DE102019124209B4 - Cooling system for an electric motor - Google Patents

Abstract

Cooling system (10) for an electric motor comprising a stator with winding heads and a rotor (11) with a rotor shaft (12), the rotor (11) having at least one end plate (13), the at least one end plate (13) having a first section (20a), the at least one end plate (13) in the first section (20a) being conically shaped around the rotor shaft (12), the rotor (11) comprising a laminated core (14) and the at least one end plate (13) has at least one outlet opening (17) which is set up to discharge a coolant from the laminated core (14) of the rotor (11), the at least one outlet opening (17) being set up to fanned out and atomize the outflowing coolant in a targeted manner, the at least an end plate (13) is designed in such a way that an ejection of a jet of the coolant leads to an axial fanning out of the jet and a radial inside of the end windings of the stator is evenly wetted and cooled rd, characterized in that the at least one end plate (13) has a border (21), the border (21) delimiting the first section (20a) of the at least one end plate (13) radially outward starting from the rotor shaft (12) , wherein the border (21) forms at least one highlight (18) which is formed symmetrically around the at least one outlet opening (17), the highlight (18) being triangular, the triangle being arranged in relation to the outlet opening (17), that an exiting oil volume flow hits a center point of the triangle centrally.

Description

The present invention relates to a cooling system for an electric motor comprising a stator with end windings and a rotor with a rotor shaft.

In the prior art, cooling systems for electrical machines with direct oil cooling in the active space are known.

From the DE 10 2016 208 770 A1 an electrical machine is known which has a rotor with a hollow shaft and a stator with end windings that are acted upon by a coolant that is passed via the rotor to attachment elements in the end area of the rotor and distributed evenly to the winding heads of the stator due to the geometry of the attachment elements will.

From the DE 10 2015 223 631 A1 a rotor hollow shaft with a cooling medium distribution element is known. The hollow rotor shaft is equipped with laminated cores and has the cooling medium distribution element, which is arranged inside a rotor and uniformly emits a coolant via outlet openings on stator coils.

From the DE 10 2013 020 332 A1 an electrical machine, in particular an asynchronous machine, is known. The electrical machine has a stator with end windings and an oil-cooled rotor with laminated cores, with oil flowing to the end windings of the stator via outlet openings of a rotor shaft for uniform cooling.

From the generic document US 2014/0 077 632 A1 a rotor of an electrical machine with internal permanent magnets (IPM) is known comprising a core with first and second axial ends, longitudinal channels extending between the ends and a plurality of permanent magnets arranged in the channels, and a first conical Spring washer with a peripheral edge attached to the first axial end and a second conical spring washer with a peripheral edge attached to the second axial end.

From the document CN 104 821 671 A a compact rotor structure with rotor wind path is known, which comprises a rotating shaft, a rotor core, a sliver, an end ring, a rotor press plate at the outlet air end and an air inlet rotor press plate, wherein the rotor core is encased in a rotating shaft, the fiber ribbon is inserted into the rotor core and the End ring is attached to the end of the thread.

From the document JP 2009 - 273 285 A An end plate is known which adheres firmly to the end in the direction of the rotating shaft of the stator core and has several spaces for storing coolants that have flowed in from coolant inflow openings which are arranged next to one another in the circumferential direction of the end plate, as well as coolant nozzles for ejecting stored coolant to the coil end. The coolant nozzles are each arranged in plurality in the circumferential direction of the end plate.

From the document DE 10 2017 108 736 A1 An electric machine for a vehicle is known which comprises a stator which has end windings extending axially from the stator and a rotor which is arranged in the stator and comprises an end cap having an outer surface in which outlets and a grooved outer periphery an edge are formed, wherein the edge is designed to distribute coolant discharged from the outlets during the rotation to the outer surface at different axial locations of the end windings.

The object of the present invention is to provide a device and a system which improve the cooling performance of an electric motor.

This object is achieved by a cooling system with the features of claim 1 and by an end plate with the features of claim 6. Advantageous developments and designs are the subject of the description and description of the figures.

The invention relates to a cooling system for an electric motor comprising a stator with end turns and a rotor with a rotor shaft, the rotor having at least one end disk, the at least one end disk having a first section, the at least one end disk being conical in the first section the rotor shaft is formed, the rotor comprising a laminated core and the at least one end plate having at least one outlet opening which is set up to discharge a coolant from the laminated core of the rotor, the at least one outlet opening being set up to specifically fan out and atomize the outflowing coolant , wherein the at least one end disk is designed such that an ejection of a jet of the coolant leads to an axial fanning out of the jet and a radial inside of the end windings of the stator is evenly wetted and cooled.

According to the invention, the at least one end plate has a border, the border delimiting the first section of the at least one end plate radially outward starting from the rotor shaft, the border forming at least one prominence which is formed symmetrically around the at least one outlet opening, the highlighting being triangular, the triangle usually being arranged in relation to the outlet opening in such a way that an exiting oil volume flow impinges centrally on a center point of the triangle.

At least one end plate is usually made of a metal. Alternatively, at least one end plate is made from a plastic.

Conical here means that the first section has a cone base and a cone tip, the cone tip pointing away from the rotor and the cone base pointing towards the rotor.

A coolant is usually an oil that flows through the rotor as an oil volume flow. Alternatively, the coolant is a cooling fluid or a cooling liquid.

The at least one outlet opening is connected to at least one channel of the laminated core of the rotor so that an oil volume flow, which is introduced into the electric motor via the rotor shaft, can flow into the laminated core via channels and can exit the rotor via the laminated core via the outlet openings of the end plate .

In one embodiment, the at least one end plate comprises at least six outlet openings, the outlet openings being formed radially around the rotor shaft in the end plate at uniform intervals.

The cooling system according to the invention offers the advantage that a targeted discharge of a rotor oil volume flow onto an inside of the end windings of the stator of the cooling system is set up. The present invention thus combines an application of internal rotor cooling with oil with a targeted discharge of a rotor oil volume flow onto the inside of the stator end windings in order to develop an additional cooling effect there and to make the cooling effect more even there. The direct coolant volume flow or oil volume flow results in better cooling of the end winding. In addition, the fanning out of the oil volume flow means that there is less risk of erosion on the end winding of the stator.

In a further development, the at least one outlet opening is formed in the first section of the at least one end plate. The at least one outlet opening is generally formed on the cone base of the at least one conically configured end disk and thus on the edge of the first section. The outlet opening is generally oval in shape. In an alternative embodiment, the outlet opening is circular or angular.

The outlet opening of the at least one end plate is designed in such a way that shedding the oil volume flow leads to an axial fanning out of the oil volume flow and the radial inside of the end windings of the stator is evenly wetted and thereby cooled. The cooling system according to the invention with the at least one end disk thus supplies an oil volume flow specifically to the end windings and fanned it out before reaching the end windings in order to reduce a speed of the outflowing oil volume flow that hits the end windings.

In one embodiment, the at least one end plate comprises six outlet openings, the outlet openings being arranged mirror-symmetrically to one another in sections that remain the same.

In a further embodiment, the border is usually designed as a second section of the end plate, the border being formed on the cone base of the conical end plate. The border is generally circular around the first section of the end disk. The border of the at least one end disk is usually set up and designed in such a way that a jet of the coolant of an oil volume flow is ejected to an axial fanning out of the oil volume flow and a radial inside of the end windings of the stator is evenly wetted and cooled.

In one embodiment, the border is formed at least in some areas. As a rule, the border is formed around at least one outlet opening. This offers the advantage that, at the position of the oil volume flow outlet, the oil volume flow can be fanned out through the border. Such a special geometry of the end plate can ensure that the oil volume flow is shed in such a way that the oil volume flow is fanned out axially. By fanning out the oil volume flow, there is also less local concentration of an impact of the oil volume flow on the end windings of the stator, which reduces the risk of erosion on the end winding.

According to the invention, the highlighting is triangular, the triangle usually being arranged in relation to the outlet opening in such a way that an emerging oil volume flow hits the center of the triangle centrally. The tip of the triangle is set up to guide, fan out and atomize the impinging oil volume flow. As a rule, at least one end plate has each a highlight, which is formed symmetrically around an outlet opening.

In one embodiment, the end plate has six outlet openings, a triangular protrusion being arranged axially around each outlet opening. I. E. the highlights are usually formed in a constant radius around the first section of the end plate. The highlights only occur in the case of outlet openings.

In a further development, an end plate is arranged at each end of the laminated core. The arrangement of one end plate at each end of the laminated core of the rotor offers the advantage that the cooling capacity of one end plate can be increased by using a second end plate.

In one embodiment, the laminated core has at least one channel which is set up to guide a coolant in the direction of at least one outlet opening of a respective end disk. The laminated core is usually fed with an oil volume flow through channels on the rotor shaft. The laminated core in turn comprises at least one channel which is set up to guide the oil volume flow through the laminated core to at least one of the end plates. The at least one channel of the laminated core is generally connected to at least one outlet opening of the respective end disk. The oil or the oil volume flow is thus supplied via the individual channels of the laminated core. The geometry of the channels limits the supply of the coolant tangentially. As a rule, there is no additional restriction on the supply beyond the channel geometry.

As a rule, the laminated core comprises at least two channels, a first channel being set up to guide an oil volume flow to a first end disk and a second channel being set up to guide an oil volume flow to a second end disk.

The invention also relates to an end plate for a rotor of an electric motor comprising a stator with winding heads and the rotor with a rotor shaft, the end plate having a first section, the end plate being conical in the first section and the end plate having at least one outlet opening which is set up to discharge a coolant from the rotor, wherein the at least one outlet opening is set up to specifically fan out and atomize the outflowing oil volume flow or the coolant. The end disk is formed on one end of the rotor. The end disk is set up to cover a laminated core of the rotor.

According to the invention, the end plate has at least one border, the border delimiting the first section of the end plate radially outward and forming at least one highlight which is formed symmetrically around the at least one outlet opening, the highlight being triangular, the triangle such as to The outlet opening is arranged so that an exiting oil volume flow hits the highlight centrally or in the region of the triangle tip.

Conical here means that the first section has a cone base and a cone tip, the cone tip pointing away from the rotor and the cone base pointing towards the rotor. The first section is designed to taper conically in the direction of the cone tip up to the rotor shaft.

The end disk is usually made of a metal. Alternatively, the end plate is made from a plastic. The at least one outlet opening is connected to at least one channel of the laminated core of the rotor. An oil volume flow, which is introduced into the electric motor via the rotor shaft, can thus flow into the laminated core via channels and exit the end plate via the laminated core via the outlet openings. In one embodiment, the end plate comprises at least six outlet openings, the outlet openings being formed radially around the rotor shaft in the end plate at uniform intervals.

The end disk according to the invention offers the advantage that a targeted discharge of a rotor oil volume flow onto an inside of the end windings of the stator of the cooling system can be achieved. The end plate thus enables the combination of internal rotor cooling with oil with a targeted discharge of a rotor oil volume flow onto the inside of the stator end windings in order to develop an additional cooling effect there and to make the cooling effect more even there. The direct oil volume flow from the laminated core results in better cooling of the winding head. In addition, the fanning out of the oil volume flow means that there is less risk of erosion on the end winding of the stator.

The border is usually aligned as a second section of the end plate and is usually formed at least in some areas on the cone base of the conical end plate. The border is generally circular around the first section of the end disk. In an alternative embodiment, the end sheath is oval or serrated or has a different one geometric shape. The edge of the end disk is usually set up and designed in such a way that shedding an oil volume flow leads to an axial fanning out of the oil volume flow and the inside of the radial end windings of the stator is evenly wetted and cooled.

Such a special geometry of the end plate can ensure that the oil volume flow is shed in such a way that the oil volume flow is fanned out axially. The fanning out results in a lower local concentration of an impact or impact of the oil volume flow and thus the risk of erosion on the end windings of the stator is reduced.

The border is usually designed as a triangular highlight, the triangle being arranged in relation to the outlet opening in such a way that an exiting oil volume flow hits the highlight centrally or in the area of the triangle tip. The tip of the triangle is set up to guide, fan out and atomize the impinging oil volume flow. In one embodiment, the end plate has six outlet openings, a triangular protrusion being arranged axially around each outlet opening. I. E. the highlights are usually formed in a constant radius around the first section of the end plate. The highlights only occur in the case of outlet openings.

• 1 eine Seitenansicht einer Teilansicht einer Ausführungsform eines erfindungsgemäßen Kühlsystems für einen Elektromotor,
• 2 eine perspektivische Seitenansicht auf einen - in 1 gezeigten - Rotor mit einer Ausführungsform einer erfindungsgemäßen Endscheibe,
• 3 eine Simulation eines berechneten Abwurfverhaltens eines Ölvolumenstroms des - in den 1 und 2 gezeigten - Kühlsystems.

The invention is shown schematically on the basis of embodiments in the drawing and is described further with reference to the drawing, the same components being identified by the same reference numerals. It shows:

• 1 a side view of a partial view of an embodiment of a cooling system according to the invention for an electric motor,
• 2 a perspective side view of one - in 1 shown - rotor with an embodiment of an end disk according to the invention,
• 3 a simulation of a calculated ejection behavior of an oil volume flow of the - in the 1 and 2 shown - cooling system.

1 shows a side view of a partial view of an embodiment of a cooling system according to the invention 10 for an electric motor with a rotor 11th and a rotor shaft 12th .

Part of the rotor is shown 11th with the rotor shaft designed as a hollow shaft 12th . The rotor 11th has a laminated core 14th on, with the rotor shaft 12th with the laminated core 14th of the rotor via channels 22nd connected is.

The channels 22nd are set up an oil flow rate from the rotor shaft 12th to the laminated core 14th respectively. The oil volume flow is along the oil guide shown 19th from the rotor shaft 12th through the laminated core 14th guided.

In the present embodiment it is shown that the cooling system 10 two end plates 13th includes, each at one end 15a , 15b of the laminated core 14th of the rotor 11th are arranged. To simplify the description, an end plate is used here 13th at one end 15a of the laminated core 14th described. What has been said also applies to the end plate 13th at the second end 15b of the laminated core 14th .

The end disk 13th has a first section 20a on, in which this is conical. It is shown that the end disk 13th a cone point in this area 24 and a cone base 23 having, the cone base 23 to the rotor 11th is designed pointing and the cone tip 24 from the rotor 11th is pioneering.

The conical end cap 13th has an outlet opening 17th on, from which an oil volume flow, which from the laminated core 14th of the rotor 11th flows out, can be diverted. The outlet opening 17th is at the base of the cone 23 the end disk 13th educated.

The end disk 13th furthermore has at least one outlet opening 17th on, with the outlet opening 17th in the present embodiment on the cone base 23 of the first section 20a the end disk 13th is trained. In the present side view there is only one outlet opening 17th shown. As a rule, the end plate 13th at least two, in particular six, outlet openings 17th , on.

It is also shown that the end disk 13th a border 21 includes. The border 21 is radially symmetrical about the first section 20a the end disk 13th educated. In the present embodiment, the border is 21 as at least regionally trained emphasis 18th educated. The emphasis 18th is triangular, the tip of the triangle being rounded. The emphasis 18th is axially around the outlet opening 17th educated. The emphasis is on 18th designed such that one from the outlet opening 17th outflowing oil volume flow centrally on the triangular highlighting 18th meets and by the rounded tip of the triangular highlight 18th is fanned out or atomized axially.

The at least one outlet opening 17th is with at least one channel 22nd of the laminated core 14th of the rotor 11th connected, so that an oil volume flow of the oil guide 19th , which over the rotor shaft 12th is introduced into the electric motor via channels 22nd in the laminated core 14th flows and over the laminated core 14th via the outlet openings 17th the end disk 13th from the rotor 11th exit.

2 shows a perspective side view of one - in 1 shown - rotor 11th with an embodiment of an end disk according to the invention 13th . A first ending is shown 15a of the rotor 11th , with a second end 15b which is the first ending 15a is formed opposite, is indicated.

It shows 2 the rotor shaft 12th , which in the present case is designed as a hollow shaft, as well as the end plate 13th that is in the first section 20a Is conical, wherein at the cone base 23 six outlets 17th are trained. The outlets 17th are axially symmetrical.

To the first section 20a the border is adjacent 21 formed, the border 21 in the present embodiment as at least regionally designed highlights 18th is trained. The highlights 18th are triangular in shape, with the protrusions axially around the outlet opening 17th are trained. The triangular shaped highlights 18th are rounded in the present embodiment and dimensioned such that one from an outlet opening 17th outflowing oil volume flow hits a surface of the triangle centrally or in the area of the triangle tip and is thereby fanned out or atomized axially.

3 shows a simulation of a calculated ejection behavior of an oil volume flow of the - in the 1 and 2 shown - cooling system 10 . The fanning out of the oil volume flow is shown on a highlight 18th and the atomization impinging on an end turn of the stator.

List of reference symbols

10

Cooling system

11th

rotor

12th

Rotor shaft / hollow shaft

13th

End disk

14th

Laminated core

15a, 15b

Ends of the rotor

16

channel

17th

Outlet openings

18th

Emphasis

19th

Oil guide

20a

first section

21

Border

22nd

channels

23

Cone base

24

Cone point

Claims (6)

Cooling system (10) for an electric motor comprising a stator with winding heads and a rotor (11) with a rotor shaft (12), the rotor (11) having at least one end plate (13), the at least one end plate (13) having a first section (20a), the at least one end plate (13) in the first section (20a) being conically shaped around the rotor shaft (12), the rotor (11) comprising a laminated core (14) and the at least one end plate (13) has at least one outlet opening (17) which is set up to discharge a coolant from the laminated core (14) of the rotor (11), the at least one outlet opening (17) being set up to fanned out and atomize the outflowing coolant in a targeted manner, the at least an end plate (13) is designed in such a way that an ejection of a jet of the coolant leads to an axial fanning of the jet and a radial inside of the end windings of the stator is evenly wetted and cooled rd, characterized in that the at least one end plate (13) has a border (21), the border (21) delimiting the first section (20a) of the at least one end plate (13) radially outward starting from the rotor shaft (12) , wherein the border (21) forms at least one highlight (18) which is formed symmetrically around the at least one outlet opening (17), the highlight (18) being triangular, the triangle being arranged in relation to the outlet opening (17), that an exiting oil volume flow hits a center point of the triangle centrally. Cooling system (10) Claim 1 , characterized in that the at least one outlet opening (17) is formed in the first section (20a) of the at least one end plate (13). Cooling system (10) according to one of the preceding claims, characterized in that the border (21) is formed at least in certain areas. Cooling system (10) according to one of the preceding claims, characterized in that an end plate (13) is arranged at each end (15a, 15b) of the laminated core (14). Cooling system (10) according to one of the preceding claims, characterized in that the Laminated core (14) has at least one channel (16) which is set up to guide a coolant in the direction of at least one outlet opening (17) of a respective end plate (13a, 13b). End plate (13) for a rotor (11) of an electric motor comprising a stator with winding heads and the rotor (11) with a rotor shaft (12), the end plate (13) having a first section (20a), the end plate (13) is conical in the first section (20a) and wherein the end plate (13) has at least one outlet opening (17) which is set up to discharge an oil volume flow from the rotor (11), wherein the at least one outlet opening (17) is set up, fanning out and atomizing the outflowing oil volume flow, characterized in that the end plate (13) has at least one border (21), the border (21) delimiting the first section (20a) of the end plate (13) radially outwards and at least one Elevation (18) formed symmetrically around the at least one outlet opening (17), the elevation being triangular, the triangle in such a way as to the outlet opening (17) it is arranged that an exiting oil volume flow hits the highlight (18) centrally or in the area of the triangle tip.

Images