DE102021211303A1 - Device for distributing cooling medium in a winding overhang of an electrical machine - Google Patents

Abstract

In order to provide a device (100) for supplying a cooling medium during rotation in an end winding (301) of a stator (300) of an electrical machine, which improves the cooling medium distribution in an electrical machine and increases the efficiency of the electrical machine, a device (100) proposed having a ring body (10), wherein the ring body (10) has a peripheral outer wall (14), and wherein at least one through opening (13) and/or a notch (17) is arranged in the peripheral outer wall (14).

Description

The invention relates to a device for supplying a cooling medium during rotation in a winding overhang of a stator of an electrical machine and an electrical machine having such a device.

In order to dissipate heat generated during operation of an electrical machine, in particular in the winding overhang of the stator, concepts are known in the prior art in which a cooling medium is fed into the electrical machine via cooling medium supply lines provided for this purpose and is fed through openings, in particular into an area of the winding overhang becomes.

From the DE 10 2017 201 390 A1 a rotor for an electrical machine is known, comprising one or more cooling channels through which a cooling medium can flow, which are connected to an annular space on an end face of the stator.

The DE 10 2017 214 560 A1 discloses an electrical machine with a hollow-cylindrical rotor shaft and radial bores for medium transport, in particular for coolant.

In the DE 2017 202 752 A1 is a rotor for an electrical machine with fan heads, from which cooling medium is discharged from a shaft cooling channel by suction when the rotor rotates.

The DE 10 2015 223 631 A1 discloses a constructed hollow rotor shaft with a spherically designed cooling medium distribution element.

Disadvantages of the concepts known from the prior art are, on the one hand, a partially inadequate distribution of coolant in the end winding and a potential entry of cooling medium into the air gap of the electric machine, which reduces the efficiency of the electric machine.

The object of the invention is to improve the cooling medium distribution in an electrical machine and to increase the efficiency of the electrical machine.

This object is achieved by a device for supplying a cooling medium during rotation in a winding overhang of a stator of an electrical machine, having a ring body, wherein the ring body has a peripheral outer wall, and wherein at least one through opening and/or a notch is arranged in the peripheral outer wall .

The device is preferably arranged on a rotor, in particular on a rotor end area, in the area of the end winding of the stator. The device is preferably arranged on the rotor and fastened to it in such a way that a central longitudinal axis running through the ring body coincides with the axis of rotation of the rotor.

The cooling medium is preferably a cooling liquid. The cooling medium is preferably a cooling oil.

The device is preferably fastened to the rotor, in particular to a rotor carrier, by means of a holding device, in particular by means of a holding ring.

The device is connected to the rotor so that the device rotates with the rotor during operation of the electric machine. Cooling medium is fed into the annular body, which as a result of the rotation of the device is thrown through the at least one through opening and/or the at least one notch in the outer wall of the annular body into the end winding by the centrifugal forces caused thereby.

This advantageously achieves the supply and radial distribution of cooling medium in the winding overhang, preventing the cooling medium from entering the air gap between the stator and rotor, since the cooling medium is thrown directly into the winding overhang due to the centrifugal forces acting. From there, the cooling medium runs down by gravity in and outside of the end winding and reaches a receiving device, for example a transmission oil sump.

The ring body is preferably designed in the form of a channel, so that an open receiving space for receiving the cooling medium is formed in the interior of the ring body. Based on the state of the device attached to the rotor, the cooling medium is preferably supplied through a cooling medium line, which preferably supplies the cooling medium from a side of the device facing away from the rotor into the open receiving space. The cooling medium line is preferably arranged in a fixed position relative to the rotor and does not rotate. In particular, the cooling medium line is arranged on a housing of the electrical machine.

Preferably, a number of through-openings and/or notches are arranged on the outer wall, the through-openings being evenly spaced along the circumference of the outer wall. By providing a plurality of through openings or notches, cooling medium can be discharged uniformly along the circumference of the device, which advantageously improves the cooling capacity. Alternatively, they can Through-openings may preferably be arranged at irregular intervals along the circumference of the outer wall. In this case, a measure to avoid imbalance is preferably provided.

The amount of cooling medium released can preferably be adjusted by the number, the size and the shape and the distribution along the central longitudinal axis of the channel body of the through-openings or notches. In particular, the quantity and the spatial distribution of the cooling medium can advantageously be adapted to the geometry of the end winding.

Preferably, a number of through-openings are arranged on the outer wall, the through-openings being arranged along at least one concentric annular line circumferentially along the circumference of the outer wall. More than one, in particular two, three, four or five, ring-shaped lines with corresponding through-openings can preferably be provided. The passage openings of the different ring-shaped lines can preferably be arranged at the same or varying distances between the individual lines. The number and/or the distances between the ring-shaped lines can preferably be adapted to the respective geometry of the end winding.

A number of through-openings are preferably arranged on the outer wall, the through-openings being arranged circumferentially along a spiral line on the outer wall of the annular body. This preferred configuration represents a further possibility for adapting the distribution of the cooling medium to the geometry of the end winding. For this purpose, the number of turns and/or the distance between the individual turns of the spiral line can preferably be adapted to the respective design of the end winding.

A surface normal of the opening surface of the at least one through-opening preferably encloses an angle greater than 0° with a radial plane of the annular body. In other words, the at least one through opening is arranged obliquely oriented on the outer wall. As a result, the angle at which the cooling medium is discharged through the through-openings can advantageously be varied. If a number of through-openings is preferably provided, the opening surfaces of the individual through-openings can preferably be arranged at the same angle to the surface normal, or the angles can vary for the individual through-openings and thus preferably be adapted to the geometry of the end winding.

Preferably, the angle of the opening surfaces of the individual through-openings on the outer wall can be varied along an axial position in relation to the central longitudinal axis of the annular body. For example, through-openings in the edge regions of the outer wall can enclose a small angle with the surface normal in relation to the axial position, while in a central region of the outer wall the through-openings enclose a large angle with the surface normal or vice versa. As a result, an area in which the cooling medium is thrown into the end winding can advantageously be adapted and in particular enlarged. Furthermore, preferably in a region of the air gap, the angle of the passage openings arranged here can be adjusted in such a way that the cooling medium does not get into the air gap, but is thrown across the air gap.

If the through-openings are arranged, for example, along a plurality of ring-shaped lines on the outer wall, as explained above, each of the ring-shaped lines can be assigned a specific angle.

The at least one through-opening is preferably arranged in at least one bulge, preferably encircling the outer wall. The at least one bulge is preferably elongate and runs along the ring-shaped or spiral-shaped lines on which the number of through-openings is arranged. In the case of the ring-shaped lines, a plurality of bulges corresponding to the number of ring-shaped lines are preferably provided. The at least one bulge advantageously makes it possible to further optimize the radiation characteristics of the cooling medium and to adapt them to the geometry of the end winding.

The bulge is preferably formed by at least two, in particular at least three or four, wall sections of the outer wall, which are arranged at an angle to one another in a cross-sectional view through a central longitudinal axis of the annular body. Alternatively, the bulge is formed by an outer wall section that is arcuate when viewed in cross section. In this exemplary embodiment, the outer wall is preferably composed of a plurality of conical cylinder sections which form the wall sections. The wall sections are preferably flat.

An edge running in the circumferential direction of the outer wall is preferably formed between two wall sections, with the at least one through-opening being formed in the edge. The edge preferably forms the transition between two wall sections. The edge preferably runs ent speaking of the ring-shaped or spiral-shaped lines along which the at least one or the number of through-openings is arranged. The at least one passage opening can preferably be arranged on a flat area of the wall sections.

In relation to a state of the device arranged on the rotor, the device preferably has an edge facing the rotor and an edge facing away from the rotor, the at least one notch being arranged in the edge facing towards the rotor and/or in the edge facing away from the rotor. The notches preferably serve, on the one hand, to allow cooling medium to drain out of the device and, on the other hand, can also serve to release cooling medium at the end winding during operation of the electrical machine.

In a preferred embodiment, the device has both the at least one through opening and the at least one notch. According to an alternative embodiment, the device has only notches and no through openings. According to yet another alternative embodiment, the device has only the through openings and no notches.

The device preferably comprises metal and/or plastic or consists of metal and/or plastic. The annular body preferably comprises metal and/or plastic or consists of metal and/or plastic.

The object according to the invention is also achieved by an electrical machine having a device with the aforementioned features. The electric machine is preferably arranged in a vehicle, in particular an electric or hybrid vehicle.

The electric machine can preferably only comprise a device which is arranged on one of the winding overhangs. For example, the electric machine can be arranged between an internal combustion engine (ICE) and a gear set of a vehicle, with only one device being arranged on an area of the rotor on the ICE side.

Alternatively, a device can preferably be arranged on each of the winding overhangs of the electrical machine.

• 1 eine Draufsicht auf eine an einem Rotorträger befestigte erfindungsgemäße Vorrichtung,
• 2 eine Schnittdarstellung durch den Stator und Rotor und die Vorrichtung,
• 3 eine ausschnittweise Schnittdarstellung durch den Stator und Rotor und die Vorrichtung,
• 4 eine ausschnittweise Schnittdarstellung der Vorrichtung mit ringförmig angeordneten Durchgangsöffnungen und Zentrierelement gemäß einer ersten Ausführungsform,
• 5 eine ausschnittweise Schnittdarstellung der Vorrichtung mit umfänglich angeordneten Kerben,
• 6 eine ausschnittweise Schnittdarstellung der Vorrichtung mit ringförmig angeordneten Kerben,
• 7 eine ausschnittweise Schnittdarstellung der Vorrichtung mit ringförmig angeordneten Durchgangsöffnungen gemäß einer zweiten Ausführungsform,
• 8 eine ausschnittweise Schnittdarstellung der Vorrichtung mit spiralförmig angeordneten Durchgangsöffnungen auf einer umlaufenden spiralförmigen Vertiefung,
• 9 eine perspektivische Darstellung der Vorrichtung mit spiralförmig angeordneten Durchgangsöffnungen gemäß einer weiteren Ausführungsform,
• 10 a-f ausschnittweise Schnittdarstellungen verschiedener Außenwandgeometrien des Ringkörpers, und
• 11 eine weitere Ausgestaltungsvariante des Ringkörpers mit runder Außenwand.

The invention is explained in more detail below using exemplary embodiments. They show in a purely schematic representation:

• 1 a plan view of a device according to the invention attached to a rotor carrier,
• 2 a sectional view through the stator and rotor and the device,
• 3 a partial sectional view through the stator and rotor and the device,
• 4 a partial sectional view of the device with annularly arranged through-openings and centering element according to a first embodiment,
• 5 a partial sectional view of the device with circumferentially arranged notches,
• 6 a partial sectional view of the device with notches arranged in a ring,
• 7 a partial sectional view of the device with annularly arranged through-openings according to a second embodiment,
• 8th a fragmentary sectional view of the device with through-openings arranged in a spiral shape on a circumferential spiral-shaped depression,
• 9 a perspective view of the device with spirally arranged passage openings according to a further embodiment,
• 10af Partial sectional representations of different outer wall geometries of the ring body, and
• 11 another variant of the ring body with a round outer wall.

1 shows a plan view of the device 100, which is attached to a rotor support 201 of an electrical machine. The device 100 is firmly connected to the rotor 200 or the rotor carrier 201, so that the device 100 is set in rotation when the electric machine is in operation. The device 100 includes a ring body 10 which is arranged concentrically to a winding overhang 301 of the electrical machine.

An open receiving space 23 is formed within the annular body, which receives cooling medium for cooling the end winding 301 . To supply the cooling medium, a cooling medium line 11 is provided, which is arranged on a housing (not shown) of the electrical machine. The cooling medium line 11 protrudes into an opening in the annular body 10 facing away from the rotor 200 into the receiving space 23 in order to cool during the rotation of the rotor 200 and the device 100 to feed medium into the receiving space 23 . On the rotor side, the annular body 13 has an annular bottom surface 24 which delimits the receiving space 23 .

In 2 is a sectional view through the arrangement comprising the stator 300, the end winding 301 of the stator 300, the rotor 200 with rotor carrier 201 and the device 100 is shown. The central longitudinal axis 20 of the annular body 10 is shown, which is identical to the axis of rotation 21 of the rotor 200 . The annular body 10 has a plurality of through openings 13 on its outer wall, only one of which can be seen here. The rotation of the annular body 10 causes cooling medium, which is located in the receiving space 23 , to be thrown outwards into the area of the end winding 301 . This prevents the cooling medium from getting into the air gap between the rotor and stator, since the cooling medium gets directly into the end winding due to centrifugal force. For this purpose, the passage openings 13 are positioned correspondingly close to the end winding 301 . With respect to a radial position, the through-openings 13 are preferably arranged substantially at the level of the air gap.

the inside 2 Ring body 10 shown has an outer wall 14, which is composed of three wall sections 14a, b, c. In addition, the annular body 10 has a bottom surface 24 facing the rotor.

3 shows a section 1 , which shows the geometry of the outer wall of the annular body 10 in detail. The three wall sections 14a, b, c are arranged at an angle to one another, so that the outer wall, viewed as a whole, is curved outwards.

Edges 25 running along the circumference of annular body 10 are formed at the transitions between the individual wall sections 14a, b, c, one of these edges forming an annular line 18, along which annular line 18 the through-openings 13 are arranged. The design of the individual wall sections 14a, b, c, in particular their width and orientation, can influence the radiation characteristics of the cooling medium discharged through the through-openings and can be adapted to the design of the end winding 301. The passage openings 13 include a surface normal 22 in its opening surface, wherein the surface normal 22 can enclose an angle greater than 0° with the radial plane of the annular body 10 . The radial plane is a plane that is arranged perpendicularly to the central longitudinal axis 20 .

In 4 the device 100 according to FIG 2 and 3 shown in part. The device 100 has a bottom surface 24, a centering element 16 being arranged on the bottom surface 24 on an edge 15a facing the rotor, which advantageously facilitates the correct alignment of the device 100 during installation. Furthermore, the annular body 10 has an edge 15b facing away from the rotor.

In 5 the device 100 according to FIG 2 and 3 shown in a further partial representation. A notch 17 is shown here on an edge 15b of the device 100 facing away from the rotor. Preferably, a plurality of notches 17 are equally spaced along the periphery of the rim 15b. This is cut out for two notches 17 in 6 shown.

7 shows a further embodiment of the device 100 with four wall sections 14a, b, c, d, with two central wall sections being arranged in such a way that a local depression is formed in the outer wall 14. In other words, the outer wall has two local bulges, which are designed as two peripheral edges 25 along two ring-shaped lines 18 . A plurality of through-openings 13 are arranged at equal intervals along these lines 18 . The wall section 14d adjoins the bottom surface 24 with the edge 15a facing the rotor, while the wall section 14a adjoins the edge 15b facing away from the rotor.

8th and 9 show a further embodiment of the device 100 having two wall sections 14a, b, which are essentially flat. A plurality of through openings 13 are arranged along a spiral line 19 in the wall section 14a. In 8th the through openings 13 are arranged in a recess running along the spiral line 19, while this recess in the embodiment according to FIG 9 is not provided.

In 10a until 10f various embodiments of the ring body 10 are shown, each with different outer wall geometries. Due to the different configurations of the outer wall, the radiation characteristics can be influenced and adapted to the respective electrical machine.

In the 10a until 10c the outer wall 14 of the annular body 10 has three or four wall sections 14a, b, c, d. The wall sections 14a, b, c, d are arranged at different angles and each enclose an angle with the central longitudinal axis 20 of the annular body 10 . The angles of the individual wall sections 14a, b, c, d are preferably selected in such a way that the outer wall, viewed as a whole, is curved outwards away from a center of the annular body 10 . In 10c an embodiment of the annular body 10 is shown, wherein notches are arranged in the edge 15b facing away from the rotor and the annular body is shorter in relation to its extension along the central longitudinal axis 20 compared to the other embodiments.

In 10a the annular body 14 has a peripheral wall section 14a, a middle wall section 14b, the wall sections 14a and 14b having an opposite orientation in relation to the central longitudinal axis 20, and a bottom wall section 14c, which is oriented analogously to the middle wall section 14b, but a different larger one includes angle with the central longitudinal axis on. Where the peripheral wall section 14a and the central wall section 14b meet, an annular line runs along the circumference of the ring body 10, along which through-openings 13 are arranged on the edge 25.

In the 10b The embodiment shown differs essentially from that in FIG 10a shown in that two central wall sections 14b, c are provided, which are oriented towards each other such that a local depression is formed between them.

In the 10c The outer wall 14 of the annular body 10 shown corresponds essentially to the orientation of the wall sections 14a, b, c, d in FIG 10a shown embodiment, with the difference that the wall sections differ in terms of their length along the central longitudinal axis 20 viewed. The result of this is that the cooling medium is thrown via the notch arranged in the edge 15b facing away from the rotor approximately in the region of the center of the end winding.

10d until 10f show further embodiments of the ring body 10 in relation to the geometry of the outer wall 14. In 10d and 10e the outer wall 14 has two wall sections 14a, b in each case, with a first wall section 14a running essentially parallel to the central longitudinal axis 20. This wall section 14a is connected to a bottom surface 24 of the annular body 10 by a further sloping wall section 14b. through the in 10f The geometry shown with a truncated cone-shaped outer wall is achieved in a particularly advantageous manner in that with lower amounts of cooling oil than is necessary to fill the channel, the cooling medium can only flow to the area of the largest diameter due to the higher centrifugal force there and can mainly be thrown off there. In this way, areas of the end winding along the axis of rotation can be advantageously prioritized in the event of a lack of cooling medium.

In 10d an edge 25 is provided along a helical line 19 with through holes 13 while in 10e are arranged on an imaginary spiral line. The design of the annular body 10 in 10f essentially corresponds to the in 10e shown, with the difference that the wall portion 14a runs obliquely to the central longitudinal axis 20.

11 12 shows an alternative embodiment variant of the outer wall 14 of the ring body, wherein the outer wall 14 can be round or have an outer wall section 14e that is arcuate when viewed in cross-section. According to this configuration, the at least one through opening 13 is arranged along the peripheral surface of the outer wall 14 . The annular body 10 has a bottom surface 24 which merges smoothly, ie without an edge 15a facing the rotor, into the outer wall 14 or the outer wall section 14a of the annular body 10 and together with the outer wall 14 forms a receiving space 23 .

reference list

300

stator

301

winding head

200

rotor

201

rotor carrier

100

contraption

10

ring body

11

cooling medium line

12

retaining ring

13

passage opening

14

outer wall

14a,b,c,d

wall sections

14e

arcuate outer wall section

15a

edge facing the rotor

15b

edge facing away from the rotor

16

centering element

17

score

18

annular line

19

spiral line

20

central longitudinal axis

21

axis of rotation

22

surface normal

23

recording room

24

floor space

25

edge

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited 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 102017201390 A1 [0003]
• DE 102017214560 A1 [0004]
• DE 2017202752 A1 [0005]
• DE 102015223631 A1 [0006]

Claims (11)

Device (100) for supplying a cooling medium during rotation in a winding overhang (301) of a stator (300) of an electrical machine, having an annular body (10), the annular body (10) having a peripheral outer wall (14), and wherein in the peripheral outer wall (14) at least one through-opening (13) and/or a notch (17) is arranged. Device (100) according to claim 1 wherein a number of through-openings (13) and/or notches (14) are arranged on the outer wall (14), and wherein the through-openings (13) are arranged along the periphery of the outer wall (14) evenly spaced. Device (100) according to claim 1 or 2 wherein a number of through openings (13) are arranged on the outer wall (14), the through openings (13) being arranged along at least one concentric annular line (18) circumferentially along the periphery of the outer wall (14). Device (100) according to claim 1 wherein a number of through-openings (13) are arranged on the outer wall (14), and wherein the through-openings (13) are arranged circumferentially along a spiral line (19) on the outer wall (14) of the annular body (10). Device (100) according to one of the preceding claims, wherein a surface normal (22) of the opening surface of the at least one through-opening (13) encloses an angle greater than 0° with a radial plane of the annular body (10). Device (100) according to one of the preceding claims, wherein the at least one passage opening (13) is arranged in at least one bulge, preferably encircling the outer wall (14). Device (100) according to claim 6 , wherein the bulge is formed by at least two, in particular at least three or four, wall sections (14a, 14b, 14c, 14d) of the outer wall (14), which in a cross-sectional view through a central longitudinal axis (20) of the annular body (10) at an angle are arranged relative to each other or wherein the bulge is formed by an outer wall section (14e) which is arc-shaped in a cross-sectional view. Device (100) according to claim 7 , wherein an edge (25) running in the circumferential direction of the outer wall (14) is formed between two wall sections (14a, 14b, 14c, 14d), and wherein the at least one through-opening (13) is formed in the edge (25). Device (100) according to one of the preceding claims, wherein the device (100) has an edge (15a) facing the rotor and an edge (15b) facing away from the rotor in relation to a state of the device (100) arranged on the rotor (200), the at least one Notch (17) is arranged in the rotor-facing edge (15a) and/or in the edge (15b) facing away from the rotor. Device (100) according to one of the preceding claims, wherein the device (100) comprises metal and/or plastic or consists of metal and/or plastic. Electrical machine, having a device (100) according to one of the preceding claims

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