EP3895286A1

EP3895286A1 - Cooling channel for a winding overhang of an electrical machine

Info

Publication number: EP3895286A1
Application number: EP19828236.0A
Authority: EP
Inventors: Markus Michael; Martin STÖCK
Original assignee: Jheeco eDrive AG Liechtenstein
Current assignee: Jheeco eDrive AG Liechtenstein
Priority date: 2018-12-12
Filing date: 2019-12-11
Publication date: 2021-10-20
Also published as: DE102018131961A1; WO2020120622A1; CN113196624A; US20220037946A1

Abstract

The invention relates to a cooling channel for a winding overhang of an electrical machine, wherein, in order to conduct a cooling fluid, said cooling channel is designed with at least one inflow (25) and at least one outflow (26) and is annular for provision around the winding overhang. The cooling channel has a plurality of partitions (31; 32) arranged such that parallel sub-channels are formed between the at least one inflow (25) and at least one outflow (26), and the inflow (25) is arranged radially outwardly, relative to the cooling channel, and the outflow (26) radially inwardly, or vice versa.

Description

Cooling channel for a winding head of an electrical machine

description

The invention relates to a cooling channel for a winding head of an electrical machine and a stator with such a cooling channel.

The term “electrical machine” is essentially to be understood as an electrical motor or an electrical generator with a stator and a rotor, the rotor being common to the stator

Center axis is rotatably mounted. The stator comprises a laminated stator core and a current-carrying winding. The winding is preferably arranged in axially extending grooves of the stator lamination stack distributed over the circumference. The winding forms a plurality of coils / half-coils, one of which

Coil / half-coil two running in different slots

Current conductor sections and two / one connecting section connecting these current conductor sections at the end of the stator laminate core. Only the winding portion running axially within a slot contributes to the torque; it is also called the active length. In contrast, the parts of the

Winding, which electrically connect the active lengths at the ends of the laminated core, torque-blind; this part lying axially outside the laminated core is also referred to as a winding head. A winding end can consequently be regarded as the part of a winding which projects axially over a stator laminated core.

Several conductor sections can be placed in a slot (multi-layer system).

With increasing temperature, the efficiency of electrical machines, in particular traction motors for electric vehicles, decreases, which is why the electrical machines are known to be cooled by means of a cooling fluid. This takes place, for example, via a cooling sleeve / channel through which water flows or a cooling jacket which indirectly cools a stator or its stator jacket. Indirect cooling means that the cooling fluid and the heat source have no direct contact. In order to increase the efficiency, it is also known to cool winding heads directly. Dielectric oil, which is pumped through the winding head, is mostly used here. US 2017 310 189 describes a winding head cooling in the form of a cooling cap for electric motors.

DE 10 2015 220 112 A1 describes a cover unit for a winding head of an electrical machine, the cover unit having a cooling channel which extends along the circumferential direction of the stator.

Furthermore, it is known that a winding can also be composed of rod conductors which are inserted or drawn into the slots in a laminated core.

The rod conductors are connected in pairs to form half coils. This can be done directly, for example by bending one another and welding the rod conductors directly, or indirectly, for example by connecting bars bridging the distance between two rod conductors (synonym forehead connector).

Rod conductors can be in one piece (solid conductor) or in multiple pieces (wire strands) and can be designed, for example, in the form of hairpins or I-shaped (I-pins). Bar conductors can in particular also be designed as compression-molded and twisted wire strands.

The winding head is used to arrange them inside the stator

Segment conductors or rod conductors interconnected at their ends and according to a predetermined pattern.

For directly connected rod conductors, for example hairpin windings, winding head cooling is easy to do by fitting a cooling cap

realize. Direct cooling is difficult to implement for winding heads equipped with connection bars, since the individual connection bars must be held by holders. In particular for mobile applications in which strong vibrations occur, the secure hold of connection bars is endangered. For this reason, connection bars for mobile applications are usually placed directly on top of one another and potted with resin. This ensures the electrical contact from an interruption, for example

Vibration-induced fatigue fracture in a welding point, however, has disadvantages in cooling the winding head. It is therefore an object of the present invention to provide direct and improved cooling for an electrical machine or its winding head, in particular a winding head equipped with connecting webs.

For this purpose, a cooling duct according to claim 1 is provided according to the invention. In detail, a cooling duct for a winding head of an electrical machine is provided, the cooling duct for guiding a cooling fluid with at least one inflow and at least one outflow and for arranging it around the

Winding head is annular. The cooling duct has a multiplicity of partition walls which are arranged such that parallel subchannels are formed between the at least one inflow and the at least one outflow, the inflow being arranged radially on the outside, with respect to the cooling duct, and the outflow being arranged radially on the inside or the inflow are arranged radially inside and the drain radially outside. This has the advantage that defined channels are formed by means of the partition walls and thus the flow of the cooling fluid describes defined paths. This ensures that all segment conductors are cooled, preferably cooled to the same degree, and thus the efficiency of the electrical machine is increased. Hotspots due to unequal

Coolant distribution can be avoided or reduced. As well

allow defined cooling channels a technically advantageous design of the flow. For example, a reduction or an increase in eddies of the cooling flow and / or a reduction or increase in the cooling flow rate and / or a reduction or increase in the

Cooling flow amount can be influenced. This allows the cooling effect of the

Winding head can be improved.

Parallel subchannels are understood to mean a fluidic parallel connection, not a geometric parallelism of the subchannels.

The partitions also allow or are preferably designed to serve as a fastening or holder for the connecting webs of the end winding. One or more connection bars between the

Partitions arranged or held in a predetermined place and prevented from slipping or moving. This ensures the electrical contact between the connection bars and the stator ladders and protects them against an interruption, for example due to vibrations. The fluid flow preferably flows from radially outside to radially inside. As a result, the fluid outlet can optionally be hollow with a cooling outlet

Rotor shaft, which is flowed through by a cooling fluid, are united.

The inflow and / or the outflow are preferably each formed as an annular gap, the inflow and the outflow being formed by an annular

Ceiling section of the cooling channel are separated from each other. This preferred embodiment has the advantage that a steady and constant inflow and outflow of the cooling fluid for the winding head is made possible.

Preferably at least part of the plurality of partitions is

arranged radially and form radial partitions. The partitions form planes that are parallel to the central axis of the stator. This has the advantage that the interconnection bars can be individually separated from one another and can be held more securely. This is particularly the case if the

Interconnection bars are formed from an arc and two radial bars and the bars are / are arranged between two partitions.

It is also advantageous if at least part of the large number of

Partitions are formed in a circular arc and are arranged in groups concentrically to one another in particular. This is especially true for the

Interconnection bars are advantageous if they have an interconnection arch or are arch-shaped. As a result, the interconnection bars can be arranged and held at a predetermined location.

Furthermore, it is advantageous if at least some of the plurality of partition walls have and / or form insulating rings arranged concentrically and parallel to one another - in the geometric sense. These insulation rings can be understood as annular disk-shaped base plates for the connecting webs and are in particular arranged perpendicular to the central axis of the stator or horizontally. Alternatively, these partitions can alternatively have a conical outer surface. They help to fluidically and / or electrically separate different interconnection levels and to hold interconnection bridges. In order to form channels around the interconnection bars, the radial

Partitions, the arched partitions and / or the horizontal

Partitions (also referred to as insulation rings), always or at least partially, be arranged perpendicular to each other. This helps the cooling channel to provide more mechanical stability and more orderly flow paths for the

Cooling fluid.

In order to fasten or hold the connecting webs within the partition walls, these partition walls have fastening elements, in particular

Clamping elements or knobs. These fastening elements make it possible to use the cooling channel for different shapes or thicknesses

Enable interconnection bridges and thus make them more flexible. In addition, the cooling fluid can flow through unhindered by the spacing or space generated by the fastening elements between the partition wall and the connecting web and can cool the connecting webs better.

Alternatively, however, the connecting webs can also be positioned loosely, that is to say with play, within the partition walls. So game stands for

Establishment of the electrical connection between interconnection bars and wire ladders. This can reduce tolerance dependencies.

The plurality of partition walls is preferably formed from an elastic and / or electrically insulating material. This can in particular

Design tolerances can be better balanced and the cooling channel can be attached to the winding head more easily.

The partitions can be connected to one another in the form of tongue and groove connections for sealing the cooling duct or parts of the cooling duct. The partition walls can alternatively or additionally have sealing means such as sealing lips for the fluidic sealing of touching

Partitions. Sealants can be designed as independent components, such as O-rings, or as molded components of a multi-component partition. In particular, sealants can be between horizontal

Partition walls or insulation rings lying one above the other can be provided. In a further advantageous embodiment, the cooling duct is formed in one or more parts. A multi-part channel allows the entire

Design flexibly as required; the number of partitions and / or outer walls can be adjusted and varied depending on the end winding.

It is also advantageous if the cooling duct has a sealing element, in particular a sealing mat, as the base component and a stator cooling housing as the outer side wall. This particular embodiment shows that already existing components of the stator are used for the cooling channel and additional components for the channel can thus be saved.

According to the invention, a stator according to claim 11 is provided. This stator, which is provided in particular for an electric motor, is designed with a plurality of rod conductors, the stator having at least one cooling duct according to the present invention and the partition walls of the cooling duct being arranged between at least some of the rod conductors. In this embodiment, the rod conductors extend into the cooling channel and are electrically connected to the interconnection webs arranged in the cooling channel. In a further embodiment, the connecting webs can protrude from the cooling channel and can be electrically connected to the rod conductors outside the cooling channel.

The stator preferably has a plurality of interconnection bars which correspond or correspond to the bar conductors.

Furthermore, an electrical machine with a cooling duct according to the present invention or a stator as previously disclosed is provided according to the invention.

The figures described below refer to preferred ones

Embodiments of the cooling duct according to the invention as well as the

Stator according to the invention, these figures not being used as a limitation, but essentially to illustrate the invention. Elements from different figures, but with the same reference numerals are identical; therefore, the description of an element from a figure is also valid for elements from other figures with the same designation or numbering. Show it:

Fig. 1 is a perspective view of a stator

composite winding;

FIG. 2 shows a side view of the stator according to FIG. 1;

3 shows a basic form of winding head cooling for a stator according to FIGS. 1 and 2.

4A shows a cross section of a stator half according to FIG. 3 on a

Interconnection level;

Fig. 4B is a schematic plan view of a stator half according to

Fig. 3 with different ring areas.

FIG. 5A shows a top view of a stator according to FIG. 3 in a

Version with only radial

Partitions with a step cut according to Fig. 5B.

5B shows a cross section along the axis of the stator of FIG.

5A, which explains the view of and into the cooling duct;

6A shows a plan view of a stator according to FIG. 3 in a second embodiment variant with a step cut according to FIG. 6B with fluidically connected in parallel

Interconnection levels and interconnection web groups;

6B shows a cross section along the axis of the stator of FIG.

6A, which explains the view of and into the cooling duct;

FIG. 7 shows a plan view of a stator according to FIG. 3 for a

Design of the fluid flow only in a groove area with radial partition walls, without a rod conductor,

Connection webs and cooling channel; 8A and 8B are perspective views of a cover unit for a winding head of a stator according to FIG. 7;

9A is an exploded view of an insulation ring

Cooling channel with connection web groups for one

Design of the fluid flow for a

3 in a further embodiment variant only for the winding head cooling of a stator

Bridging area;

Fig. 9B is a top view of the isolation ring shown in Fig. 9A;

10A and 10B are perspective views of assembled

Isolation rings from a cooling channel without

Interconnection bars for winding head cooling for a stator from FIG. 3 according to a preferred one

Design variant;

11 shows the assembled insulation rings according to FIGS. 10A and 10B with connecting webs;

FIGS. 12A and 12B show the assembled insulation rings according to FIGS. 10A and 10B with a cover unit or cover;

13 shows a stator with a cooling channel according to the present

Invention and with drawn fluid flows according to the preferred embodiment;

14 shows a longitudinal section through an upper part of a stator according to the preferred embodiment variant, in particular its winding head with a cooling channel according to the invention, fluid flows being shown;

15 shows an exploded view of a stator according to the invention with two winding heads and cooling channels according to the preferred embodiment variant; and 16 shows four different design variations of the

Partition walls within a cooling channel with interconnection bars arranged therein.

Fig. 17 shows a construction variant for the arrangement of

Folded elements on partitions

Fig. 18 shows a variant of a cover part with an extended

Inflow opening.

FIGS. 1 and 2 show a stator with one made of bar conductors and

Compound winding interconnection bars.

1 shows a stator 1 with a cylindrical stator jacket or

Stator laminated core 2, in which the elongated stator bar conductors 6 are arranged concentrically around the axis of the stator or stator jacket and in corresponding grooves or grooves in the stator jacket 2. A first end winding 3 (on side A) and a second end winding 4 (on side B) are formed at the end of stator 1, starting from the top and bottom of stator sheath 2.

Both winding heads 3, 4 each have interconnection levels 5, which are formed from interconnection bars 9. A connecting web 9 connects two rod conductors 6, which extend from the stator jacket 2 into the winding head 3, 4. The winding head 4 differs from the winding head 3 in that an interconnection level 7 with three phase connections 8 is additionally installed in the winding head 4. The connecting webs 9 are arcuate rod conductors with additional rod conductors running radially to the axis of the stator, the function of which is to electrically connect the rod conductors 6 in pairs. Here are the

Bar conductors 6 are connected to one another according to a predetermined pattern, for which reason the distance and the number of connecting webs 9 designed as bar conductors between the paired bar conductors 6 are predetermined. The

Winding heads 3 and 4 are ring-shaped or cylindrical-shaped and are essentially formed by the interconnection levels 5, which are arranged concentrically and parallel to one another. The phase connection 8 in the designated interconnection level 7 consists of three contacts, preferably for one

Three-phase connection. The bar conductors 6 are designed such that they extend up to a certain interconnection level 5 in the winding head 3 and in the Extend winding head 4. As a result, these rod conductors 6 are assigned to the same or different interconnection levels 5 and thus to certain interconnection webs 9 in order to implement a specific interconnection pattern.

FIG. 2 shows a side view of the stator from FIG. 1. The first

Winding head 3 has four interconnection levels 5 and second winding head 4 has four interconnection levels 5 and an interconnection level 7 with phase connection 8. The interconnection levels 5 and 7 are all arranged perpendicular to the central axis 23 of the stator 1, while the bar conductors 6 are arranged parallel to this axis. The central axis 23 describes the axis of a rotor (not shown) that can be inserted into the stator 1 and at the same time serves to determine the geometric properties of the elements of the stator 1, such as e.g.

Stator sheath 2, rod conductor 6, interconnection levels 5, etc., to describe and relate to each other.

FIGS. 3 and 4 show a winding head cooling for a stator from FIGS. 1 and 2 in a basic variant with an annular gap-shaped fluid inlet 25 and

annular gap fluid outlet 26.

3 shows a cross section through a stator 1 along the central axis 23, the stator 1 now shown additionally having a cylindrical cooling housing / sleeve 20 in comparison to FIGS. 1 and 2. The cooling housing 20 is in one piece and has a thread-shaped in its central outer section

Cooling fins 44, on which a cooling fluid such as water can flow, and on the two end sections on outer rings 28. The stator casing 2 lies against the inside of the cooling housing 20 and has essentially the same length as this

Section. The stator can be cooled indirectly, ie without direct fluid contact, via the cooling housing.

The winding head has direct cooling, i.e. a cooling fluid such as a dielectric oil can be passed through the winding head. The two

Winding heads 3 and 4 lie within the two outer rings 28 formed by the cooling housing. The winding heads 3 and 4 or their outermost interconnection level 5 are / are each protected from access to the housing 20 by an annular cover unit or cover ring 21 with an inner ring 22. The cover ring 21 forms with the outer ring 28 an annular gap 25, which acts as an inflow for a cooling fluid serves. The cover ring 21 forms together with the inner ring 22 an annular gap 26 which serves as a drain for a cooling fluid. Both winding heads 3 and 4 thus each have an annular cover 21 with an inner ring 22 as a cover for the interconnection levels 5 and 7 with respect to the outside. From the

The cross section of the stator 1 can be clearly seen that the rod conductors 6 and 6a are formed concentrically around the central axis 23 of the stator 1. The rod conductors 6 and 6a lie in pairs in the same grooves in the stator jacket 2. The rod conductors 6a arranged inside or closer to the axis 23 are longer in comparison to the rod conductors 6 arranged outside and preferably extend to the outermost interconnection levels of the winding heads 3 and 4 The housing 20 is at least partially made of metal in order to enable a better cooling effect for a cooling fluid and the other elements of the stator 1.

4A shows a section on the stator 1 according to section A-A from FIG. 3, the bar conductors 6, which are located between the inner ring 22 and the outer ring 28 and are connected in pairs via connecting webs, in particular being recognizable.

FIG. 4B schematically shows four ring-shaped areas or circular rings which result between the inner ring 22 and outer ring 28 of the stator according to FIGS. 3 and 4a. The ring areas are introduced for easy reference so that they can be referred to below. The inner and outer areas represent annular gaps 25, 26 for the inflow or outflow of the cooling fluid. The annular area 30 indicates the area in which the arcuate part of the connecting webs 9 runs. It can be used as a bridging area 30

be addressed. The ring area 29 shows the ring area in which the rod conductor 6; 6a are arranged in the stator slots and with the

Wiring webs 9 are connected. It can also be addressed as a groove area 29 or contact area 29.

Figures 5A, B and 6A, B are two different below

Variations of a winding head cooling according to Fig. 3 executed.

FIGS. 5A, 5B show a first exemplary embodiment of a winding head cooling with exclusively radially arranged partition walls 31. The winding consists of rod conductors 6, 6a, which are arranged in two layers in the grooves of a laminated core 2 (not shown in FIG. 6A) and via connecting webs arranged in multiple layers 9 (only shown in part). The connection webs 9 are attached by or in regularly over the circumference

Retaining bars / retaining clips 31a held. The retaining clips also form the radial partitions 31. The interconnection webs 9 of the individual interconnection levels 5 are - with the exception of the radially extending ones

Retaining clips - fluidically not separated horizontally.

The cooling fluid is introduced evenly through an annular gap 25 into the winding head over and over the entire height of the winding head, is deflected in the direction of the central axis 23 by means of the radial partition walls 31, and leaves the latter

Winding head then over the partially interrupted annular gap 26. The same connecting web sections are thereby exposed to approximately the same amount of coolant and thus approximately the same cooling.

5A shows a stator analogous to FIG. 3 with a section B-B according to FIG. 5B. with a partial cross section, on the one hand on a cover element 21 and on the other hand on the vertically arranged partition walls 31 of the cooling channel. On the top of the cooling channel, the cover unit 21 or

Lid arranged. The inner ring 22 and the outer ring 28 form the lateral boundaries of the cooling channel. Bearing against the inner ring 22 and the cover 21, the vertically arranged partition walls 31 are arranged in a radial manner. An annular gap 25 is formed between the cover ring 21 and the outer ring 28 as an inflow for a cooling fluid. An annular gap 26 is formed as a drain between the cover ring 21 and the inner ring 22, the inner annular gap 26 being interrupted by webs of the cover part 21. The partition walls 31 are designed radially and in particular axially symmetrically to the central axis 23. By means of the partition walls 31 and the cover 21 channels are formed, which are laminar

Allow fluid flows between the annular gap 25 and the annular gap 26.

FIG. 5B shows a cross section along the axis of the stator of FIG. 5A, which explains the view of and into the cooling channel. The cover ring 21 is arranged on the winding head or on its top interconnection level 5. The annular gap drain 26 is formed between the inner ring 22 and the cover ring 21. The annular gap inflow 25 is formed between the outer ring 28 and the cover ring 21. Corresponding arrows are on the left side of the

Cross-section drawn, which describe the flow flow. While in the 5A the vertical partitions 31 can be seen, the partitions arranged perpendicular to the central axis 23 are shown in FIG. 5B. In addition to the bar conductors 6 and 6a, the connection points with the connecting webs 9, at which the two elements are connected to one another, can be clearly seen.

FIGS. 6A and 6B show a second exemplary embodiment with cooling ducts of a winding head connected in parallel in a manner analogous to FIG. 3. The individual ones

Interconnection levels 5 are separated by horizontal insulation disks 32, on which the interconnection webs 9 are positioned. Within everyone

Interconnection level 5, the interconnection webs are combined into interconnection web groups 40, with individual interconnection web groups being separated from one another by radial partition walls 42. Through arcuate partitions 34,

35, a cooling fluid flowing in or flowing out via an annular gap 25 or 26 is brought to tracks along the longitudinal axis of the connecting web.

6A shows a plan view of the stator 1 according to FIG. 3 with a partial cross section (see section B-B in FIG. 6B), on the one hand

Cover element 21 as well as on an interconnection level

Interconnection webs 9 In addition, in this case, no radially formed partition walls 31 can be seen, but rather the arcuate inner walls and

Outer walls 34 and 35. On the left side, between the inner ring 22 and the cover element 21, radial elements or webs can be seen, which fasten the ring 22 and the cover 21 together and are arranged in the region of the annular gap drain 26. Between the inlet area 43 and the outlet areas

36 within the cooling channel, a split fluid flow forms between these walls. As can be seen from the top view of the stator 1, the connecting webs 9 are arranged in groups 40 of five, each in a ring sector, which are formed by radial partition walls 42. Of the

Inlet area 43 can be designed as a throttle element, advantageously as a bore in the outer wall 35, in order to achieve a uniform fluid distribution between the different groups 40.

FIG. 6B shows a cross section along the axis of the stator 1 from FIG. 6A, which explains the view of and into the cooling channel. Again, the rod conductors 6 and 6A can be seen, which are connected to the connecting webs 9. A fluid flow is also shown on the left-hand side, which flows through from the annular gap inflow 25 the cooling channel flows to the annular gap drain 26. The cooling channel itself is ring-shaped and is essentially formed by the cover ring 21, the inner ring 22, the outer ring 28 and the lowest insulation ring 32.

7 and 8 show a configuration option for the groove area 29 of an embodiment according to the invention for a stator 1, in which radial partition walls of a cooling duct according to the invention are formed only in the groove area 29. The design of the fluid channel in the area of

Bridging area is subject to change.

FIG. 7 shows a top view of a stator 1 with housing 20 and outer ring 28 and inner ring 22, but without a rod conductor. Analogous to the previous examples, connecting webs 9 for forming a composite winding are arranged in the end region of the stator laminated core 2. Radial partitions 31 are integrally formed with the inner ring.

8A and 8B show perspective views of a cover unit 21, for a winding head of a stator, with an integrally connected inner ring 22, radially arranged partition walls 31 and annular gap drain 26. The cover unit has an annular projection with an O-ring. When assembled, the projection separates the inflow area from the outflow area, cf. Fig. 13.

Figures 9 to 11 show an embodiment of the

Bridging area 30 of an embodiment according to the invention. Individual interconnection webs 9 are received in insulation disks or insulation rings 32 and separated from one another by arcuate partition walls 41 in such a way that a well-defined cooling channel is formed for each individual interconnection web 9. This means that a comparable cooling capacity can be guaranteed for each connection web.

9A shows an exploded view of an insulation ring 32 of a cooling channel with an interconnection level 5 of three

Interconnection web groups 40, each with five interconnection webs 9, which in particular on the insulation ring 32 or the horizontal partition wall 32

prefabricated grooves or recesses can be arranged. The insulation ring 32 has three fluid inlets 38, that is to say a separate one for each connecting web group Inlet, as well as two fluid outlets 39 for each connecting web 9, ie ten outlets per connecting web group 40 and thirty outlets 39 for the insulation ring 32. All outlets 39 are directed towards the center of the ring 32.

So that the interconnection webs 9 are arranged appropriately in the respective interconnection web group 40, intermediate walls 41 are between the

Connection webs 9 or formed on the insulation ring 32, which form the aforementioned grooves. In addition, the interconnection web groups 40 are separated from one another by radial partition walls 42. As a result, a fluid flow can be divided into parallel partial flows for each interconnection land group and, in addition, each partial flow into further parallel partial flows for one each

Half of the connecting web.

FIG. 9B shows a plan view of the insulation ring 32 shown in FIG. 9A. In this figure, no connecting webs 9 are arranged in order to better show the channels or grooves which are formed by the intermediate walls 41. Each groove is connected to the outside through a triangular inlet extending from the inlet region 38 to an inner wall 34 and can thus be supplied with a cooling fluid. The cooling fluid flowing in through an inlet area 38 can flow out of ten different outlets 39 in the direction of the central axis 23. This applies to each ring sector of a ring 32 or each interconnection web group 40 of an interconnection level 5. Instead of a continuous inlet area 38, however, the intermediate walls 41 and the outer wall 35 can also not be interrupted and each have a radial bore as a fluid inlet. By designing the bore, a pressure drop across each inlet area can be set, e.g.

100 mbar over the outer wall and lOmbar over each partition.

Particularly when the stator is in a lying position, this can result in a

Uneven distribution of cooling fluid over a plurality of interconnection land groups 40 and / or a plurality of interconnection levels 5 can be achieved.

10A and 10B each show perspective views of assembled insulation rings 32 from a cooling duct without connecting webs. The four insulation rings 32 arranged one on top of the other each have three inlets 38 and thirty outlets 39. 11 shows the assembled insulation rings 32 according to FIGS. 10A and 10B with connecting webs 9.

Finally, FIGS. 12A and 12B show a combination of the design options shown in FIGS. 9 to 11 and 7 to 8. The assembled insulation rings 32 according to FIGS. 10A and 10B are provided with a cover unit or cover 21 analogous to FIG. 8. The lid unit 21 is equipped with an inner ring 22 and vertical partitions 31. The connection bars used cannot be seen in these two cases.

Figures 13 to 15 show a preferred embodiment for a

Stator cooling with a cooling duct according to the invention.

13 shows a perspective view of a stator 1 with a cooling channel according to the present invention and with the fluid flows shown. The stator 1 has a cooling housing 20 and cooling fins or a turn 44

educated. On the upper side, the cover unit 21 with the inner ring 22 can be seen, which in connection with the outer ring of the cooling housing 20

Form annular gap inflow 25 and annular gap outflow 26.

14 shows a longitudinal section through an upper part of a stator 1, in particular its winding head with a cooling duct according to the invention, with fluid flows being shown on the right-hand side. In comparison to the stators described above, this exemplary embodiment is equipped with a fluid housing 48. The fluid housing 48 has a cylindrical outer wall 50 and an annular cover 51, for example a bearing plate. The outer wall 50 bears directly against the cooling housing 20. The cover 51 is fastened to the outer wall 50 and has a plurality of openings for a fluid inflow and an opening for a fluid outflow as well as for a rotor. Of the

Fluid inflow is directed onto the cover unit 21 and presses it downwards or onto the stator jacket 2. The cover unit 21 is axially displaceably mounted. The lid unit separates the inflow and outflow areas by means of an annular projection with a framed O-ring. By adjusting the flow resistance for the cooling fluid in large areas by designing the individual inflows and fluid passages, in particular in the inflow to connection web groups, a contact pressure of the cover unit can be adjusted be, for example in a range of 150 to 250 mbar. By means of the enlarged cross-section along the longitudinal axis or central axis 23 of the stator 1, the stator casing 2 with the bar conductors 6 and 6a, as well as the winding head with the various connecting webs 9, insulation rings 32 of the cover unit 21 with the inner ring 22 and the annular gaps formed thereby for inflow and drain 25 and 26 clearly visible. The webs 9 and the conductors 6, 6a are fastened to one another at the contact points 33, in particular welded.

Overall, this results in a fluid flow connected several times in parallel. The individual interconnection levels are fluidically connected in parallel due to the inflow of the annular gap. Through the insulation washers are the individual

Wiring webs or half webs connected fluidically in parallel.

15 shows an exploded view of a stator 1 according to the invention with two winding heads 3 and 4 and cooling channels. The stator 1 is with a

Stator sheath 2 equipped, in the inside grooves or

Groove region 29, the rod conductors 6 and 6a are arranged concentrically around the central axis 23. The winding head 3 is arranged on one side in order to connect the rod conductors 6 and 6a at one end to the corresponding connecting webs 9. On the other side of the stator shell 2 is the other

Arranged winding head 4, which differs from the first winding head 3 in that it has an additional interconnection level 7 with a

Has phase connection 8. Both winding heads 3 and 4 are arranged one above the other with a sealing mat 45, an adapter piece 47, four interconnection levels 5 with the corresponding interconnection webs 9 or with three interconnection web groups 40. Finally, a cover element 21 is provided, which has an inner ring 22 and vertical radial partition walls 31.

16 shows four different construction variations of the insulation rings 32, in particular their intermediate walls 41, within a cooling channel with interconnection webs 9 arranged therein. The intermediate walls 41 and

Insulation rings 32 can have holding elements 46 in the form of knobs or the like. In example a), the elements 46 are formed on the intermediate walls 41. In example b) the elements 46 are arranged on an intermediate wall 41 and on the underside of a ring 32. In example c) the elements 46 are simultaneously on the underside of the upper ring 32 and on the underside of the same upper ring 32 formed. Example d) are the elements 46 on both

Partitions and top and bottom of the top and bottom

Isolation ring 32 formed, the side elements 46 and the

Ceiling / floor elements 46 not at the same height, but along the

Longitudinal axis of the connecting web 9 are alternately formed, cf. Fig. 17.

FIG. 17 shows, schematically and in detail, a connection web 9 held between two partition walls 41. The connection web is held by mutually arranged knobs 46. The knobs 46 make it possible to mount the connecting web 9, in which it is subjected to bending and is clamped.

FIG. 18 shows a variant of a stator according to the invention in a plan view with a cover part 17 with an enlarged inflow opening 25 '. The expanded inflow opening 25 ′ is designed as a recess on the cover 21. The

Inflow opening 25 'is attached to the top of the stator, the stator being operated in a lying arrangement. Gravity acts in the

Drawing level accordingly from top to bottom. As a result, a uniform fluid supply can be achieved over the entire circumference of the stator. In particular, the flow resistance in the inlet in the upper area of the winding head can be reduced. This can result in an uneven distribution of fluids, as occurs as a result of an in the antechamber of the end winding (between cover 21

Housing cover 51, cf. Fig. 14) accumulating fluid, and the uneven pressure distribution resulting from the hydrostatic pressure can be avoided or reduced. As a result, uniform cooling of the entire winding overhang can advantageously be achieved even at very low pressures and / or at a very low volume flow.

With only a low fluid pressure, the fluid first collects at the lowest point in the anteroom. There it can because of the high flow resistance of the

Do not drain the annular gap as quickly as it is fed. The fluid level in the anteroom rises accordingly up to the level of the enlarged inflow opening 25 '. From there it can be practically without flow resistance in the

penetrate the annular gap 25 behind it, where it flows evenly along, for example, the outer circumference of insulation disks 32 and through individual inlet openings 38 to interconnection web groups 40 or interconnection webs 9 flows, cf. Fig. 12b. The fluid inflow to the anteroom can be attached at any point.

Reference symbol list

1 stator

2 stator jacket or stator laminated core

3 end winding side A

4 end winding side B

5 interconnection level

6 rod ladders

6a rod ladder

7 interconnection level with phase connection

8 phase connection

9 connection bars / end connectors

20 cooling housing / sleeve

21 lid

22 inner ring

23 central axis

25 Inflow annular gap

25 'enlarged inlet opening

26 Annular gap drain

28 outer ring

29 Groove area / connection area

30 bridging area

31 partition, vertical

32 partition, horizontal or insulation ring / washer

33 Contact / welding of rod conductors with connecting web

34 partition, arched inner wall

35 partition, arched outer wall

36 outlet areas

37 cover

38 inlet

39 outlet

40 interconnection bridge group

41 partitions Partition wall between interconnection web group inlet area

Swirl / cooling fins

Sealing mat

Studs / holding element

Adapter piece / ring

Fluid housing

Outer wall of the fluid housing

Cover of the fluid housing

Claims

Expectations

1. Cooling channel for a winding head of an electrical machine, the cooling channel for guiding a cooling fluid with at least one inflow (25) and at least one outflow (26) and for arrangement around the

Winding head is annular,

That means that

the cooling channel has a plurality of partition walls (31; 32; 41; 42) which are arranged such that parallel subchannels are formed between the at least one inflow (25) and the at least one outflow (26), the inflow (25) radially outside, with respect to the cooling channel, and the outflow (26) are arranged radially inside or the inflow is arranged radially inside and the outflow is arranged radially outside.

2. Cooling duct according to claim 1,

That means that

the inflow (25) and / or the outflow (26) are designed as an annular gap, the inflow and the outflow being separated from one another by an annular ceiling section (21) of the cooling channel.

3. Cooling channel according to claim 1 or 2,

That means that

at least a part of the plurality of partitions are arranged in a radial shape and form radial partitions (31).

4. Cooling duct according to one of claims 1 to 3,

That means that

at least a part of the plurality of partition walls are designed in the shape of a circular arc (34; 35; 41) and in particular are arranged concentrically to one another in groups.

5. Cooling duct according to one of claims 1 to 4,

That means that

has at least a part of the plurality of partition walls concentrically and parallel to each other arranged insulation rings (32).

6. cooling channel according to claim 4 and 5,

That means that

the radial partitions (31) and the insulation rings (32) are arranged perpendicular to each other.

7. Cooling duct according to one of claims 1 to 6,

That means that

the partitions have fastening elements (46), in particular clamping elements or knobs.

8. Cooling duct according to one of claims 1 to 7,

That means that

the plurality of partitions are formed from an elastic material.

9. Cooling duct according to one of claims 1 to 8,

That means that

the cooling channel is constructed in several parts.

10. cooling channel according to claim 9,

That means that

the cooling duct has a sealing element (45) as the base component and a stator cooling housing (20) as the outer side wall.

11. stator (1), in particular for an electric motor, with a plurality of rod conductors (6, 6a), the stator (1) having at least one cooling duct according to one of the preceding claims and the partition walls (31; 32) of the cooling duct between at least some of the rod conductors (6, 6a) are arranged.

12. stator (1) according to claim 11,

That means that

the stator (1) has a plurality of connecting webs (9) corresponding to the bar conductors (6, 6a).

13. Electrical machine with a cooling channel according to one of claims 1 to 9 or a stator (1) according to claim 10 or 11.