic connections 20th for the coolant pumps 13th intended. Mounting points for the coolant pumps 13th are with the reference number 21 marked.

4th shows an electronics unit 27 with a combined electrical / hydraulic connection with which it is connected to one of the coils 16 of the electric machine 1 connected. With an electric machine 1 with three coils 16 there are three such electrical / hydraulic connections.

The electronics unit 27 - in this case an inverter - is on a heat exchanger 29 arranged, the at least one coolant channel 8th has, which is flowed through by coolant. The electrical / hydraulic connection of the inverter comprises an electrical line 24 leading to one of the coils 16 leads and which is designed as a waveguide. At the connection-side end of the electrical line 24 is a clamp 25th in the form of a cable lug provided by means of a banjo bolt 26th is clamped. the clamp 25th has an annular channel inside, which is connected to several side openings of the banjo bolt 26th communicates so that the coolant from the heat exchanger 29 over the hollow screw shaft and the side openings 26th into the electrical line 24 can be fed. A fluid flow in the opposite direction is of course also possible.
The inverter is via a power rail 22nd that from the clamp 25th is electrically contacted, connected to the electrical / hydraulic connection. Between the power rail 22nd and the heat exchanger 29 there is an electrical insulator 23 which also serves as a seal.

5 FIG. 11 shows another embodiment of an electrical / hydraulic connection which is similar to FIG 4th is constructed. The connection in turn comprises a banjo bolt 26th who have favourited a power rail 23 contacted and runs through the latter. In contrast to the embodiment of 4th is the electrical line 24 but not by means of a clamp 25th connected, but in the screw head of the banjo bolt 26th there is a hole where the electrical line is located 24 connected. The cross-section of the hole is based on the profile of the pipe 24 customized.

6a-6c show different views of an electrical connector 30th according to a first embodiment of the invention, on which several winding pieces 10 attached to the motor winding and electrically connected to each other. The connecting element 30th is made of metal and in this embodiment comprises two channel-shaped recesses 31 , in each one end of a winding piece 10 can be inserted. The cross section of the groove-shaped recess is based on the profile of the winding piece 10 adapted so that the latter can be inserted or clipped in essentially without play. Each of the winding pieces 10 is by means of solder 34 on the connecting element 30th attached and electrically contacted. Several of the winding pieces 10 can thus become a coil 16 be connected electrically. The winding piece shown 30th includes exactly two connections for winding pieces 10 ; however, more than two connections can also be provided.

7a-7c show different views of an electrical connector 30th for the electrical connection of winding sections 10 the motor winding according to a second embodiment of the invention. In this embodiment, the connecting element comprises 30th several through openings 32 each one end of a winding piece 10 take up. The ends of the winding pieces 10 in this case must be in the individual through openings 32 be threaded. In the connecting element 30th there are also several auxiliary holes 33 provided that transversely to the through openings 32 run and each in one of the through openings 32 flow out. The auxiliary holes 33 allow the ends of the winding pieces 10 to solder. The solder is here schematically with the reference number 34 marked. In turn, two or more than two connections for winding pieces can be used 10 be provided.

The fasteners 30th are preferably in the in 1 hydraulic connection rings shown 11 , 12th integrated. Thus, the individual winding pieces 10 can be connected electrically and hydraulically at the same time.

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was 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.

Patent literature cited

• DE 102014201305 A1 [0003]
• DE 102013205418 A1 [0003]

Claims (17)

Electrical machine (1) in the form of an external rotor with: an internal stator (2); an external rotor (3) surrounding the stator (2); and a motor housing (5), characterized in that the stator (2) comprises at least one coil (16) designed as a waveguide, which forms the winding of the electrical machine (1) and is part of a cooling circuit (17) of the electrical machine (1) wherein the at least one coil (16) has a hollow interior through which a coolant is pumped; and that at least one coolant pump (13) is provided for pumping the coolant through the coil (16) which is arranged in a space within the motor housing (5). Electric machine (1) according to Claim 1 , characterized in that the coolant pump (13) is coupled to the motor shaft (18) and is driven by this. Electric machine (1) according to Claim 1 or 2 , characterized in that the motor housing (5) has at least one coolant channel (14) through which coolant is passed. Electrical machine (1) according to one of the preceding claims, characterized in that at least one of the coils (16) and the motor housing (5) or its at least one coolant channel (14) are hydraulically connected in series in the cooling circuit. Electrical machine (1) according to one of the preceding claims, characterized in that the coils (16) are each formed from a plurality of rigid winding pieces (10). Electrical machine (1) according to one of the preceding claims, characterized in that the motor housing (5) comprises a plurality of housing elements (6) which are arranged side by side along a circumference of the electrical machine (1). Electric machine (1) according to Claim 6 , characterized in that a coolant channel (14) is formed between two adjacent housing elements (6). Electric machine (1) according to Claim 6 or 7th , characterized in that the housing elements (6) are mounted on a hydraulic connection part (7) and hydraulically connected to it. Electric machine (1) according to Claim 8 , characterized in that the hydraulic connection part (7) is part of the motor housing (5). Electric machine (1) according to Claim 8 or 9 , characterized in that the housing elements (6) are each mounted on the hydraulic connection part (7) by means of a plug connection. Electric machine (1) according to Claim 1 , characterized in that the coolant pump (13) is mounted on a hydraulic connection part (7). Electric machine (1) according to one of the Claims 8 to 11 , characterized in that the connection part (7) is plate-shaped. Electric machine (1) according to Claim 1 , characterized in that the winding of the electrical machine (1) is formed from several rigid winding pieces (10) and at least one distributor ring (11) is provided to which several of the winding pieces (10) are hydraulically connected. Electrical machine (1) according to one of the preceding claims, characterized in that the cooling circuit (17) is designed in such a way that the coolant from the coolant pump (13) through the at least one coil (16) and further through the motor housing designed as a heat exchanger ( 5) is sliding. Electrical machine (1) according to one of the preceding claims, characterized in that an electronic unit (27) for controlling the current flowing through the coils is arranged in the interior of the motor housing (5). Electric machine (1) according to Claim 15 , characterized in that the electronics unit (27) is connected via electrical lines (24) to the coil or coils (16) of the electrical machine (1), the electrical lines (24) being designed as waveguides. Electric machine (1) according to Claim 15 , characterized in that the electronics unit is mounted on the hydraulic connection part (7) so that it is cooled by the hydraulic connection part (7).

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