Direct-cooled electric machine having a potted winding head

Abstract

The invention relates to an electric machine (1) having the features of patent claim 1 and to a method for producing a waveguide winding having a potted winding head (5).

Description

[0001] Internally cooled electrical machine with a cast winding head

[0002] The invention relates to an internally cooled electrical machine comprising a rotor and a stator with a waveguide winding and a hydraulic connection part for supplying or collecting coolant, as well as a method for producing such an electrical machine. The invention further relates to an electrical device comprising a waveguide winding and a hydraulic connection part.

[0003] BACKGROUND OF THE INVENTION

[0004] Internally cooled electric machines with a waveguide winding manufactured using pin or hairpin technology are known from the prior art. The pins or hairpins are usually made of copper waveguides that are inserted into slots in the stator of the electric machine and generate a magnetic field during operation. The waveguides have a continuous channel through which a coolant is passed to cool the electric machine during operation.

[0005] DE 10 2018 129 226 A1, for example, shows an electrical machine with a rotor and a stator with a waveguide winding. It also describes a hydraulic connector with connections for a plurality of waveguides, by means of which a coolant can be fed into the waveguides and / or coolant escaping from the waveguides can be collected. The hydraulic connector can be sealed with a potting compound. However, connecting the waveguides to the hydraulic connector is relatively complex and can be further simplified.

[0006] OBJECT OF THE INVENTION

[0007] It is therefore an object of the present invention to provide an internally cooled electrical machine with a waveguide winding whose waveguide winding ends can be electrically interconnected particularly easily and connected to a hydraulic cooling circuit and sealed. This object is achieved according to the invention by the features stated in claim 1. Further embodiments of the invention emerge from the subclaims.

[0008] According to the invention, an electrical machine is proposed which comprises at least the following components:

[0009] - a runner,

[0010] - a stator with a winding formed from waveguides through which a coolant is passed to cool the winding during operation,

[0011] - at least one winding head on which open ends of the waveguides are arranged; and

[0012] - a hydraulic connection part to which the waveguides are hydraulically connected, wherein the hydraulic connection part has at least one channel via which a coolant can be fed into the waveguides or via which a coolant emerging from the waveguides can be collected.

[0013] According to the invention, the winding head is encapsulated in a potting compound, with the open ends of the waveguides protruding from the potting compound. According to the invention, the winding head does not comprise a pouring mold, such as a tub, into which the potting compound is poured. Potting the winding head is preferably produced using a tool that encloses the stator on its inside and outside and provides a space in the area of ​​the winding head into which the potting compound can be poured. The tool is removed after potting.

[0014] All principles of this invention are applicable to any other electrical device having a waveguide winding for generating an electromagnetic field, such as transformers or induction coils having a waveguide winding.

[0015] The potting compound is preferably applied directly to the stator's laminated core and preferably extends from the laminated core to just below the open ends of the waveguides. Optionally, an air gap can be provided between the potting compound and the laminated core, with the potting compound directly adjacent to it. Alternatively, a disk, such as a retaining disk, can be provided between the laminated core and the potting compound, providing passages for the individual waveguides. The disk can be positioned at a distance from the laminated core.

[0016] When manufacturing an electrical machine with a cast winding head, where there is a distance or air gap between the laminated core and the casting compound, a casting mold is preferably used, which is removed again after the casting has been made. In this case, the casting mold is first positioned in the area of ​​the winding head, filled with casting compound, and removed again after the casting compound has hardened: At the location of the casting mold, a distance or air gap then remains between the laminated core and the casting compound. The casting mold can be made of several parts for this purpose, for example. However, it can also be made of a material such as wax or a plastic with a low melting point, which can be removed through heat treatment.

[0017] The hydraulic connection part is preferably at least partially embedded in the casting compound. By embedding the hydraulic connection part in the casting compound, it is simultaneously mechanically fixed and fluidically sealed.

[0018] The hydraulic connector can be designed either as a single piece or in multiple pieces. In a multi-piece design, for example, feet or mounting bases can be provided, which are embedded in the potting compound in a first step. A second part of the hydraulic connector is then mounted on the feet or mounting bases. In a preferred embodiment, the hydraulic connector has web-like walls that are partially immersed in the potting compound and enclosed by it.

[0019] The walls can have an anchoring section that positively secures the hydraulic connection part in the casting compound. According to one embodiment, the anchoring section can comprise one or more projections or transverse bores projecting laterally from the wall.

[0020] The potting compound may comprise an epoxy resin, a thermoplastic, or a silicone, or a combination of several of the aforementioned materials. It is preferably electrically insulating.

[0021] In addition to the hydraulic connection part, electrical connecting elements that electrically connect the waveguides can also be embedded in the potting compound.

[0022] In a specific embodiment, the at least one channel provided in the hydraulic connection part comprises first sections with a larger cross-section and second sections with a smaller cross-section. Preferably, there are no waveguide ends in the second sections.

[0023] According to a first embodiment of the electrical machine, only one of the winding heads is encapsulated. In a second embodiment of the electrical machine, both winding heads are embedded in encapsulation compound. A hydraulic connection part is provided on at least one of the winding heads, which is also embedded in the encapsulation compound.

[0024] The waveguides of the winding can be designed as rigid waveguide elements arranged in slots of the stator. Rigid waveguide elements are, for example, pins or hairpins with a continuous channel through which a coolant is passed. However, the invention is also suitable for other winding types, such as a concentrated winding or an inserted winding.

[0025] In a special embodiment of the invention, the grooves are also potted, ie the waveguides arranged in the grooves are encased in the potting compound.

[0026] The hydraulic connection part can be trough-shaped and have web-like walls.

[0027] The hydraulic connection part is preferably designed as a ring-shaped hydraulic connection ring. Alternatively, it could also consist of individual angle segments.

[0028] The hydraulic connection part can be made of plastic, for example, but also of metal.

[0029] The individual waveguides are preferably open at their ends, so that the coolant can be fed in at one end and discharged at the other. However, the invention also works for waveguides that are closed at the end and have a side tap.

[0030] In a special embodiment, the hydraulic connection part comprises at least one coolant connection (supply connection) via which the coolant can be fed into the connection part from the outside, as well as a coolant connection (return connection) via which the coolant can be discharged to the outside.

[0031] The hydraulic connection part preferably comprises several phase connections (L1-L3) that are electrically connected to the waveguides. A waveguide according to the invention is preferably made of copper, aluminum, or an alloy of one of the aforementioned materials. An electrically insulating layer is preferably provided on its outer surface.

[0032] The hydraulic connection part preferably comprises several circumferential channels for distributing or collecting coolant into or from the individual waveguides.

[0033] The invention further relates to a method for producing an electrical device, in particular an electrical machine, with a

[0034] Waveguide winding. According to the invention, the method comprises at least the following steps:

[0035] Potting a portion of the electrical device on which open ends of the waveguides are arranged, such as an open winding head, with a potting compound such that the open ends of the waveguides protrude from the potting compound; and;

[0036] Allow the casting compound to harden.

[0037] Before or after pouring, one or more additional components, such as:

[0038] B. a hydraulic connection part or electrical connecting elements, are positioned in the area of ​​the cast section and embedded in the casting compound.

[0039] In the case of an electrical machine with a stator and a rotor, the potting of the open winding overhang can be created by adding a potting compound to the other side of the stator, i.e. at the other winding overhang, and then guiding the potting compound through the stator's slots to the open winding overhang. In the simplest case, the potting compound flows from one winding overhang to the other under the force of gravity. Preferably, a vacuum is created on the side of the open winding overhang, which draws the potting compound from the other side of the stator through the slots to the open winding overhang. For potting the section, for example, a tool can be used that encloses at least the section of the electrical device where the open ends of the waveguides are arranged - in the case of an electrical machine: the stator in the area of ​​the open winding overhang - and defines a space into which the potting compound is poured.The tool is removed after the casting compound has hardened.

[0040] In the case of an electrical machine with a stator and a rotor, the potting of the open winding head can be achieved by applying a potting compound to the other side of the stator, i.e., the other winding head, and then guiding the potting compound through the stator slots to the open winding head. In the simplest case, the potting compound flows from one winding head to the other by gravity. Preferably, a vacuum is created on the side of the open winding head, which draws the potting compound from the other side of the stator through the slots to the open winding head.

[0041] BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The invention is explained in more detail below with reference to the accompanying drawings. They show:

[0043] Fig. 1 is a sectional view of an electrical machine with a waveguide winding according to a first embodiment of the invention, in which one of the two winding heads is cast with a casting compound;

[0044] Fig. 2 is a sectional view of an electrical machine with a waveguide winding according to a second embodiment of the invention, in which both winding heads are encapsulated;

[0045] Fig. 3 is an enlarged sectional view of the open winding head of the electrical machine of Fig. 1; Fig. 4 is a sectional view of a hydraulic connection part of the electrical machine of Fig. 1;

[0046] Fig. 5 is an enlarged sectional view of the open winding head of an electrical machine according to another embodiment.

[0047] Fig. 1 shows a sectional view of a three-phase electrical machine 1 with a stator 2, a rotor (which is not shown for reasons of clarity) and a winding 4 formed from rigid waveguides 14 for generating an electromagnetic field. The rigid waveguides 14 are designed as hairpins in this example and comprise a continuous channel 21 through which a coolant is passed in order to cool the electrical machine 1 during operation. The hairpins are usually made of copper. The outer surface of the hairpins is provided with an electrically insulating coating. The phase connections are designated L1, L2; the third phase connection L3 is not shown.

[0048] The stator 2 comprises, in a known manner, a laminated core 12 with slots 13 in which the waveguides 14 are arranged. The waveguides 14 have open ends 6, which in this exemplary embodiment are all arranged on the same side of the stator 2 and form an open winding head 5a there. The winding head 5 located on the other side of the stator 2 does not comprise any open waveguide ends and can thus be referred to as a "closed" winding head 5b.

[0049] The stator 2 also includes a hydraulic connection part 7 arranged on the open winding head 5a, to which the waveguides 14 are hydraulically connected. The hydraulic connection part 7 is annular and comprises two channels 8, through which coolant is fed into the waveguides 14 and through which coolant escaping from the waveguides 14 can be collected. In the illustrated embodiment, one of the channels 8 is a supply channel 15, through which the coolant is fed into the waveguides 14. The other channel 8 is a return channel 16, in which the coolant escaping from the waveguides 14 is collected. During operation of the electric machine 1, the coolant is fed from the outside into the connection part 7 via a coolant connection 10 (supply connection), then enters the supply channel 15, and from there flows through the individual waveguides 14.The coolant exits the waveguides 14 again on the same side of the stator 2, is collected in the return channel 16 and is discharged to the outside via a central coolant connection 11 (return connection).

[0050] As can be seen, the open winding head 5a is partially encapsulated in an electrically insulating potting compound 20, with the open ends 6 of the waveguides 14 protruding from the potting compound 20. The hydraulic connection part 7 is also partially embedded in the potting compound 20. This has the advantage that the hydraulic connection part 7 is simultaneously mechanically fixed and fluidically sealed by the potting compound 20. No further measures are required to secure the connection part 7 or to seal it.

[0051] In the first embodiment shown in Fig. 1, the closed winding head 5b shown in the image below is not potted. Fig. 2 shows a second embodiment in which the closed winding head 5b is also potted. Furthermore, in this embodiment, the sections of the waveguides 14 running in the grooves 13 are surrounded by potting compound 20. Apart from that, the first embodiment shown in Fig. 1 and the second embodiment shown in Fig. 2 are identical, which is why reference is made to the description of Fig. 1 with regard to the other components.

[0052] Fig. 3 shows an enlarged sectional view of the open winding head 5a of the electrical machine 1 from Fig. 1. It can be seen that the hydraulic connection part 7 is designed as a trough-shaped element with web-like walls 9 which delimit the individual channels 8. Outer walls are provided with the reference number 9. An inner wall between the supply channel 15 and the return channel 16 is designated by the reference number 9a. Fig. 4 shows an enlarged sectional view of the open winding head 5a of the electrical machine 1. The sectional surface runs transversely to the longitudinal axis of the electrical machine 1 through the hydraulic connection part 7, so that the internal structure of the connection part 7 can be clearly seen. The hydraulic connection part 7 has a supply channel 15 and a return channel 16. Each of the channels 15, 16 has a plurality of first sections with a large cross-section and second sections with a small cross-section.The first and second sections alternate in the circumferential direction. In segments where one channel 15, 16 has a large cross-section, the other channel 15, 16 has a second section with a small cross-section. Several waveguide ends 6 are arranged in the area of ​​the first sections. No waveguide ends 6 are arranged in the area of ​​the second sections. The channels 8 extend essentially over the entire circumference of the hydraulic connection part 7.

[0053] Finally, Fig. 5 shows a further embodiment of an electrical machine 1, in which the walls 9 comprise an anchoring section 19 to better fix the hydraulic connection part 7 in the potting compound 20. In the illustrated embodiment, the wall 9 has feet at its free end. Other positive-locking connections can be implemented similarly.

Claims

Patent claims 1. Electrical machine (1 ), comprising: - a stator (2) with a laminated core (12) and a winding (4) formed from waveguides (14), through which a coolant is passed in order to cool the winding during operation, and - at least one winding head (5), on which open ends (6) of the waveguide (14) are arranged; wherein the winding head (5) is cast with a casting compound (20), the winding head (5) has no pouring mold for the casting compound (20), and the open ends (6) of the waveguide (14) protrude from the casting compound (20); characterized in that an air gap or a disk is arranged between the casting compound (20) and the laminated core (12), to which the casting compound (20) is directly adjacent.

2. Electrical machine according to claim 1, characterized in that a hydraulic connection part (7) is provided which is at least partially embedded in the casting compound (20).

3. Electrical machine according to claim 2, characterized in that the hydraulic connection part (7) comprises undercuts in order to better fix it in the casting compound.

4. Electrical machine according to one of the preceding claims, characterized in that the potting compound (20) comprises an epoxy resin, thermoplastic or a silicone.

5. Electrical machine according to one of the preceding claims, characterized in that some of the waveguides (14) in the region of the open winding head (5a) are electrically connected to others of the waveguides (14) via electrical connecting elements, wherein the connecting elements are also embedded in the casting compound (20).

6. Electrical machine according to one of the preceding claims, characterized in that the stator (2) comprises two winding heads (5), both of which are embedded in potting compound (20).

7. Electrical machine according to claim 1, characterized in that the stator (2) is also cast with casting compound (20) in the region of its slots (13).

8. Electrical machine according to one of the preceding claims, characterized in that the hydraulic connection part (7) is trough-shaped, has openings, and has subdivisions for guiding and distributing the coolant.

9. An electrical device comprising a winding (4) formed from waveguides (14) for generating an electromagnetic field, said winding comprising at least one section on which open ends (6) of the waveguides (14) are arranged, and comprising a hydraulic connection part (7) to which the waveguides (14) are hydraulically connected; wherein at least the section is cast with a casting compound (20) and the open ends (6) of the waveguides (14) protrude from the casting compound (20), characterized in that an air gap or a disc is arranged between the casting compound (20) and the laminated core (12), to which the casting compound (20) is directly adjacent.

10. A method for producing a stator (2) of an electrical machine (1) comprising: a laminated core (12) with slots (13); a winding (4) formed from waveguides (14), through which a coolant is passed to cool the winding (4) during operation; first and second winding heads (5) arranged on opposite sides of the laminated core (12), at least one of which comprises a section on which open ends (6) of the waveguides (14) are arranged; characterized in that at least the following steps are carried out during the production of the stator (2): - Supplying a casting compound on the side of the first winding head (5), - passing the potting compound through the grooves (13) of the stator to the second winding head (5) so that the open ends (6) of the waveguides (14) protrude from the potting compound (20); and - Allow the casting compound (20) to harden.

Images