DE102019202566A1 - Rotor for an electrical machine with cooling channels - Google Patents

Abstract

A rotor (1) for an electrical machine with a rotor carrier (2) and a laminated core (5) arranged on this is described, the rotor carrier (2) having a first carrier part (3) with a rotating axis (A ) of the rotor (1) comprises axially extending cylinder section (3a) for the arrangement of the laminated core (5). The laminated core (5) is fixed between a first axial stop (6a) and a second axial stop (6b) and at the end of the laminated core 5 (5) are radial channels running at least in sections in the radial direction in the area of one of the axial stops (6a, 6b) (15a, b) provided. It is proposed that the radial channels (15a, b) are formed between the laminated core (5) and one of the axial stops (6a, 6b).

Description

The invention relates to a rotor for an electrical machine with cooling channels formed therein.

A generic rotor, which according to an application can represent a component of an electrical machine of an electric or hybrid vehicle, is for example with the DE 11 2011 101 540 T5 known. The rotor arm of the rotor that runs inside the stator there comprises an axially extending cylinder section for the arrangement of a laminated core, with several axially extending cooling channels distributed around the circumference for a cooling fluid being formed between an inner circumferential surface of the laminated core and an outer circumferential surface of the cylinder section to dissipate heat loss are. On a first axial end face, the cylinder section is followed by a radial section which directly forms an axial stop for the laminated core directly on the radially inner area of the laminated core and indirectly on an adjoining radially outer area of the laminated core with the interposition of a first annular disk. A further, second annular disk rests on the opposite, second end face of the laminated core over the entire radial extent of the laminated core. Starting from the aforementioned axial cooling ducts, cooling ducts leading radially outwardly on the first end face within the radial section and on the second end face within the annular disk branch off, which open into exit openings opposite the radial and end winding areas on the stator. These radial cooling channels are completely formed in the material of the radial section or the annular disk. The cooling channels run on both end faces at an axial distance from the laminated core of the rotor and therefore, when there is a stator laminated core of approximately the same length axially, only hit the winding heads located there in an area that is also axially spaced from the end faces of this stator laminated core.

On the basis of the prior art mentioned, the invention has the object of further improving a rotor of the type mentioned at the beginning. In particular, a rotor with improved cooling of the laminated rotor core is to be created. In addition, the rotor should be designed in such a way that it also enables improved cooling of a stator with a laminated core of essentially the same length as the rotor and with a stator winding.

The above-mentioned object is achieved by a rotor with the features specified in claim 1. Advantageous configurations and developments of the invention can be found in the dependent claims and in the following description of the figures.

A rotor for an electrical machine with a rotor carrier and a laminated core arranged thereon is therefore proposed, the rotor carrier comprising a first carrier part with a cylinder section which extends axially with respect to an axis of rotation of the rotor for arranging the laminated core. The laminated core is fixed between a first axial stop and a second axial stop, and radial channels extending at least in sections in the radial direction are provided on the face of the laminated core for guiding a cooling fluid in the area of one of the axial stops. In the context of the invention it is proposed to form the radial channels between the laminated core and one of the axial stops.

The radial channels running directly on the laminated core have the advantage that a cooling fluid guided therein is in direct heat transfer contact with the laminated core, i.e. the source of the heat loss of an electrical machine, thus enabling effective heat exchange. In addition, a stator radially opposite the rotor, the laminated core of which usually has an axial extent comparable to and substantially corresponding to the laminated core of the rotor, can be acted upon with a cooling fluid axially closer to the laminated core. A winding fixed on the stator can be covered by the cooling fluid in a larger area in the area of the winding heads projecting axially beyond the laminated core. Thus, the stator and the electrical machine as a whole can also be cooled better.

The rotor can in principle be designed and provided for an electrical internal rotor motor or for an electrical external rotor motor. An axial stop can be formed in one piece on the rotor arm, in particular on the cylinder section, or can be formed by an element that is separate from the cylinder section.

According to one embodiment of the invention, it is proposed to design the rotor arm in several parts, this comprising a second carrier part with a radial section and the first carrier part being firmly connected to one another by means of the cylinder section and the second carrier part by means of the radial section at a mutual connection area. In particular, it is provided that the first axial stop is formed on the first carrier part and the second axial stop is formed on the second carrier part and the second axial stop is formed by the radial section of the second carrier part and is arranged radially to the connection area.

The cylinder section formed on the first carrier part can be designed to form a rotor for an electrical internal rotor machine with a radially outer joining surface, the first and second axial stops being located radially outside the cylinder section and the connecting area of the carrier parts. In a rotor for an electrical external rotor machine, these axial stops are arranged radially on the inside to a joining surface formed radially on the inside on the cylinder section, with no separate ones on the second support part due to the radial section already present there and usually running inward, in particular for connection to a rotor shaft or rotor hub Measures are to be provided.

According to an advantageous embodiment, the first axial stop can be formed by a radial section adjoining the cylinder section. This stop can in particular be designed as an angled or bent section with respect to the cylinder section and, if necessary, extend radially over the entire laminated core. The stop can thus be formed on a radial position that is significantly different from the cylinder section and a joining surface of the laminated core. In the case of a diameter step formed on the cylinder section and serving as an axial stop, this usually coincides essentially with a radially inner or outer boundary of the laminated core, depending on the design of the electrical machine. As a result, a laminated core is clamped radially on one side and, as a result, the radially opposite surface of the laminated core tends to fan out the individual laminations. In contrast, the radial section in the proposed solution can extend well within the radial extent of the laminated core, in particular at least up to a third, up to half or even more, so that an axial fanning out of the laminated core can thus be effectively avoided.

According to a further development, it is provided that an axial stop is designed as a contact area that protrudes axially from a base body to the laminated core, that is, an axial projection. Such an axial projection thus has a smaller radial extent in comparison to the entire radial section. In this way, a reduction in the effective area resting on the laminated core and an increase in the axial contact pressure are produced, which leads to better cohesion of the laminated core, in particular under thermal shock loads and at high speeds of the rotor. Such an axial projection can be represented, for example, by an intermediate element, by machining or by reshaping the carrier parts at their radial sections. In this way, an axial gap can be generated on one or both end faces of the laminated core outside of these axial projections to the rotor arm, which can extend radially inwards and / or outwards on the axial projection.

In principle, such an axial projection on the rotor arm can be closed in the circumferential direction or formed with an opening area. According to an advantageous embodiment, however, a plurality of axial projections can also be provided in the circumferential direction, which are separated from one another by intermediate spaces and the radial channels are formed between two axial projections in each case. The laminated rotor core thus rests axially on the rotor arm only in areas at individual positions, in particular at points or in the form of a stamp. The radial channels between the axial stops and the laminated core are thus created by the spaces created in the radial and axial directions. In this way, cooling channels or cooling spaces are formed through which a cooling fluid can flow in order to dissipate heat loss from the laminated rotor core.

For the mutual connection of the carrier parts, the first carrier part and the second carrier part can be in engagement by means of an axial plug connection, in particular by means of an axial plug-in toothing. For this purpose, several axial tabs or teeth spaced from one another in the circumferential direction and recesses or gaps located between these in the manner of an axial toothing can be formed on the end face of the first carrier part opposite the radial section, i.e. on or adjacent to the cylinder section. At the same time, openings can be formed on the radial section of the second carrier part which correspond to the teeth mentioned and can be brought into engagement with them.

Furthermore, the rotor arm can have radial passages on its cylinder section, which are in fluid connection with the radial channels in the presence of a cooling fluid. A cooling fluid can thus pass unhindered through these passages from a radially inner to a radially outer side of the rotor arm and absorb and dissipate heat loss due to the direct contact with the laminated core. The radial passages can advantageously be provided on the rotor arm at a front end region of the laminated core or else at any other position.

For example, first radial passages can be formed on the cylinder section of the first support part axially approximately in the region of the first axial stop, and second radial passages can also be formed on the axially opposite side. The second radial Passages can preferably be provided in the area of the axial side of the second carrier part facing the laminated core. According to one embodiment variant, the second radial passages can be formed at least partially by openings which, in the assembled state, remain between the two carrier parts in the area of the gaps in the toothed profile.

In a further advantageous embodiment of the rotor, the radial passages can be aligned with the radial channels present in the area of the axial stops, so that an unimpeded passage of a cooling fluid through the rotor arm and laterally past the laminated core is made possible. In particular, the explained axial projections and the gaps of the toothed profile on the rotor arm are arranged offset to one another in the circumferential direction.

The laminated core can be fixed on the rotor arm by a joint connection, for example by shrinking it on. To increase the torque strength, however, it can be advantageous to form a radial positive connection between the first carrier part and the laminated core. For this purpose, corresponding tooth-shaped and corresponding groove-shaped structures, for example in the form of radial teeth or the like, can be formed on the cylinder section of the first carrier part and on the joining surface of the laminated core.

To further improve the heat dissipation from the laminated core, axial channels can be provided radially between the rotor arm and the laminated core, the axial channels opening into the radial channels explained and being in fluid connection therewith in the presence of a cooling fluid. The axial channels can in particular be present or serve at the same time as elements of the previously explained radial form-fit connection between the rotor carrier and the laminated core. The radial form-fit connection can be made permeable in the axial direction for guiding a cooling fluid. For this purpose, a plurality of axially extending recesses, in particular grooves, which are distributed in the circumferential direction and in which radially flared projections, in particular teeth, can engage on the cylinder section, can be formed on the joining surface of the laminated core. It is not necessary here for the projections on the first carrier part to be formed over the entire axial extent of the cylinder section. Rather, it is sufficient if a projection only extends over a fraction, in particular approximately between a quarter, a third or a half, of the axial extent of the cylinder section. On the circumference of the rotor arm, adjacent projections can be arranged axially staggered on the cylinder section. In particular, the laminated core can comprise two sub-assemblies, at least some of the projections being able to overlap a mutual connecting area of the sub-assemblies. Other projections can only engage one sub-package at a time.

The axially staggered arrangement of several axial projections on the circumference of the rotor, which can be made axially shorter than the laminated core, enables a centered and non-rotatable arrangement of the rotor on the rotor arm. On the other hand, the grooves cooperating with the axial projections on the laminated core can act as cooling fluid channels over their entire axial length. As a result of the short engagement length of the form-fit connection, which is comparatively short compared to the axial extension of the laminated core, the laminated core can be cooled directly over larger areas, that is to say without prior heat dissipation via or through the rotor arm. Furthermore, an annular segment space between the joining surface of the first carrier part and the joining surface of the laminated core, through which a cooling fluid can also flow, can be represented in a circumferential area between two axially running grooves. In this case, the laminated core is only held in sections by the form-fitting connection on the rotor arm.

In terms of manufacturing technology, the rotor arm can comprise a formed sheet metal part on which one of the axial stops is formed. Furthermore, in the case of a multi-part rotor arm, the first and the second carrier part can be designed in a cost-effective and weight-optimized lightweight construction by means of formed sheet metal parts and, after joining, they can be welded to one another to secure the mutual connection. For this purpose, in particular in the area of the plug connection, several welding areas can be provided on the axial inside and / or outside. The welding can take place in areas, in particular at points and essentially sequentially, with the process heat introduced essentially not causing any distortion of the rotor. Subsequent tempering of the rotor and / or reworking are not required.

The invention further relates to an electrical machine with a rotor as described above and with a stator with a stator winding arranged radially with respect to the rotor.

The invention is explained by way of example below with reference to an embodiment shown in the figures.

• 1 einen Rotor mit einem zweiteiligen Rotorträger und einem Blechpaket in einer Axialschnittdarstellung,
• 2 ein erstes Trägerteil des Rotors von 1 in zwei Ansichten,
• 3 ein zweites Trägerteil des Rotors von 1 in zwei Ansichten;
• 4 eine stirnseitige Ansicht eines Blechpakets.

Show it:

• 1 a rotor with a two-part rotor arm and a laminated core in an axial section,
• 2 a first support part of the rotor of 1 in two views,
• 3 a second support part of the rotor of 1 in two views;
• 4th an end view of a laminated core.

1 shows a rotor 1 for an electrical machine with a multi-part rotor arm 2 and a laminated core arranged on this 5 . The rotor 1 is in the present case designed as a functional part of an electrical machine designed in internal rotor design, in particular a permanently excited synchronous machine, which is provided as a drive unit of a hybrid or electric vehicle. The electrical machine further comprises a stator, not shown in the drawing, with a stator winding, which in the usual manner forms an air gap radially to the rotor 1 is arranged.

The sheet metal package 5 of the rotor 1 is made in a known manner from axially stacked sheet metal lamellas and has pockets, not visible in the figures, in which permanent magnets are arranged. The rotor arm 2 initially comprises a first carrier part 3 with one referring to an axis of rotation A. of the rotor 1 axially extending cylinder section 3a for the arrangement of the laminated core 5 . To produce a rotary drive connection of the rotor 1 with further drive train components and for bearing the rotor 1 is a second support part 4th provided, which initially has a radial section 4a includes. The support parts 3 , 4th are formed from a comparatively thin-walled, but preferably high-strength sheet steel as shaped sheet metal parts and are, as will be explained in the course of the further description, by means of the cylinder section 3a and by means of the radial section 4a at a mutual connection area 9 firmly connected. The sheet metal package 5 is on a joining surface 3c of the cylinder section 3a received and between one on the first carrier part 3 provided first axial stop 6a and one on the second support part 4th trained second axial stop 6b set. The second axial stop is here 6b through the radial section 4a formed and radial to the connection area 9 arranged.

In the exemplary embodiment, both are axial stops 6a , 6b radially outside of the cylinder section 3a and the connection area 9 arranged. As can be seen in the figures, the first axial stop is 6a by a material to the cylinder section 3a subsequent and angled radial section there 3b educated. The cylinder section 3a and the radial section 3b are made in one piece. These stops are thus on one opposite the cylinder section 3a or a joining surface located there 5a of the laminated core 5 clearly different radial position formed.

They are specially designed to form the axial stops 6a , 6b on the carrier parts 3 , 4th several individual axial projections in the circumferential direction 10a ; 10b provided, which opposite one of the radial sections 3b , 4a protrude axially and which are in contact with the laminated core 5 are located and can exert an axial bias on this. The axial protrusions 10a ; 10b are produced by reshaping the carrier parts, in particular by pressing out sheet metal material. In this way, these axial projections are outside 10a , 10b on both ends of the laminated core to the rotor arm 2 each axial and on the laminated core 5 continuous radial spaces 14a , 14b like that in the 2 , 3 is recognizable. The rotor core 5 is therefore axially only at individual positions, in fact punctiform or stamped on the rotor arm 2 on. The axial protrusions 10a ; 10b are circumferentially arranged in such a way that they are preferably outside the magnet receiving pockets of the laminated core 5 , in particular rest radially inside to or between these magnet receiving pockets. The spaces in between 14a , b form on the laminated core 5 in the radial direction, at least in sections or through radial channels 15a , b from, which is used to dissipate heat loss from the laminated rotor core 5 can be flowed through by air or by a cooling fluid and which have radial outlet openings in the exemplary embodiment. On the electrical machine, these outlet openings are located radially opposite the winding heads of a laminated stator core. Alternatively, the outlet openings can also be formed axially.

For the mutual connection of the carrier parts 3 , 4th are on the radial section 3b opposite end face of the first carrier part 3 , i.e. on or adjacent to the cylinder section 3a a plurality of axial extensions or teeth spaced from one another in the circumferential direction 18th and recesses or gaps located between them 20th designed in the manner of an axial toothing or an axial toothing profile. At the same time are on the radial section 4a of the second carrier part 4th Access openings 22nd provided, which in their arrangement and dimensioning to the teeth 18th correspond to be in engagement and with these a plug connection 23 , especially in the form of a spline between the two carrier parts 3 , 4th form.

As can also be seen in the figures, the rotor arm 2 also radial passages 26a ; 26b which with the laminated core 5 adjoining spaces 14a , 14b are connected. Through these passages 26a , 26b a cooling fluid can thus pass through the rotor arm unhindered in the radial direction 2 pass through and through direct contact with the laminated core 5 absorb and dissipate heat loss. The radial passages 26a , 26b are present on the rotor arm 2 at both face end areas of the laminated core 5 intended. In particular, are on the cylinder section 3a of the first carrier part 3 axially approximately in the area of the first axial stop 6a first radial passages 26a and second radial passages on the axially opposite side 26b educated. The passages 26b are thus in the area of the laminated core 5 facing axial side of the second carrier part 4th intended. In 1 can also be seen that the passages 26b through opening areas 20 ' are formed, which in the assembled state between the two support parts 3 , 4th in the area of the recesses 20th the tooth profile of the connector 23 remain.

The radial passages 26a , 26b are arranged in such a way that they correspond to the in the area of the axial projections 10a , 10b existing spaces 14a , b , in particular radially aligned, so that an unhindered passage of a cooling fluid through the rotor arm 2 and on the side of the laminated core 5 is made possible. The axial projections are particularly useful for this purpose 10a , 10b the axial stops 6a , 6b to the passages 26a , b and thus also to the recesses 20th of the tooth profile on the rotor arm 2 arranged offset to one another in the circumferential direction. In the 1-3 are directions of propagation of a cooling fluid on the carrier parts 3 and 4th in radial and circumferential direction with arrows ( F. ) indicated.

Coming back to the sheet metal package 5 is this on the rotor arm 2 fixed by a joint connection by axial plugging. To increase the torque strength is between the first carrier part 3 and the laminated core 5 a radial interlocking connection 28 , in particular designed in the form of radial teeth. At the joint surface 5a of the laminated core 5 are for this purpose a plurality of axially extending recesses, in particular grooves, distributed in the circumferential direction 5d formed in which on the cylinder portion 3a radially flared projections 3d intervention. A projection extends here 3d in each case only over a part, in particular approximately between a third and a half of the axial extent of the cylinder section 3a . On the circumference of the rotor arm 2 adjacent protrusions 3d are also axially staggered on the cylinder section 3a arranged. In the exemplary embodiment, the laminated core comprises 5 two sub-packages 5b , 5c , at least part of the protrusions 3d a mutual connection area of the sub-packages 5b , 5c overlaps. Other ledges 3d only apply to one partial package 5b , 5c a.

To further improve the heat dissipation from the laminated core 5 are radial between the rotor arm 2 and the laminated core 5 several axial channels distributed around the circumference 30th provided, which in the presence of a cooling fluid with the radial passages 26a , 26b are in fluid communication. In the exemplary embodiment explained here, the axial channels 30th through the grooves 5d of the laminated core 5 , so by elements of the aforementioned radial form-fit connection 28 educated. The form-fit connection 28 can be made permeable in the axial direction for guiding a cooling fluid, for example by the interacting profiles of the rotor arm 2 and the laminated core 5 do not touch the entire surface, but merely abut against one another in points or lines and / or, for example, by the teeth or projections 3d on the cylinder section 3a are designed to be axially open on both sides and thus permeable.

In another embodiment of the rotor 1 are on both support parts 3 , 4th Balancing areas 32a , b provided, which in particular as attached to one of the radial sections 3b , 4a subsequent ring areas are formed. At these balancing areas 32a , b can when balancing the rotor 1 Balance weights and / or balancing openings are attached or introduced.

The rotor arm 2 further comprises a rotor hub 34 with a hollow cylindrical shaft section 36 and with a radial flange formed thereon 38 , with which the second carrier part 4th connected is. For this purpose, the has the radial flange 38 a centering surface 38a and an axial stop 38b on. As can also be seen, the second carrier part is 4th at an axial end region of the first carrier part 3 and thus also at an axial end area of the rotor 1 arranged. The rotor 1 can be seen by means of the second support part 4th designed for easy storage. The second support part 4th further has two angled areas 4d , 4e on, being to the radial section 4a another radial section 4b and a tubular cylinder portion disposed therebetween 4c is provided. This can further stiffen and increase the load-bearing capacity of the rotor 1 be achieved.

When assembling the rotor 1 becomes the laminated core 5 until it rests on the axial projections 10a on the carrier part 3 postponed. The carrier part 4th is until it rests on the axial projections 10b with its access openings 22nd on the teeth 18th of the carrier part 3 introduced and held there under a bias by means of a pressing force. When joining the carrier parts together 3 , 4th an adjustment in the radial direction and a compensation of length tolerances in the axial position can take place at the same time. To secure the mutual connection are the carrier parts 3 , 4th in the area the connector 23 on the axial inside and / or outside by means of several welding areas 24 welded together. In the assembled state of the laminated core 5 on the carrier part 3 can be used to form the second axial stop 6b This eliminates the need for shock loads and plastic material deformation, which can damage the laminated core.

List of reference symbols

1

rotor

2

Rotor arm

3

first carrier part

3a

Cylinder section

3b

Radial section

3c

Joining surface

3d

head Start

4th

second support part

4a, b

Radial section

4c

Cylinder section

4d, e

Angulation

5

Laminated core

5a

Joining surface

5b, c

Partial package

5d

Groove

6a, b

Axial stop

9

Connection area

10a, b

Axial projection

14a, b

Space

15a, b

Radial channel

18th

tooth

20th

gap

20 '

Opening range

22nd

Access opening

23

Connector

24

Welding area

26a, b

Passage

28

Form-fit connection

30th

Axial channel

32a, b

Balancing range

34

Rotor hub

36

Shaft section

38

Radial flange

38a

Centering surface

38b

attack

A.

Axis of rotation

F.

Cooling fluid propagation direction

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 112011101540 T5 [0002]

Claims (12)

Rotor (1) for an electrical machine with - a rotor carrier (2) and a laminated core (5) arranged on this, wherein - the rotor carrier (2) has a first carrier part (3) with a rotating axis (A) of the Rotor (1) comprises axially extending cylinder section (3a) for the arrangement of the laminated core (5) and wherein - the laminated core (5) is fixed between a first axial stop (6a) and a second axial stop (6b) and wherein - the end face to the laminated core (5 ) in the area of one of the axial stops (6a, 6b) radial channels (15a, b) running at least in sections in the radial direction are provided, characterized in that the radial channels (15a, b) between the laminated core (5) and one of the axial stops (6a , 6b) are formed. Rotor (1) Claim 1 , characterized in that the rotor arm (2) comprises - a second carrier part (4) with a radial section (4a), wherein - the first carrier part (3) by means of the cylinder section (3a) and the second carrier part (4) by means of the radial section ( 4a) are firmly connected to one another at a mutual connecting area (9), and wherein - the first axial stop (6a) is formed on the first support part (3) and the second axial stop (6b) is formed on the second support part (4), wherein - the second axial stop (6b) is formed by the radial section (4a) and is arranged radially to the connecting area (9). Rotor after Claim 1 or 2 , characterized in that the first axial stop (6a) is formed by a radial section (3b) adjoining the cylinder section (3a). Rotor after one of the Claims 1 to 3 , characterized in that an axial stop (6a, 6b) has an axial projection (10a; 10b) protruding from a base body of the axial stop (6a, 6b) to the laminated core (5). Rotor after Claim 4 , characterized in that a plurality of axial projections (10a; 10b) are provided in the circumferential direction, which are separated from one another by spaces (14a; 14b) and wherein the radial channels (15a, b) are formed between two axial projections (10a; 10b). Rotor after one of the Claims 2 to 5 , characterized in that the first carrier part (3) and the second carrier part (4) are in engagement by means of an axial plug connection (22), in particular by means of an axial spline. Rotor after one of the Claims 1 to 6th , characterized in that the rotor arm (2) has radial passages (26a; 26b) on its cylinder section (3a) which are in fluid connection with the radial channels (15a, b) in the presence of a cooling fluid. Rotor after one of the Claims 1 to 7th , characterized in that a radial interlocking connection (28) is formed between the first carrier part (3) and the laminated core (5). Rotor after one of the Claims 1 to 8th , characterized in that axial channels (30) are formed radially between the rotor carrier (2) and the laminated core (5), the axial channels (30) opening into the radial channels (15a, b). Rotor after one of the Claims 1 to 9 , characterized in that the rotor arm (2) comprises a formed sheet metal part on which an axial stop (6a, 6b) is formed. Rotor after one of the Claims 1 to 10 , characterized in that the carrier parts (3, 4) are designed as formed sheet metal parts and are welded together. Electrical machine with a stator with a stator winding and with one according to one of the Claims 1 to 11 formed and arranged radially to the stator rotor.

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