ELECTRIC MOTOR WITH AIR SPLIT AND MAGNETIC SLOT COOLING

Abstract

An electric motor comprises a stator with a radial inner stator core surface and a rotor. The rotor has opposite rotor ends, a radially outer surface located near the radial inner stator core surface to define an air gap, and a radially inner surface spaced from the outer surface to define a plurality of magnetic slots.The rotor comprises a fluid circulation arrangement with at least one fluid channel extending inside the rotor to the outer surface and configured to receive a liquid and a gas, to guide at least one of the liquids and the gas into the plurality of magnetic slots by means of centrifugal force, to guide at least one other of the liquids and the gas into the air gap by means of centrifugal force, and to expel the liquid and the gas from the magnetic slots and the air gap at the rotor ends when the rotor rotates inside the stator in order to cool the electric motor.

Description

INTRODUCTION

[0001] The revelation refers to an electric motor and a vehicle.

[0002] An electric motor converts electrical energy into mechanical energy based on the electromagnetic interaction between permanent magnets and a magnetic field generated by selectively excited coils, thereby producing torque and thermal energy. Cooling the electric motor can reduce the thermal stress on components such as the rotor, stator, motor poles, windings, and / or end windings of the electric motor under or near peak load. Furthermore, cooling can facilitate a more compact motor design. DESCRIPTION

[0003] An electric motor comprises a stator with a radial inner stator core surface and a rotor mounted inside the stator and rotatable about an axis of rotation. The rotor has axially opposite rotor ends, a radial outer rotor surface extending between the axially opposite rotor ends and positioned close to the radial inner stator core surface to define an air gap between them, and a radial inner rotor surface spaced apart from the radial outer rotor surface to define a plurality of magnet slots between them, each configured to receive one or more magnets.The rotor has a fluid circulation arrangement with at least one fluid channel extending within the rotor to the radially outer rotor surface and configured to receive a liquid and a gas, to direct at least one of the liquid and gas into the plurality of magnetic slots by means of centrifugal force, to direct at least another of the liquid and gas into the air gap by means of centrifugal force, and to expel the liquid and gas from the plurality of magnetic slots and the air gap at the axially opposite rotor ends when the rotor rotates in the stator in order to cool the electric motor.

[0004] In one aspect, the electric motor can further comprise a shaft arranged along the axis of rotation. The rotor can have a radially inner rotor core surface that is in contact with the shaft and spaced apart from the radially outer rotor surface. The at least one fluid channel can extend through the rotor from the radially inner rotor core surface to the radially outer rotor surface.

[0005] In an additional aspect, the electric motor can further comprise an impeller that is arranged within the at least one fluid channel and is rotatable about the axis of rotation. The impeller can be configured to separate the liquid and the gas, pumping the gas into the air gap to directly cool the rotor, and injecting the liquid into the majority of the magnet slots to directly cool the majority of the magnets.

[0006] In another aspect, the impeller can have a blade arranged between a first cover and a second cover.

[0007] In another aspect, the rotor can be formed from a plurality of stacked lamellae. The impeller can be embedded between two adjacent lamellae to define an air path from the radially inner rotor core surface to the air gap and a fluid path from the radially inner rotor core surface to the plurality of magnetic slots.

[0008] In one aspect, the rotor can further comprise a pair of end rings, each designed as an impeller and arranged at one of the axially opposite rotor ends. The at least one fluid channel can extend along each of the end rings through the plurality of magnet slots from the radial inner rotor surface to the radial outer rotor surface and through the air gap. The pair of end rings can pump the liquid and gas from the axially opposite rotor ends into the plurality of magnet slots, thereby directly cooling the plurality of magnets.

[0009] In an additional aspect, the rotor can be formed from a plurality of stacked lamellae. These lamellae can include a first central lamella and a second central lamella layered against the first. The first and second central lamellae can be configured together to guide the liquid and gas into the air gap.

[0010] In another aspect, at least one fluid channel can be designed to receive the liquid and gas from the plurality of magnetic slots and to guide the liquid and gas into the air gap by means of centrifugal force in order to expel the liquid and gas from the air gap at the axially opposite rotor ends when the rotor rotates inside the stator, thereby cooling the electric motor.

[0011] In another aspect, the impeller can be designed to pump the gas and liquid into the air gap, thereby directly cooling the rotor.

[0012] In one aspect, the rotor may further comprise a pair of end rings, each defining a gas inlet and located at one of the axially opposite rotor ends.

[0013] In another aspect, the gas can circulate around each of the two end rings, through the gas inlet of each of the two end rings and through the majority of the magnet slots by means of centrifugal force, in order to directly cool the majority of the magnets.

[0014] In another aspect, the impeller can comprise a plurality of blades and a fluid bridge arranged between two adjacent blades of the plurality of blades. The fluid bridge can be configured to direct fluid from the at least one fluid channel to the air gap to directly cool the rotor, and to the plurality of magnet slots to directly cool the plurality of magnets.

[0015] In another aspect, the rotor can further comprise a pair of end rings, each arranged at one of the axially opposite rotor ends. Each of the two end rings can further form a fluid outlet designed to direct the fluid from the plurality of magnetic slots.

[0016] In one aspect, the rotor can be formed from a plurality of stacked lamellae. The plurality of lamellae can include two bridge lamellae, which are adjacent and in contact with the impeller and each designed to minimize the injection of fluid from the at least one fluid channel into the air gap.

[0017] In another aspect, the rotor can also include an end ring designed as an impeller, which is arranged at one of the axially opposite rotor ends.

[0018] In another aspect, the rotor can further comprise a shaft, and the rotor can have a radially inner rotor core surface arranged in contact with the shaft and spaced apart from the radially outer rotor surface. The rotor can also comprise a plurality of vanes stacked side by side to define the at least one fluid channel extending from the shaft to the radially inner rotor surface.

[0019] In one aspect, the end ring can pump the gas to the plurality of magnetic slots and to the air gap, and the plurality of lamellae can direct the liquid to the plurality of magnetic slots without directing the liquid to the air gap.

[0020] In another embodiment, an electric motor comprises a stator with a radial inner stator core surface and a rotor mounted within the stator and rotatable about an axis of rotation. The rotor has axially opposite rotor ends, a radial outer rotor surface extending between the axially opposite rotor ends and positioned close to the radial inner stator core surface to define an air gap between them, and a radial inner rotor surface spaced apart from the radial outer rotor surface to define a plurality of magnet slots between them, each configured to receive one or more magnets. The rotor can be formed from a plurality of stacked laminations.The rotor can have a fluid circulation arrangement with at least one fluid channel extending inside the rotor to the radially outer rotor surface and designed to receive oil and air, to guide the oil into the plurality of magnetic slots by means of centrifugal force, to guide the air into the air gap by means of centrifugal force, and to discharge the oil from the plurality of magnetic slots and the air from the air gap at the axially opposite rotor ends when the rotor rotates inside the stator in order to cool the electric motor.

[0021] A vehicle comprises an electric motor configured to generate torque for propelling the vehicle. The electric motor comprises a stator with a radial inner stator core surface and a rotor mounted within the stator and rotatable about an axis of rotation. The rotor has axially opposite rotor ends, a radial outer rotor surface extending between the axially opposite rotor ends and positioned close to the radial inner stator core surface to define an air gap between them, and a radial inner rotor surface spaced apart from the radial outer rotor surface to define a plurality of magnet slots between them, each configured to receive one or more magnets.The rotor has a fluid circulation arrangement with at least one fluid channel extending within the rotor to the radial outer rotor surface and configured to receive a liquid and a gas, to guide at least one of the liquids and the gas into the plurality of magnetic slots by means of centrifugal force, to guide at least another of the liquid and the gas into the air gap by means of centrifugal force, and to expel the liquid and the gas from the plurality of magnetic slots and the air gap at the axially opposite rotor ends when the rotor rotates within the stator in order to cool the electric motor.

[0022] The above features and advantages, as well as other features and associated advantages of this disclosure, will be readily apparent from the following detailed description of illustrative examples and methods for carrying out the present disclosure when considered in conjunction with the accompanying drawings and claims. Furthermore, this disclosure expressly includes combinations and subcombinations of the elements and features described above and below. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 is a schematic representation of a vehicle with an electric motor. Fig. Figure 2 is a schematic representation of a partially cropped perspective view of an embodiment of the electric motor of Fig. 1 including a fluid circulation arrangement. Fig. Figure 3 is a schematic representation of a sectional view of the electric motor of Fig. 2 with an impeller designed to guide fluid and gas within the electric motor. Fig. Figure 4 is a schematic representation of a sectional view of the electric motor and an exploded view of the impeller. Fig. 2. Fig. Figure 5 is a schematic representation of a sectional view of the electric motor. Fig. 2 and Fig. 3, where the impeller defines a gas path. Fig. Figure 6 is a schematic representation of a sectional view of the electric motor. Fig. 2 and Fig. 3, where the impeller defines a fluid path. Fig. 7 is a schematic representation of a sectional view of another embodiment of the electric motor of Fig. 1 with a rotor end ring designed as an impeller and a central lamella grouping. Fig. Figure 8 is a schematic representation of a sectional view of the electric motor and the end ring made of Fig. 7. Fig. Figure 9 is a schematic representation of a top view of an embodiment of the lamella grouping of Fig. 7. Fig. Figure 10 is a schematic representation of a top view of another embodiment of the lamella group of Fig. 7. Fig. Figure 11 is a schematic representation of a section through another embodiment of the electric motor of Fig. 1 with an impeller designed to guide liquid and gas within the electric motor. Fig. Figure 12 is a schematic representation of an exploded view of part of the impeller of Fig. 11. Fig. Figure 13 is a schematic representation of a sectional view of another embodiment of the electric motor of Fig. 1 with an impeller designed to guide liquid and gas within the electric motor. Fig. 14 is a schematic representation of a top view of a part of the impeller of Fig. 13. Fig. Figure 15 is a schematic representation of a sectional view of another embodiment of the electric motor of Fig. 1 with an impeller designed to guide liquid and gas within the electric motor. Fig. Figure 16 is a schematic representation of an exploded view of part of the impeller of Fig. 15. Fig. Figure 17 is a schematic representation of a sectional view of another embodiment of the electric motor of Fig. 1, including a top view of several vanes of the electric motor. DETAILED DESCRIPTION

[0023] Referring to the figures in which the same reference symbols refer to the same elements, an electric motor 10 ( Fig. 1 and Fig. 2) for a vehicle 12 ( Fig. 1) shown. The electric motor 10 and the vehicle 12 can be useful for applications requiring excellent performance due to improved cooling of the electric motor 10. In particular, the electric motor 10 and the vehicle 12 can be useful to reduce both an air gap 14 ( Fig. 3) of the electric motor 10 as well as a plurality of magnetic slots 16 ( Fig. 3) to cool the electric motor 10 in order to improve the operating efficiency of the electric motor 10.

[0024] Referring to Fig. The electric motor 10 is configured to generate the torque T1 for driving the vehicle 12. Therefore, the electric motor 10 and the vehicle 12 can be useful for, but are not limited to, automotive applications, such as electric vehicles, hybrid vehicles, and the like. For example, the vehicle 12, such as a motor vehicle powered by at least one internal combustion engine 28, the electric motor 10, and an energy storage system or device 38, can include the electric motor 10. Alternatively, the electric motor 10 and the vehicle 12 can also be useful for non-automotive applications, such as in aerospace, small and medium-sized enterprises, shipping, mass transit, agriculture, industry, and rail transport.

[0025] In Fig. Figure 1 again shows the vehicle 12 with a powertrain 18. The vehicle 12 can be a commercial vehicle, an industrial vehicle, a passenger vehicle, an aircraft, a watercraft, a train, or the like, but is not limited to these. It is also conceivable that the vehicle 12 is a mobile platform, such as an aircraft, an all-terrain vehicle (ATV), a boat, a personal mobility device, a robot, or the like, to fulfill the purposes of this disclosure. The powertrain 18 can include a first power source, which is represented and configured as an electric motor-generator 10, to generate a first power source torque T1 for driving the vehicle 12 by means of driven wheels 20 relative to a road surface. The electric motor 10 can be configured as a radial flux electric motor, wherein the magnetic flux is perpendicular to an axis of rotation 22 ( Fig. 2) of the electric motor 10 is generated and the air gap 14 between a rotor 24 and stator 26 of the electric motor 10 is arranged concentrically to the axis of rotation 22.

[0026] As in Fig. As shown in Figure 1, the powertrain 18 can also include a second power source 28, such as an internal combustion engine, configured to generate a second power source torque T2. The power sources 10 and 28 can work together to drive the vehicle 12 and can be operationally connected to a transmission assembly 30. The transmission assembly 30 can be configured to transmit the first and / or second power source torques T1, T2 to an axle drive unit 32, which in turn can be connected to the driven wheels 20. The first power source 10, referred to below as the electric motor 10 or motor-generator, can, for example, be attached to the second power source 28, to (or integrated into) the transmission assembly 30, to the axle drive unit 32, or as a separate assembly to the structure of the vehicle 12.As shown, the vehicle 12 can additionally include a programmable electronic control unit 34 configured to communicate via a high-voltage bus 36 and to control the powertrain 18 so that it generates a predetermined torque from the energy source (sum of T1 and T2), as well as various other vehicle systems. The vehicle 12 can also include an energy storage system or energy storage device 38, such as one or more batteries, configured to generate and store electrical energy for supplying power to the power sources 10 and 28.

[0027] Fig. Figure 2 shows a general cross-section of the electric motor 10. The electric motor 10 comprises a rotationally fixed stator 26 with a generally cylindrical stator core 40 and winding slots 42. The stator 26 has a radial inner stator core surface 44. The electric motor 10 also comprises a rotor 24, which is mounted inside the stator 26 and is rotatable about the axis of rotation 22. The stator 26 can contain multiphase AC windings 46 arranged in the winding slots 42, the windings receiving multiphase AC current from an inverter to generate a rotating magnetic field that exerts a torque T1 on the rotor 24. The stator windings 46 can generally be contained in the winding slots 42, with the end turns of the windings 46 extending beyond the boundaries of the cylindrical core 40 at axially opposite stator ends - a first end 48-1 and a second end 48-2.

[0028] Referring again to Fig. 2 The rotor 24 has axially opposite rotor ends – a first end 50-1 and a second end 50-2 – and can comprise a pair of end rings 52, 54, each arranged at one of the axially opposite rotor ends 50-1, 50-2. Furthermore, the rotor 24 can have a ferromagnetic rotor core 56. The rotor core 56 can consist of a relatively soft magnetic material, such as a plurality of lamellae 58 ( Fig. 4), which are stacked against one another and formed from laminated silicon steel. In a permanent magnet machine, the stacked rotor lamellae 58 can contain cavities that form inner pockets for receiving permanent magnets 60, as will be explained in more detail below. In an induction machine, the stacked lamellae 58 can have peripheral slots for receiving current-carrying bars (not shown). Alternative designs of the rotor 24 can also be used and include, for example, surface-mounted permanent magnet and wire-wound rotors 24.

[0029] Referring to the Fig. 2 and Fig. 3. The rotor 24 has a radial outer rotor surface 62 extending between the axially opposite rotor ends 50-1, 50-2 and located near the radial inner stator core surface 44 to define the air gap 14 between them. That is, the air gap 14 can extend between the axially opposite first end 50-1 and the second end 50-2 of the rotor 24. The rotor 24 also includes a radial inner rotor surface 64 spaced from the radial outer rotor surface 62 to define the plurality of magnet slots 16 between them. Each of the plurality of magnet slots 16 is configured to accommodate one of the plurality of magnets 60.

[0030] As in Fig. 2 and Fig. As shown in Figure 3, the rotor 24 also includes a fluid circulation arrangement 66 with at least one fluid channel 68 extending radially within the rotor 24 to the radially outer rotor surface 62. The fluid circulation arrangement 66 is configured to hold a liquid 70 and a gas 72. In particular, the liquid 70 can be a pressurized oil and the gas 72 can be air, and the liquid 70 and the gas 72 can be used to cool the electric motor 10.More precisely, the fluid circulation arrangement 66 is further developed to guide at least one of the liquids and the gas 70, 72 into the plurality of magnetic slots 16 by means of centrifugal force, to guide at least one other of the liquids 70 and the gas 72 into the air gap 14 by means of centrifugal force, and to discharge the liquid 70 and the gas 72 from the plurality of magnetic slots 16 and the air gap 14 at the axially opposite rotor ends 50-1, 50-2 when the rotor 24 rotates within the stator 26 in order to cool the electric motor 10. That is, as explained in more detail below, the fluid circulation arrangement 66 is designed to cool the electric motor 10 by circulating one or more of the liquids 70 and the gas 72 within the air gap 14 and the majority of the magnetic slots 16 of the rotor 24.

[0031] Referring to Fig. 3. The electric motor 10 may further comprise a shaft 74 arranged along the axis of rotation 22, and the rotor 24 may rotate about the shaft 74 within the stationary stator 26. In particular, the rotor 24 may have a radially inner rotor core surface 76 arranged in contact with the shaft 74 and spaced apart from the radially outer rotor surface 62. Furthermore, the shaft 74 may form a passage 78 which is in fluid communication with one or more collecting vessels 80 or inlets for the liquid 70 and / or the gas 72. With reference to Fig. In the embodiment described in section 3, the at least one fluid channel 68 can extend through the rotor 24 from the radially inner rotor core surface 76 to the radially outer rotor surface 62. That is, the at least one fluid channel 68 can extend completely through the rotor core 56.

[0032] As with continued reference to Fig. As described in section 3, the rotor 24 can further comprise an impeller 82, which is arranged in the at least one fluid channel 68 and is rotatable about the axis of rotation 22. The impeller 82 can be designed as a liquid-gas separator impeller to separate the liquid 70 and the gas 72 into one or more streams within the rotor 24 by means of centrifugal force when the impeller 82 rotates about the axis of rotation 22 during operation of the electric motor 10.

[0033] With reference to Fig. 4 In a non-restrictive example, the impeller 82 can comprise a blade 84 arranged between a first cover 86 or guide and a second cover 88 or guide. That is, the impeller 82 can have a three-part structure. As in the Fig. 5 and Fig. As best illustrated in Figure 6, the impeller 82 can be inserted between two adjacent lamellae of the plurality of lamellae 58 to create an air path 90 ( Fig. 5) from the radially inner rotor core surface 76 to the air gap 14 and a fluid path 92 ( Fig. 6) to define from the radially inner rotor core surface 76 to the plurality of magnet slots 16. Thus, the impeller 82, again referring to Fig. 3, are trained to separate the liquid 70 and the gas 72, to pump the gas 72 into the air gap 14 in order to directly cool the rotor 24, and to inject the liquid 70 into the majority of the magnet slots 16 in order to directly cool the majority of the magnets 60.

[0034] More precisely, the liquid 70 and the gas 72, as with continued reference to Fig. As described in section 3, the fluid enters the rotor 24 from the sump 80 or inlet, flows through the passage 78 of the shaft 74 to at least one fluid channel 68, and encounters the impeller 82. The impeller 82 can separate the liquid 70 and the gas 72, so that the gas 72 or the air flows along the air path 90 ( Fig. 4 and Fig. 5) to the air gap 14, around the end rings 52, 54 of the rotor 24 and back to which at least one fluid channel 68 flows. The fluid 70 can flow through the majority of the magnet slots 16 and out of the end rings 52, 54. In this way, the rotor 24 can be cooled by the gas 72 via air gap cooling and the majority of the magnets 60 can be cooled by the fluid 70 via magnet slot cooling.

[0035] Referring to the Fig. 7 and Fig. In another embodiment, the rotor 24 can further comprise the pair of end rings 52, 54, each configured as an impeller 182. In this embodiment, the impeller 82, which refers above to the embodiment of Fig. Reference was made to 3-6, from which at least one fluid channel 68 is removed in place of the end rings 52, 54 designed as impeller 182. That is to say, as in Fig. As best illustrated in Figure 7, the impeller 182 can be integrated into the end rings 52, 54. In particular, the impeller 182 can be cast into the end rings 52, 54 and, as described in Figure 7, Fig. 7 described, comprising a guide 94, an inlet 96 and a vane 84 designed to guide the liquid 70 and the gas 72 to the majority of the magnetic slots 16.

[0036] In particular, as in Fig. Figure 7 shows that at least one fluid channel 68 extends along each of the end rings 52, 54, through the majority of the magnet slots 16, from the radial inner rotor surface 64 to the radial outer rotor surface 62 and through the air gap 14. In this way, the two end rings 52, 54 can pump the liquid 70 and the gas 72 from the axially opposite rotor ends 50-1, 50-2 into the majority of the magnet slots 16, thereby directly cooling the majority of the magnets 60.

[0037] This means that the liquid 70 and the gas 72 can enter the rotor 24 from the sump 80 or the inlet, flow through the passage 78 of the shaft 74 to the at least one fluid channel 68, and encounter the end rings 52, 54, which are designed as impellers 182. Each impeller 182 can separate the liquid 70 and the gas 72, so that the gas 72 flows to the air gap 14, around the end rings 52, 54 of the rotor 24, and back to the at least one fluid channel 68. The liquid 70 can flow from the impeller 182 through the majority of the magnetic slots 16, into and through the air gap 14, and out of the rotor 24 at the axially opposite rotor ends 50-1, 50-2. Thus, the rotor 24 can be cooled by the liquid 70 and the gas 72 using air gap cooling, and the majority of the magnets 60 can be cooled by the liquid 70 and the gas 72 using magnetic slot cooling.

[0038] Furthermore, with reference to Fig. 9 and Fig. 10. In this embodiment, the central portions of the lamellae 58 can have openings 98 to allow the liquid 70 and the gas 72 to enter the air gap 14. More precisely, the plural lamellae 58 can comprise a first central lamella 100 and a second central lamella 102, which is sandwiched against the first central lamella 100. The first central lamella 100 and the second central lamella 102 can be formed together to guide the liquid 70 and the gas 72 into the air gap 14.

[0039] For example, the first central sheet 100 can have the openings 98 which allow the fluid, i.e. the liquid 70 and the gas 72, to flow both through the first central sheet 100 and through the at least one fluid channel 68, e.g. a central channel 104 ( Fig. 8) of the rotor 24, to guide fluid to the air gap 14. That is, the first central lamella 100 can be designed similarly to any other unmodified lamella of the plurality of lamellae 58, but it may lack bridges or parts to define the openings 98 for the fluid flow. Furthermore, the first central lamella 100 may have thickened webs 106 compared to unmodified lamellae of the plurality of lamellae 58 to facilitate adequate fluid flow.

[0040] As in Fig. As shown in Figure 9, the second central lamella 102 can generally be star-shaped and also have openings 98 to guide the liquid 70 and the gas 72 into the air gap 14. Therefore, when combined with and stacked against the first central lamella 100, the second central lamella 102 can interact with the first central lamella 100 to act as a secondary central impeller 282 and further facilitate the flow of liquid into the air gap 14.

[0041] With reference to Fig. In another example, a central lamella 102 can be modified compared to a standard, unmodified lamella of the plurality of lamellae 58, defining the openings 98 to allow fluid flow. Furthermore, the central lamella 102 can be inserted between two of the plurality of lamellae 58 to form the central channel 104 and direct fluid into the air gap 14. That is, although not shown, the lamella 58 – central lamella 100 – lamella 58 can form a three-part structure to create a fluid passage and direct fluid into the air gap 14. Furthermore, the central lamella 102 can have thickened webs 106 compared to unmodified lamellae of the plurality of lamellae 58 to facilitate adequate fluid flow.

[0042] Therefore, referring again to Fig. 7, in this embodiment the at least one fluid channel 68 is designed such that it receives the liquid 70 and the gas 72 from the plurality of magnetic slots 16 and directs the liquid 70 and the gas 72 by means of centrifugal force into the air gap 14 in order to discharge the liquid 70 and the gas 72 from the air gap 14 at the axially opposite rotor ends 50-1, 50-2 of the rotor 24 when the rotor 24 rotates inside the stator 26 in order to cool the electric motor 10.

[0043] Referring to Fig. In another embodiment, the rotor 24 can further comprise the pair of end rings 52, 54, each arranged at one of the axially opposite rotor ends 50-1, 50-2, and each of the pair of end rings 52, 54 can define a gas inlet 108. Furthermore, the impeller 382 can be arranged and configured in the at least one fluid channel 68, e.g., the central channel 104 of the rotor 24, to pump the gas 72 and the liquid 70 into the air gap 14 and thereby directly cool the rotor 24.

[0044] As in Fig. As shown in Figure 12, the impeller 382 can, for example, be star-shaped and contain a plurality of blades 84. The impeller 382 can be arranged between at least one of the plurality of vanes 58 and stacked against them, and can operate as a pump to distribute gas 72 and liquid 70 to the air gap 14 for cooling the electric motor 10.

[0045] That is, how best to refer to Fig. As described in Figure 11, during operation of the electric motor 10, the gas 72 can circulate around each of the two end rings 52, 54, through the gas inlet 108 of each of the two end rings 52, 54, and through the majority of the magnet slots 16 by means of centrifugal force, thereby directly cooling the majority of the magnets 60. For example, the liquid 70 and the gas 72 can enter the rotor 24 from the sump 80 or the inlet, flow through the passage 78 of the shaft 74 to the at least one fluid channel 68, and encounter the impeller 382. The impeller 382 can pump the liquid 70 and the gas 72 to the air gap 14. The liquid 70 and the gas 72 can migrate through the air gap 14 and around the end rings 52, 54 of the rotor 24, whereby the gas 72 can re-enter the rotor 24 through the gas inlet 108 of each respective end ring 52, 54 in order to migrate back to the at least one fluid channel 68 and continue to circulate.As such, the rotor 24 can be cooled by the liquid 70 and the gas 72 by means of air gap cooling, and the majority of the magnets 60 can be cooled by the gas 72 by means of magnetic slot cooling.

[0046] Referring to Fig. 13 In another embodiment, the impeller 482 can be arranged in the at least one fluid channel 68, e.g., the central channel 104 of the rotor 24. As in Fig. As best illustrated in Figure 14, the impeller 482 can comprise a plurality of blades 84 and a fluid bridge 110 arranged between two adjacent blades of the plurality of blades 84. The fluid bridge 110 can be configured to direct fluid 70 from the at least one fluid channel 68 to the air gap 14 to directly cool the rotor 24, and to the plurality of magnet slots 16 to directly cool the plurality of magnets 60.

[0047] Furthermore, referring again to Fig. 13, in this embodiment each of the two end rings 52, 54 has a gas inlet 108, which is designed to introduce the gas 72 through the end ring 52, 54, and a liquid outlet 112, which is designed to guide the liquid 70 from the majority of the magnetic slots 16 through the end ring 52, 54, wherein again Fig. 13. Reference is made to this.

[0048] Therefore, as further referenced in the Fig. 13 and Fig. As described in Figure 14, during the operation of the electric motor 10, the liquid 70 and the gas 72 enter the rotor 24 from the sump 80 or inlet and flow through the passage 78 of the shaft 74 to the at least one fluid channel 68 and encounter the impeller 482. The impeller 482 can pump the gas 72 and a portion of the liquid 70 to the air gap 14. The liquid 70 and the gas 72 can migrate through the air gap 14, and the liquid 70 can exit the rotor 24 at the axially opposite rotor ends 50-1 and 50-2. The gas 72 can move around the end rings 52, 54 of the rotor 24, whereby the gas 72 can re-enter the rotor 24 through the gas inlet 108 of each respective end ring 52, 54 in order to return to the at least one fluid channel 68 and continue circulating there. The liquid 70 can also flow from the impeller 482 through the majority of the magnet slots 16 and exit each end ring 52, 54 through the respective liquid outlet 112.Thus, the rotor 24 can be cooled by the liquid 70 and the gas 72 using air gap cooling, and the majority of the magnets 60 can be cooled by the liquid 70 using magnetic slot cooling.

[0049] With reference to Fig. 15 and Fig. 16 In another embodiment, the impeller 582 can have a stacked configuration. That is, the majority of the lamellae 58 can form two bridge lamellae 158 ( Fig. 16) comprising, which are arranged next to and in contact with the impeller 582, wherein each of the two bridge lamellae 158 is designed to minimize the injection of the fluid 70 from the at least one fluid channel 68 into the air gap 14.

[0050] For example, the wheel 582 can be used as in Fig. 13 be formed and arranged in at least one fluid channel 68, e.g. the central channel 104 of the rotor 24. As in Fig. As best illustrated in Figure 16, the impeller 582 can comprise the plurality of blades 84 and the fluid bridge 110 arranged between two adjacent blades of the plurality of blades 84. The fluid bridge 110 can be configured to direct fluid 70 from the at least one fluid channel 68 to the air gap 14 to directly cool the rotor 24, and to the plurality of magnet slots 16 to directly cool the plurality of magnets 60. That is, the fluid bridge 110 can direct the fluid 70 to the plurality of magnet slots 16, but in combination with the two bridge lamellae 158, the fluid 70 cannot be directed to the air gap 14. In particular, with reference to Fig. 16 The bridge lamellae 158 can be stacked and layered against the impeller 582 to minimize, reduce or completely prevent the ingress or leakage of the liquid 70 into the air gap 14.

[0051] Therefore, as further referenced above Fig. As described in Figure 15, during the operation of the electric motor 10, the liquid 70 and the gas 72 enter the rotor 24 from the sump 80 or inlet, flow through the passage 78 of the shaft 74 to the at least one fluid channel 68, and encounter the impeller 582 stacked between the two bridge lamellae 158. The impeller 582 and the bridge lamellae 158 can pump the gas 72 to the air gap 14. The gas 72 can flow through the air gap 14 around the end rings 52, 54 of the rotor 24, whereby the gas 72 can re-enter the rotor 24 through the gas inlet 108 of each respective end ring 52, 54 to flow back to the at least one fluid channel 68 and continue to circulate. The fluid 70 can flow from the impeller 582 through the majority of the magnet slots 16 and exit each end ring 52, 54 through the respective fluid outlet 112.In this way, the rotor 24 can be cooled by the gas 72 using air gap cooling and the majority of the magnets 60 by the liquid 70 using magnetic slot cooling.

[0052] Referring to Fig. In another embodiment, the rotor 24 comprises an end ring 54, which is designed as an impeller 182 and is arranged at one of the axially opposite rotor ends 50-2. At the other axially opposite rotor end 50-1, the end ring 52 can define the fluid outlet 112. Furthermore, the rotor 24 can comprise the plurality of lamellae 58, which are stacked side by side to define the at least one fluid channel 68, which extends from the shaft 74 to the radially inner rotor core surface 64. That is to say, as a non-limiting example, the plurality of lamellae 58 can be shaped as shown in Fig. Figure 17 shows how to direct the fluid 70 from the at least one fluid channel 68 to the plurality of magnetic slots 16. Therefore, the end ring 54, including the impeller 182, can pump the gas 72 to the plurality of magnetic slots 16 and to the air gap 14, and the plurality of lamellae 58 can direct the fluid 70 to the plurality of magnetic slots 16 without directing the fluid 70 to the air gap 14.

[0053] As with continued reference to Fig. As described in Figure 17, during operation of the electric motor 10, the liquid 70 and the gas 72 can enter the rotor 24 from the sump 80 or the inlet and flow through the passage 78 of the shaft 74 to the at least one fluid channel 68, which is defined by the plurality of vanes 58. The end ring 54, including the impeller 182, can pump the gas 72 into the plurality of the magnetic slots 16. The liquid 70 and the gas 72 can migrate through the plurality of the magnetic slots 16, and the gas 72 can migrate through the plurality of the magnetic slots 16 to the air gap 14. The liquid 70 and the gas 72 can exit the rotor 24 at the liquid outlet 112. The gas 72 in the air gap 14 can migrate around the end rings 52, 54 of the rotor 24, and the gas 72 can re-enter the rotor 24 through the gas inlet 108 of the end ring 54 designed as an impeller 182 and continue to circulate.As such, the rotor 24 can be cooled by the gas 72 via air gap cooling, and the majority of the magnets 60 can be cooled by the liquid 70 and the gas 72 via magnet slot cooling.

[0054] With reference to the electric motor 10, which with reference to the Fig. 2-10 and 13-17, in some embodiments the rotor 24 comprises the fluid circulation arrangement 66 with the at least one fluid channel 68 which extends within the rotor 24 to the radially outer rotor surface 62 and is designed to receive oil and air; to direct the oil by means of centrifugal force into the plurality of the magnetic slots 16; to direct the oil by means of centrifugal force into the plurality of the magnetic slots 16, to direct the air by means of centrifugal force into the air gap 14 and to expel the oil from the plurality of the magnetic slots 16 and the air from the air gap 14 at the axially opposite rotor ends 50-1, 50-2, while the rotor 24 rotates inside the stator 26 in order to cool the electric motor 10.

[0055] In summary, it can be said that in each embodiment described herein, gas 72 can flow in the air gap 14 (see e.g. Fig. 3, Fig. 7, Fig. 11, Fig. 13 and Fig. 17), but also in the majority of the magnetic slots 16 (see e.g. Fig. 7, Fig. 11 and Fig. 17) can flow. Furthermore, the liquid 70 can flow in the majority of the magnetic slots 16 (see e.g. Fig. 3, Fig. 7, Fig. 15 and Fig. 17), but also in the air gap 14 (see e.g. Fig. 7, Fig. 11 and Fig. 13). Furthermore, liquid 70 and / or gas 72 can be conveyed within the rotor 24 via an impeller 82, 182, 282, 382, ​​482, 582 (see e.g. Fig. 3, Fig. 7, Fig. 11 and Fig. 17) or without the use of a wheel 82 (see e.g. Fig. 13 and Fig. 15) flow.

[0056] In summary, the electric motor 10 and the vehicle 12 can exhibit excellent operating efficiency. This means that coolant, e.g., liquid 70 and / or gas 72, can be injected or pumped directly into the air gap 14 and / or the majority of the magnetic slots 16 to dissipate the heat energy generated by the electric motor 10 during operation. Furthermore, the electric motor 10 described herein can minimize efficiency losses, i.e., rotational losses, during rotation about the axis of rotation 22, which could otherwise be caused by unwanted fluid leakage. In addition, the electric motor 10 can have a lower mass and complexity and be manufactured with improved efficiencies. For example, as described above, the impeller 282 can be cast directly into the end ring 52, 54, thereby reducing the manufacturing costs of the electric motor 10.As such, the electric motor 10 can improve the fuel consumption of the vehicle 12.

[0057] The embodiments described in this disclosure are intended to serve as non-limiting examples, and other embodiments may take various and alternative forms. Furthermore, the accompanying drawings are not necessarily to scale and may represent a somewhat simplified depiction of various features of this disclosure, including, for example, certain dimensions, orientations, positions, and shapes. Details associated with such features are partly determined by the intended application and the operating environment of the described embodiments.

[0058] For the purposes of this description, the use of the singular includes the plural and vice versa, unless expressly omitted. The terms "and" and "or" apply in both the subjunctive and disjunctive moods, and the words "including," "containing," "comprising," "having," and the like mean "including without limitation." Furthermore, words of approximation such as "approximately," "essentially," "generally," "about," etc., may be used here to mean "at, close to, or almost at" or "within 0-5% of" or "within acceptable manufacturing tolerances," or logical combinations thereof. A component "designed" to perform a particular function is capable of performing the specified function without modifications, and not merely has the potential to perform the specified function after further modifications.In other words, if the described hardware is explicitly designed to perform the specified function, it is specifically selected, created, implemented, used, programmed, and / or designed for performing that function. Furthermore, the use of ordinal numbers such as "first," "second," and "third" does not necessarily imply an ordered sequence but merely serves to distinguish between multiple instances of an action or structure.

[0059] The detailed description and the drawings or figures are supporting and descriptive of the present teaching, but the scope of the present teaching is defined exclusively by the claims. While some of the best modes and other embodiments for carrying out the present teaching have been described in detail, there are various alternative designs and embodiments for carrying out the present teaching, which are defined in the appended claims. Furthermore, this disclosure expressly includes combinations and subcombinations of the elements and features shown above and below.

Claims

[1] An electric motor comprising: a stator with a radial inner stator core surface; and a rotor which is mounted inside the stator and is rotatable about an axis of rotation, wherein the rotor has: axially opposite rotor ends; a radial outer rotor surface extending between the axially opposite rotor ends and positioned close to the radial inner stator core surface to define an air gap between them; and a radial inner rotor surface spaced apart from the radial outer rotor surface to define a plurality of magnet slots between them, each configured to receive one of a plurality of magnets therein; wherein the rotor has a fluid circulation arrangement with at least one fluid channel extending within the rotor to the radially outer rotor surface and configured to receive a liquid and a gas, to direct at least one of the liquid and the gas by means of centrifugal force into the plurality of magnetic slots, to direct at least another of the liquid and the gas by means of centrifugal force into the air gap, and to expel the liquid and the gas from the plurality of magnetic slots and the air gap at the axially opposite rotor ends when the rotor rotates in the stator in order to cool the electric motor. [2] The electric motor according to claim 1, furthermore, with a shaft arranged along the axis of rotation; wherein the rotor has a radially inner rotor core surface which is arranged in contact with the shaft and spaced apart from the radially outer rotor surface; and wherein the at least one fluid channel extends through the rotor from the radially inner rotor core surface to the radially outer rotor surface. [3] The electric motor according to claim 2, further comprising an impeller arranged within the at least one fluid channel and rotatable about the axis of rotation. [4] The electric motor according to claim 3, wherein the impeller is configured to separate the liquid and the gas, to pump the gas into the air gap in order to directly cool the rotor, and to inject the liquid into the majority of the magnet slots in order to directly cool the majority of the magnets. [5] Electric motor according to claim 3, wherein the impeller has a blade arranged between a first cover and a second cover. [6] The electric motor according to claim 5, wherein the rotor is formed from a plurality of stacked lamellae; and furthermore, the impeller is embedded between two adjacent plural lamellae in order to define an air path from the radially inner rotor core surface to the air gap and a fluid path from the radially inner rotor core surface to the plurality of magnetic slots. [7] The electric motor according to claim 2, wherein the rotor further has a pair of end rings, each designed as an impeller and arranged at one of the axially opposite rotor ends; wherein the at least one fluid channel extends along each of the end rings through the plurality of magnetic slots from the radial inner rotor surface to the radial outer rotor surface and through the air gap; and wherein the pair of end rings pumps the liquid and gas from the axially opposite rotor ends into the plurality of magnet slots in order to directly cool the plurality of magnets. [8] The electric motor according to claim 7, wherein the rotor is formed from a plurality of stacked lamellae; wherein the plurality of lamellae comprises a first central lamella and a second central lamella which is layered onto the first central lamella; and wherein the first central lamella and the second central lamella are formed together to guide the liquid and the gas into the air gap. [9] Electric motor according to claim 8, wherein the at least one fluid channel is designed to receive the liquid and the gas from the plurality of magnetic slots and to guide the liquid and the gas into the air gap by means of centrifugal force in order to expel the liquid and the gas from the air gap at the axially opposite rotor ends when the rotor rotates inside the stator in order to cool the electric motor. [10] A vehicle comprising: an electric motor designed to generate torque for propelling the vehicle, the electric motor comprising: a stator with a radial inner stator core surface; and a rotor which is mounted inside the stator and is rotatable about an axis of rotation, wherein the rotor has: axially opposite rotor ends; a radial outer rotor surface extending between the axially opposite rotor ends and positioned close to the radial inner stator core surface to define an air gap between them; and a radial inner rotor surface spaced apart from the radial outer rotor surface to define a plurality of magnet slots between them, each configured to receive one of a plurality of magnets therein; wherein the rotor has a fluid circulation arrangement with at least one fluid channel extending within the rotor to the radial outer rotor surface and configured to receive a liquid and a gas, to guide at least one of the liquids and the gas by means of centrifugal force into the plurality of magnetic slots, to guide at least another of the liquid and the gas by means of centrifugal force into the air gap, and to expel the liquid and the gas from the plurality of magnetic slots and the air gap at the axially opposite rotor ends when the rotor rotates within the stator in order to cool the electric motor.

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