DE102022208566A1 - Rotor of an asynchronous machine - Google Patents

Abstract

A rotor (10) of an asynchronous machine is proposed, comprising at least one short-circuit ring (11), cage bars (20) and a laminated core (22). The at least one short-circuit ring (11) is annular, with a first axial end region (12) of the at least one short-circuit ring (11) having at least a first section (16) with a first inner diameter (40) and at least a second section (17) with a , compared to the first inner diameter (40), has a larger, second inner diameter (41) in order to coolant (60) emerging from a shaft (50) into cooling channels (23) between the cage bars (20) and the laminated core (22) or in the laminated core (22) in or out of the cooling channels (23).

Description

The invention relates to a rotor of an asynchronous machine according to claim 1.

A problem with every electrical machine is the heat development in the rotor due to power loss. The resulting temperatures force a reduction in performance during continuous operation, otherwise the expected service life will not be achieved. It is known from the prior art to counteract losses by reducing the continuous power. Furthermore, the use of cost-intensive copper instead of aluminum in the rotor is known in order to reduce losses.

The DE 10 2011 117 517 A1 discloses, for example, to provide a device for the flow of coolant through the rotor, which includes coolant lines in both press plates that run from the rotor shaft in the direction of the conductor bars. This is intended to keep the engine robust and evenly cooled.

The US 10,998,785 B2 on the other hand, discloses that end rings of the rotor, which connect the rotor rods to one another at the axial end, have corresponding slots for receiving the rods, the radial height of the slots being greater than the radial height of the rotor rods, so that the lower sections of the slots are free, in order to be able to represent cooling structures.

The DE 10 2014 018 223 A1 describes an electrical machine, wherein a cooling channel extends from a first axial end to an opposite axial end of the rotor laminated core and can be supplied with a coolant via a coolant inlet channel, the coolant inlet channel in the short-circuit ring extending radially from an inner radius of the short-circuit ring to the cooling channel extends.

The object of the present invention is to further develop a rotor of an electrical machine in such a way that effective cooling takes place by means of an optimal distribution of the coolant.

The aforementioned task is solved by a rotor of an asynchronous machine, which includes at least one short-circuit ring, cage bars and a laminated core. The rotor preferably has two short-circuit rings. The cage bars extend from one axial end to a second axial end through the laminated core and are received in corresponding recesses in preferably two short-circuit rings.

The at least one short-circuit ring is annular, with a first axial end region having at least a first section with a first inner diameter and at least a second section with a second inner diameter, the second inner diameter being larger in comparison to the first inner diameter. The different sections serve to guide coolant, which emerges from a shaft of the asynchronous machine of the rotor, into cooling channels or out of the cooling channels. The cooling channels can be formed between the cage bars and the laminated core or in the laminated core, for example as through openings that extend over the entire length of the laminated core.

The annular short-circuit ring has, in particular, the first inner diameter throughout the entire first section and the second inner diameter along the entire second section.

The second inside diameter preferably corresponds to at least 105%, further preferably at least 110%, most preferably at least 120%, of the first inside diameter.

The shaft preferably has an axial bore for guiding coolant. In particular, coolant emerges from radial shaft bores within the shaft. The shaft bores are preferably arranged in such a way that they open shortly before an axial end of the laminated core.

Both short-circuit rings are preferably annular, with the second short-circuit ring also having at least a first section with a first inner diameter and at least a second section with a second inner diameter, the first inner diameter being larger in comparison to the first diameter.

The first section and the second section of the at least one short-circuit ring are preferably arranged adjacent to one another in the circumferential direction. In particular, each first section and/or each second section of the first axial end region of the at least one short-circuit ring covers a plurality of cage bars in the circumferential direction. Thus, each first and/or each second section can preferably cover at least three, preferably at least four cage bars, and further preferably at most 8, most preferably at most 6, cage bars. In particular, each first section and/or each second section comprises at least an angular range of 5°, preferably at least 10°. Furthermore, everyone can be first Section and/or every second section span a maximum of 25%, preferably a maximum of 15%.

Preferably, at least one cooling channel is formed with respect to each cage bar. The cooling channel of a cage bar can be formed at a radially inner end of the cage bar. At the radially inner end of the cage rod, coolant can thus flow along the cage rod from one axial end to the other axial end, so that the cage rods are effectively cooled. Furthermore, at least one cooling channel of a cage rod can be formed laterally. The cooling channel can therefore not be formed at the radially inner end, but is formed laterally in the circumferential direction. Furthermore, a cooling channel can be formed on both sides of the cage bar. The at least one lateral cooling channel can extend over the entire radial extent of the cage rod.

The cooling channels between the cage bars and the laminated core can be formed by targeted shaping on the laminated core and/or on the cage bars. Furthermore, these can be formed into a laminated core through the use of cage bars with increased joining play.

The at least one short-circuit ring preferably has a plurality of first sections and a plurality of second sections, the first sections and the second sections alternating in the circumferential direction. Each first section is therefore adjacent to a second section on both sides in the circumferential direction. The same applies to every second section.

Above all, a second axial end region adjoins the first axial end region. Preferably, the first axial and second axial end regions can each extend over half the thickness of the short-circuit ring. The first axial end region is primarily arranged axially further outward than the second axial end region.

A first section can be assigned to each first section of the first axial end region in the second axial end region. Furthermore, a second section can be assigned to every second section of the first axial end region in the second axial end region. The first section of the second axial end region in particular spans the same angular range in the circumferential direction as the first section of the first axial end region. This preferably applies analogously to the second sections.

The first section of the second axial end region can have a third inside diameter at least in the middle, the third inside diameter being larger than the first inside diameter, so that a collecting area for coolant emerging from the shaft is created. The collection area can also be understood as a deflection area.

By providing different inner diameters, cooling channels arranged, for example, at the radially inner end of the cage bars can be covered by the at least one first section in the axial direction. Coolant preferably exits in the longitudinal direction, which corresponds to the axial direction, at the level of the second axial end region. While the first section of the first axial end region covers cooling channels in the axial direction, the larger third inner diameter ensures that a collecting area for coolant is created. Coolant escaping from the shaft is thus moved by centrifugal forces towards the inner wall of the short-circuit ring and can collect in the collecting area. The first section of the first axial end region thus projects radially inwards and thus serves as a wall section in the axially outer direction. The first inner diameter can also be provided at the end regions of the first section of the second axial end region in order to form wall sections in the radial direction for the collecting region. The coolant can flow from the collecting area into a cooling channel, preferably in a radially inner arrangement with respect to the cage bars, and thus move to the other axial end area.

Preferably, with respect to each cage bar, a first section of the first axial end region is arranged on one short-circuit ring and a second section of the first axial end region is arranged on the other short-circuit ring. While the coolant is effectively introduced into cooling channels at a short-circuit ring, preferably through a collecting region, the coolant can exit the cooling channel at the second axial end region, where a second section is then arranged. In particular, the coolant exits through openings that can be open or closed towards the inner diameter of the short-circuit ring.

Preferably, the second section of the second axial end region also has the second inner diameter. In other words, the second inner diameter extends over the entire thickness of the short-circuit ring in the axial direction. The coolant can thus exit in a second section in the axial direction. It can flow over the end face of the short-circuit ring and then form a cooling flow in the direction of the winding head.

In addition, at least one further guide element can be provided, which is preferably fitted onto the shaft. This guide element can ensure the guidance of the cooling medium from the radial shaft bores to the short-circuit ring.

The at least one first section may have a first outside diameter and the at least one second section may have a second outside diameter, wherein the first outside diameter is larger than the second outside diameter. The first outside diameter preferably corresponds to at least 105%, further preferably at least 110%, most preferably at least 120%, of the second outside diameter.

The different sections can therefore not only have different inside diameters, but also different outside diameters. The first outer diameter and the second outer diameter preferably extend over the entire thickness of the short-circuit ring. Furthermore, the outside diameter can be the same in both sections.

A different outer diameter serves in particular to allow coolant to escape from cooling channels with respect to the cage bars if these are not arranged at the radially inner end, but, for example, to the side of the cage bars. In areas with a smaller outside diameter, the coolant outlet can thus be guaranteed, while in areas with a larger outside diameter the coolant is introduced.

When at least one lateral cooling channel is provided, each short-circuit ring is designed in particular with first and second sections in the first axial end region, these extending over the entire thickness of the short-circuit ring. Furthermore, the first sections have a first outer diameter and the second sections have a second outer diameter, each of which also extends over the entire thickness of the short-circuit ring. The second axial end region therefore does not differ in diameter from the first axial end region. The second sections of the second axial end region cover the lateral cooling channels except for a radially inner end section. The coolant can enter the cooling channels in these radially inner end sections. The first sections cover the cooling channels except for a radially outer end section. The coolant can therefore emerge from this radially outer end region.

The first axial end region and/or the second axial end region of the short-circuit rings is preferably formed in one piece. Furthermore, the entire short-circuit ring can be formed in one piece. Despite being divided into first and second sections, the short-circuit rings can therefore be formed in one piece. The cage bars can be molded onto the short-circuit rings. Alternatively, the first axial end region can not be continuous, but rather be formed by segments, which preferably leave exit regions to the winding head free and can only cover the deflection regions into the sheet metal towards the outer diameter.

• 1 eine perspektivische Ansicht eines Rotors;
• 2 einen Längsschnitt des Rotors der 1;
• 3 einen Querschnitt des Rotors der 1 und 2 im Bereich des Blechpaketes;
• 4 den Längsschnitt der 2, wobei ferner der Kühlmittelfluss eingezeichnet ist;
• 5 eine perspektivische Ansicht eines Rotors;
• 6 einen Längsschnitt des Rotors der 5; und
• 7 einen Querschnitt des Rotors der 5 und 6 im Bereich des Blechpaketes.

It shows in a purely schematic representation:

• 1 a perspective view of a rotor;
• 2 a longitudinal section of the rotor 1 ;
• 3 a cross section of the rotor 1 and 2 in the area of the sheet metal package;
• 4 the longitudinal section of the 2 , whereby the coolant flow is also shown;
• 5 a perspective view of a rotor;
• 6 a longitudinal section of the rotor 5 ; and
• 7 a cross section of the rotor 5 and 6 in the area of the sheet metal package.

1 shows a perspective view of a rotor 10. The rotor 10 has two short-circuit rings 11, each of which has a first axial end region 12 and a second axial end region 13 directly adjoining it.

Clearly is in 1 You can see how the short-circuit ring 11 shown on the left has different sections, namely first sections 16 with a first inner diameter 40 and second sections 17 with a larger, second inner diameter 41, while the outer diameter is the same over the entire circumference of the short-circuit ring 11. Furthermore, the shaft 50 is shown with radial shaft bores 51, the shaft bores 51 being arranged in the longitudinal direction, in other words in the axial direction, at the level of the second axial end region 13.

Furthermore, it can be seen how each first section 16 of the first axial end region 12 is assigned a first section 19 of the second axial end region 13, a third inner diameter 42 being formed in this at least in the middle, which is larger than the first inner diameter 40, so that collecting areas 14 for coolant 60, which emerges from the shaft bores 51, are formed. At the end areas of each first section 19, the first inner diameter 40 can also be provided to form wall sections for the collecting area 14.

Furthermore, in 1 the laminated core 22 is shown, through which the cage bars 20, which are in 2 can be seen, extend.

In 2 is a longitudinal section of the rotor 10 1 to see. It can be clearly seen how the first axial end region 12 and the second axial end region 13 of each short-circuit ring 11 directly adjoin one another, with the left in 2 a first section 16 of the first axial end region 12 and a first section 19 of the second axial end region 13 can be seen. These have different inside diameters while the outside diameters are the same. In the left short-circuit ring 11, the first inner diameter 40 is provided in the first axial end region, while the third inner diameter 42 is provided in the second axial end region, so that the collecting region 14 is formed. The radial shaft bores 51 open at the level of the second axial end region 13. In other words, the first section 16 of the first axial end region 12 protrudes radially inwards compared to the second axial end region 13.

Clearly are in 2 You can also see the cage bars 20, which extend from one short-circuit ring to the other short-circuit ring. Two cooling channels 23 can be seen, each of which is arranged at the radially inner end 21 of the corresponding cage rod. At the opposite end, that is to the right 2 , the other short-circuit ring 11 can be seen. The first sections 16 left in 2 A second section 17 is assigned to the right, in which the first axial end region 12 and the second axial end region 13 have a second inner diameter 41, which corresponds to the third inner diameter 42.

In 3 is a cross section through the rotor 10 1 and 2 can be seen in the area of the laminated core 22. The shaft 50, around which the laminated core 22 extends, and the cage bars 20 can be clearly seen. The cooling channels 23, which extend at the radially inner end 21 of the cage bars 20, can be clearly seen. The collecting areas 14, which serve to guide coolant 60 into the cooling channels 23, can also be seen in the first sections 16, while in the second sections 17 the coolant flows directly in the axial direction in the cross section through the larger second inner diameter 41 in the longitudinal direction can.

In 4 is the same longitudinal section 2 can be seen, with the flow of the coolant 60 shown. The coolant 60 flows within the shaft 50 in the axial direction and exits the shaft bores 51 in the radial direction. It is pushed outwards by the centrifugal force and is caught in the collecting area 14. From there it flows through the cooling channel 23 at the radially inner end 21 of the cage rod 20 shown, whereby it then emerges in the axial direction at the other axial end in the second section 17 shown can. The end face of the short-circuit ring is flowed over and the cooling flow can extend in the direction of the winding head.

In 5 a further rotor 10 is shown, in which, as before, first sections 16 and second sections 17 are provided, the first inner diameter 40 and the second inner diameter 41 being constant over the entire first section 16 and second section 17 of the first axial end region 12 as well of the second axial end region 13 extends. The first sections 16 of the first axial end region 12 are therefore assigned first sections 19 of the second axial end region 13 and the second sections 17 of the first axial end region 12 are assigned second sections 15 of the second axial end region 13. However, their inner diameter or outer diameter do not differ. The inner diameter and outer diameter of the areas therefore extend continuously over the entire thickness of the short-circuit ring 11.

While a smaller first outer diameter 43 is provided in the first sections 16, a larger outer diameter 44 is provided in the second sections 17. Again, first sections 16 and second sections 17 alternate in the circumferential direction.

In 5 the shaft 50 with the radial shaft bores 51 as well as the cage bars 20 and the laminated core 22 can be seen again.

In 6 is a longitudinal section, that is, an axial section, of the rotor 10 5 to see. It can be clearly seen how the first inner diameter 40 extends over the entire thickness of the short-circuit ring 11. A second section 17 is arranged with respect to the opposite short-circuit ring 11, with the second inner diameter 41 also extending over the entire thickness of the short-circuit ring.

The outside diameters are also shown. In the aforementioned second section 17 in the right short-circuit ring 11, a second outer diameter 44 is provided, which is larger than the first outer diameter 43, which is provided in the left short-circuit ring 11 in the first section 16. By providing the smaller first outside diameter 43 an opening 18 is made possible in the short-circuit ring 11, whereby the coolant can escape in this way.

7 shows a cross section of the rotor 10 5 and 6 in the area of the laminated core 22. In the present case, the cooling channels 23 extend to the side of the cage bars 20. Each cage bar 20 has two cooling channels 23, one on each side, which extends over the entire radial extent of the cage bar 20. The coolant 60 can enter laterally into the cooling channels 23 on a short-circuit ring 11 in first sections 16 in a radially inner end region of the cage bars 20. At the opposite short-circuit ring 11, in which a second section 17 is then provided, the coolant 60 can emerge again at a radially outer end region.

Clearly is in 7 to see how the second sections 17 and 15 of the short circuit ring 11, at which the viewer looks, cover the side channels 23 except for a radially inner end section. The coolant 60 can enter this radially inner end section.

Furthermore, it can be seen how the first sections 16 and 19 of the short circuit ring 11, which the viewer looks at, cover the side channels 23 except for a radially outer end section. The coolant can emerge from this radially outer end region.

Reference symbol list

10

rotor

12

first axial end region

13

second axial end region

14

Collection area

15

second section of the second axial end region

16

first section of the first axial end region

17

second section of the first axial end region

18

opening

19

first section of the second axial end region

20

cage bar

21

radial inner end

22

Sheet metal package

23

Cooling channel

40

first inner diameter

41

second inner diameter

42

third inner diameter

43

first outside diameter

44

second outside diameter

50

Wave

51

shaft bore

60

coolant

QUOTES INCLUDED IN THE DESCRIPTION

This list of 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.

Cited patent literature

• DE 102011117517 A1 [0003]
• US 10998785 B2 [0004]
• DE 102014018223 A1 [0005]

Claims (10)

Rotor (10) of an asynchronous machine comprising at least one short-circuit ring (11), cage bars (20) and a laminated core (22), the at least one short-circuit ring (11) being annular, characterized in that a first axial end region (12) of the at least a short-circuit ring (11) has at least a first section (16) with a first inner diameter (40) and at least a second section (17) with a second inner diameter (41) which is larger than the first inner diameter (40) in order to consist of a Shaft (50) escaping coolant (60) into cooling channels (23) between the cage bars (20) and the laminated core (22) or in the laminated core (22) or led out of the cooling channels (23). Rotor (10). Claim 1 , characterized in that the rotor (10) has two short-circuit rings (11), both short-circuit rings (11) being annular, a first axial end region (12) of each short-circuit ring (11) having at least a first section (16) with a first inner diameter (40) and at least one second section (17) with a second inner diameter (41) which is larger than the first inner diameter (40) in order to allow coolant (60) emerging from the shaft (50) into the cooling channels (23). between the cage bars (20) and the laminated core (22) or in the laminated core (22) or led out of the cooling channels. Rotor (10). Claim 1 or 2 , characterized in that the first section (16) and the second section (17) are arranged adjacent to one another in the circumferential direction of the short-circuit ring (11). Rotor (10) according to one of the preceding claims, characterized in that at least one cooling channel (23) is formed with respect to each cage bar (20). Rotor (10). Claim 4 , characterized in that a cooling channel (23) of each cage rod (20) is formed at a radially inner end (21) of the cage rod (20). Rotor (10). Claim 4 or 5 , characterized in that at least one cooling channel (23) of a cage rod (20) is formed laterally. Rotor (10) according to one of the preceding claims, characterized in that the at least one first section (16) has a first outside diameter (43) and the at least one second section (17) has a second outside diameter (44), the first outside diameter ( 43) is larger than the second outside diameter (44). Rotor (10) according to one of the preceding claims, characterized in that the at least one short-circuit ring (11) has a plurality of first sections (16) and a plurality of second sections (17), the first sections (16) and the second sections (17 ) alternate in the circumferential direction of the short-circuit ring (11). Rotor (10) according to one of the preceding claims, characterized in that a second axial end region (13) adjoins the first axial end region (12), with each first section (16) of the first axial end region (12) having a first section ( 19) of the second axial end region (13), the first section (19) of the second axial end region (13) having a third internal diameter (42) at least in the middle, the third internal diameter (42) being larger than the first internal diameter ( 40), so that a collecting area (14) is created for coolant (60) emerging from the shaft (50). Rotor (10) according to one of the preceding claims, characterized in that with respect to each cage bar (20) a first section (16) is arranged on one short-circuit ring (11) and a second section (17) on the other short-circuit ring (11).

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