Electrical machine with a stator arrangement and immersion cooling system

Abstract

Stator arrangement, comprising: a stator core that interlocks with a stator sleeve at an interface; wherein the interface comprises a first section that forms an interference fit between the stator core and the stator sleeve; and a fastening device that holds the stator core axially in the stator sleeve; wherein the stator sleeve includes a coolant deflector profiled to direct coolant through stator windings and into one or more coolant channels extending through the stator core from an inlet-side coolant chamber to an outlet-side coolant chamber.

Description

TECHNICAL AREA

[0001] The present disclosure relates to an electric machine with a stator arrangement and an immersion cooling system for stator windings. BACKGROUND AND DETOUR

[0002] Some electric motors use cooling systems to increase motor efficiency. For example, water jackets surrounding the motor housing are used to cool certain motors. Other motors have attempted to cool the stator with coolant directed closer to the stator to increase the amount of heat that can be dissipated from it.

[0003] US 10,770,934 B2 by Jakob et al. discloses an electric machine with cooling channels formed between a housing sleeve and a stator sleeve. The liquid cooling medium in the channels can be water, oil, or air. The electric machine additionally features a Hirth face gear to create a rigid connection between the housing sleeve and the stator sleeve.

[0004] The inventors identified several problems with the electric machine disclosed by Jacob and other earlier electric machines. For example, they recognized that some vehicle platforms require additional stator cooling. In particular, they recognized that immersion cooling of the winding can be especially effective in further increasing the motor's efficiency. However, in practice, integrating immersion cooling into electric machines can present challenges regarding packaging, ease of maintenance, and repair. For instance, integrating immersion cooling into certain electric machines may involve compromises in cooling performance and ease of maintenance.

[0005] The inventors recognized the aforementioned problems and developed a stator arrangement for an electric machine to address them, at least in part. In one example, the stator arrangement comprises a stator core connected at an interface to a stator sleeve, which includes a first section forming an interference fit between the stator core and the stator sleeve. The stator arrangement further includes a fastening device that axially secures the stator core within the stator sleeve. Additionally, the stator sleeve in the stator arrangement includes a coolant deflector profiled to direct coolant through the stator windings and into one or more coolant channels extending from an inlet to an outlet through the stator core. Cooling through the stator windings significantly increases the cooling efficiency compared to other motors, such as water jacket motors.Furthermore, the use of the press-fit interface and the mounting device allows the stator to be designed conceptually as a cartridge. This improves assembly, ease of maintenance, and repair.

[0006] In one example, the interface includes a second section that forms a clearance fit between the stator core and the stator sleeve. By using a clearance fit and an interference fit at the interface between the stator core and the stator sleeve, the stator assembly can be efficiently removed from an electrical machine (which is installed in the assembly) for maintenance or repair work. Designing the interface with the interference fit only along a portion of the interface reduces the comparatively higher stresses caused by strong pressing forces on the stator. Furthermore, the fastening device (e.g., a lock nut) allows for secure fixation of the stator core in the sleeve under lower stress. This reduces the likelihood of deterioration of the stator assembly.

[0007] In another example, the stator sleeve can have one or more O-ring recesses profiled to accommodate O-rings designed to form a seal between the stator sleeve and the housing of the electric machine. The O-ring recesses and O-rings prevent a coolant short circuit between the crown end and the weld end of the windings. Furthermore, the O-ring recesses and O-rings also serve as protection against the ingress of external fluids. Additionally, during operation, the O-ring recesses and O-rings act as bump stops, reducing noise, vibration, and harshness (NVH) during the operation of the electric machine.

[0008] It should be noted that the above summary serves to present a selection of concepts in simplified form, which are further explained in the detailed description. It does not serve to identify essential features of the claimed subject matter, the scope of which is clearly defined by the claims following the detailed description. Furthermore, the claimed subject matter is not limited to implementations that overcome all the disadvantages mentioned above or in any part of this disclosure. BRIEF DESCRIPTION OF THE FIGURES Fig. Figure 1 is a representation of an exemplary electrical machine that includes an immersion cooling system. Fig. Figure 2 is a detailed cross-sectional view of an electric machine with a stator arrangement and an immersion cooling system for the stator arrangement. Fig. Figure 3 is a representation of another exemplary electrical machine that includes an immersion cooling system. Fig. Figures 4-5 are detailed views of a stator core and stator windings in the [context missing]. Fig. 3 immersion cooling systems shown. Fig. Figures 6-12 are different views of another example of an immersion cooling system. DETAILED DESCRIPTION

[0009] This section describes electric machines with stator configurations that function conceptually as cartridges and are equipped with a cooling function for the immersed ends of the windings. The stator cartridge enables efficient assembly, maintenance, and repair of the machine and can be effectively integrated into the stator cooling system. This increases the efficiency and service life of the electric machine because heat is dissipated from the stator more effectively than with certain motor cooling systems that use water jackets around the motor housing. Furthermore, the immersion cooling of the windings allows for increased machine efficiency.To achieve these properties, the stator assembly can include a stator core fitted into a stator sleeve via an interface comprising an interference fit section and a clearance fit section to reduce stresses caused by the high pressing forces, as shown in an example. The stator assembly further includes a fastening device (e.g., a lock nut) that secures the stator core to the stator sleeve. Specifically, the fastening device allows a clamping force to be applied to the stator core, securely fixing it within the sleeve with reduced radial stress caused by the pressing forces between the stator sleeve and the stator core. By reducing compressive stresses, the magnetic performance and service life of the electric machine can be increased compared to machines with a higher degree of interference fit between the parts.Furthermore, reducing the compressive stress in the stator assembly simplifies its manufacturing. In one embodiment, the immersion cooling system comprises a coolant inlet at a crown end of the stator and a coolant outlet at the weld end of the stator assembly. The cooling system utilizes a coolant diverter in the stator sleeve to effectively direct the coolant through the end windings. The stator sleeve may also feature O-ring recesses designed to form a seal between the stator sleeve and the housing of the electric machine. This prevents an undesirable coolant leakage path between the stator end windings on each axial side of the stator and reduces the likelihood of external fluid ingress.The O-rings have a dual function, as they also serve as stop buffers, thus reducing noise, vibration and roughness (NVH) that can be caused, for example, by contact between a flange and a support during machine operation.

[0010] Fig. Figure 1 shows an example of an electric machine 100 that may be included in a system 102, for example, an electric vehicle (EV) or another suitable system. In the example of an electric vehicle, the electric machine may be a traction motor in an electric drive. Thus, the electric vehicle may be a pure electric vehicle or a hybrid electric vehicle (HEV) with an internal combustion engine. However, it should be understood that the electric machine 100 can be used in a wide variety of fields, including, but not limited to, industrial machinery, agricultural systems, mining systems, and the like.

[0011] The electric machine 100 comprises a stator assembly 104 and a rotor assembly 106. The electric machine 100 further comprises a cooling system 108 (e.g., an immersion cooling system) for the stator assembly 104. The cooling system 108 includes a pump 110 that draws coolant (e.g., oil) from a coolant outlet 112 in the stator assembly 104 and delivers coolant to a coolant inlet 114 in the stator assembly 104. Connections such as fittings can be used to fluidically connect coolant lines 116 to the pump 110. However, other coolant line configurations in the cooling system are also possible. The coolant inlet and outlet are located in areas around opposing stator windings. Details of the immersion cooling system and the stator assembly are described here with reference to Fig. 2 explained in more detail.

[0012] The cooling system 108 may also include a filter, valves, and the like. Furthermore, in the example shown, the pump 110 is positioned outside the electric machine 100. However, it is understood that the pump 110 can be integrated into the electric machine in different configurations or coupled to a housing of the electric machine.

[0013] In the example of the electric vehicle, an inverter 118 can be electrically coupled to the electric machine 100 via electrical connection devices 121 such as wires, cable harnesses, busbars, combinations thereof, and the like. The inverter 118 can also be electrically connected to an energy storage device 120 (e.g., one or more traction batteries, capacitors, fuel cells, combinations thereof, and the like) via electrical connection devices 123, such as wires, cable harnesses, busbars, combinations thereof, and the like. Therefore, during drive operation and regeneration operation, electrical energy can flow between the inverter and the energy storage device if the electric machine 100 is configured as a motor-generator.

[0014] The electric drive 100 can be coupled with downstream components 128. In the EV example, the downstream components 128 can include one or more drive axles, drive wheels, and the like.

[0015] The electric drive 100 can further comprise a control system 190 with a control unit 192, as shown in Fig. Figure 1 illustrates the control unit 192, which may include a microcomputer with components such as a processor 193 (e.g., a microprocessor unit), input / output ports, and an electronic storage medium 194 for executable programs and calibration values ​​(e.g., a read-only memory chip, a read-only memory, a diagnostic memory, a data bus, and the like). The storage medium may be programmed with computer-readable data representing instructions that can be executed by a processor to perform the procedures and control techniques described herein, as well as other variations that are expected but not specifically listed. Control techniques, procedures, and the like described herein may be stored as instructions in non-volatile memory.

[0016] The control unit 192 can receive various signals from sensors 195, which are coupled to different areas of the electric machine 100 and the system 102 in general. For example, the sensors 195 can include a rotor current sensor, an electric machine speed sensor, a stator current sensor, an electric machine temperature sensor, a battery charge level sensor, an inverter current sensor, and the like. The speed of the electric machine can be determined from the power supplied to the electric machine 100 by the inverter 118. An input device 198 (e.g., accelerator pedal, brake pedal, drive mode selector, gear selector, combinations thereof, and the like in the EV example) can also provide input signals indicating the driver's intention to control the electric drive.

[0017] After receiving the signals from the various sensors, 195 of Fig. 1. The controller 192 processes the received signals and uses various actuators 196 of the electric drive components to adjust the components based on the received signals and the instructions stored in the controller 192's memory. For example, the controller 192 can receive a signal indicating an operator request to increase the power output of the electric machine. In response, the controller 192 can instruct the inverter 118 to adjust the mechanical power output of the electric machine and increase the power delivered by the electric machine 100 to downstream components 128. The other controllable components in the electric drive can operate similarly with respect to sensor inputs and command outputs. For example, the pump 110 can be controlled in a similar manner to drive the coolant flow through the cooling system 108.A detailed example of a cooling system for a stator assembly is in . Fig. 2 is shown and is explained in more detail here.

[0018] In Fig. 1 and Fig. Figure 2 shows a coordinate system for reference. In one example, the z-axis can be a vertical axis (e.g., parallel to a gravitational axis), the x-axis can be a lateral axis (e.g., a horizontal axis), and the y-axis can be a longitudinal axis. In other examples, the axes may have different orientations.

[0019] Fig. Figure 2 shows an example of an electric machine 200 with a stator arrangement 202. The in Fig. Figure 2 shows an electric machine 200, which serves as an example for the one shown in Figure 2. Fig. 1. The depicted electric machine 100. The sectioning plane for the in Fig. The cross-sectional view shown in section 2 passes through an axis of rotation of the electric machine.

[0020] The stator assembly 202 comprises a stator core 204, which is at least partially enclosed circumferentially by a stator sleeve 206. In the illustrated example, the stator sleeve 206 includes a body 208. The stator core 204 is pressed into the interior of the stator sleeve 206. To explain in more detail: The stator core 204 and the stator sleeve 206 form an interface 209 at an inner surface 210 of the sleeve and an outer surface 212 of the core. In the illustrated example, one section 214 of the interface 209 is formed by an interference fit and another section 216 of the interface by a clearance fit. In this way, the pressing forces on the stator can be reduced, thereby increasing the service life of the stator assembly. More precisely, section 214 of interface 209 is positioned next to a crown side 218 of the stator assembly and is therefore spaced apart from a weld side 220 of the stator assembly.Section 216 is therefore positioned next to the weld side 220. The axial length 222 of section 216 can be greater than the axial length 224 of section 214. However, other relative sizes of the sections were also considered.

[0021] In the illustrated example, the stator sleeve 206 includes a flange 226 that extends radially outward from the body 208 of the sleeve. The flange 226 can be specifically arranged on the weld side 220 and comprises an inner surface 228 and an outer surface 230. When the stator assembly 202 is installed in the electric machine, the flange 226 is connected to a housing of the electric machine. The flange 226 enables efficient integration of the stator assembly into the electric machine. An exemplary housing for an electric machine connected to a stator sleeve flange is shown in Fig. Figure 3 is shown and explained in more detail below. Alternatively, the flange on the stator sleeve can be omitted.

[0022] In the Fig. In the example shown, the stator sleeve 206 further comprises a coolant deflector 232, which increases the coolant flow through and around the stator windings 240, thereby improving the cooling and efficiency of the electric machine. In the example shown, the coolant deflector 232 is detachably connected to the body 208 by means of a deflector fastening device 234 (e.g., a rivet, a screw, combinations thereof, and the like). In particular, a section 236 of the coolant deflector 232 can overlap a section 238 of the sleeve body 208, and the deflector fastening device 234 can extend through these overlapping sections. In another example, however, the coolant deflector 232 and the body 208 can form a continuous structure and therefore be made of the same material.To clarify: The sleeve body 208 and the coolant deflector 232 can be made of steel or another suitable metal in a specific example.

[0023] In another example, if the coolant deflector 232 is detachably attached to the sleeve body 208, the body can be made of steel or another suitable metal, and the coolant deflector 232 can be made of plastic. Making the deflector from plastic reduces the weight of the stator assembly compared to making the deflector from metal. In yet another example, the coolant deflector 232 can be injection-molded onto the sleeve body 208. In such an example, the deflector 232 can again be made of plastic, and the sleeve body 208 can be made of steel or another suitable metal.

[0024] The coolant deflector 232 comprises a wall 239 that extends around the stator windings 240, thereby at least partially enclosing the end windings. An opening 242 extends (e.g., axially) through the wall 239. This opening 242 allows the coolant to achieve the desired flow dynamics to improve the cooling of the end winding, as explained in more detail below.

[0025] The stator assembly 202 comprises an immersion cooling system 244 with a coolant chamber 246 on the inlet side and a coolant chamber 248 on the outlet side. The coolant chamber 246 on the inlet side can receive coolant from a pump 250 at an inlet port 252. Coolant lines 254, pipes, combinations thereof, and the like can be used to fluidically connect the pump 250 and the inlet port 252. The coolant chamber 248 on the outlet side can be in fluidic communication with the pump 250 via an outlet port 256 using coolant lines 258, channels, combinations thereof, and the like. The working fluid in the immersion cooling system 244 can be oil to avoid undesirable electromagnetic interactions between the fluid and the windings compared to systems using a water-based coolant.

[0026] In the illustrated example, the coolant immerses the end windings 240. More precisely, in a region 260 outside the coolant deflector 232, the coolant is directed through the opening 242 into a region 262 around the end windings 240. The arrows 263 indicate the general direction of coolant flow through the immersion cooling system 244. However, it is understood that the coolant flow can be more complex in practice. The opening 242 forces the coolant to flow through the crown-side end windings 240 instead of flowing directly to the coolant channels 266. The coolant then flows through the end windings 240 and into the inlets 264 of the coolant channels 266, which traverse the stator core 204 axially. The outlets 268 of the coolant channels 266 open into the outlet-side coolant chamber 248. Coolant flows from the outlets 268 through and around the end windings 270.By routing the coolant through the stator arrangement 202 as described above, a larger amount of heat can be dissipated from the end windings and the stator core, thereby increasing the power of the electric machine.

[0027] A fastening device 272 (e.g., a lock nut, which may have external threads 274) is attached to the stator sleeve 206 and allows a clamping force to be applied to the stator core 204. The external threads 274 engage in internal threads 276 on a section of the inner surface 210 of the stator sleeve 206. The use of the fastening device 272 allows only a portion of the interface 209 at its deep end to have an interference fit, thereby reducing stresses at the interface between the sleeve and the core and increasing the service life of the stator assembly. By reducing these stresses, the magnetic performance and durability of the stator assembly can be increased, and the design of the stator assembly can be simplified. Furthermore, the fastening device 272 allows the stator sleeve 206 to be detachably fastened to the stator core 204.

[0028] An outer surface 278 of the stator sleeve 206 includes O-ring recesses 280 profiled to accommodate O-rings 282. The O-rings 282 form a seal with the electrical machine housing to prevent coolant from flowing through a shortcut between the crown-side and weld-side windings. The sleeve body 208 can have a thinner section near the center and thicker sections near the axial ends to allow the O-ring recesses 280 in the outer surface to be formed with a desired profile. However, other body shapes have also been considered. The O-rings 282 can also act as stop buffers to reduce NVH (noise, vibration, and harshness) that can arise from the flange 226 contacting the inner walls of a support. Thus, the O-rings 282 can function as noise dampers.Furthermore, compensating plates 284 can be attached to opposite axial sides of the stator core 204. In other embodiments, however, the compensating plates 284 can be omitted from the stator arrangement 202.

[0029] Fig. Figure 3 shows another example of an electric machine 300 with a stator arrangement 302, which uses immersion cooling for the crown-side end windings 304 and the crown-side end windings 306. The electric machine 300 can incorporate at least some of the components and features of the one shown in Fig. The electrical machine shown comprises 200 units. For the sake of simplicity, redundant descriptions of overlapping components, features, etc., have been omitted.

[0030] The walls 308 form a boundary of a crown-side coolant chamber 310 for winding cooling. For clarification: An outer circumferential section 340 and an inner circumferential section 342 at least partially enclose the crown-side windings 304 and a fastening device 338, which are explained in more detail herein. In particular, in the illustrated example, the outer circumferential section 340 is in surface contact with a crown side 344 of a stator core 317. Furthermore, in the illustrated example, the inner circumferential section 342 is in sealing contact with an inner diameter of one of the compensating plates 321. In other embodiments, however, the coolant chamber on the crown side can be bounded by a different suitable cooling system architecture.

[0031] In the illustrated example, a coolant inlet 311 supplies coolant to the coolant chamber 310 on the crown side. Arrows 313 indicate the general direction of coolant flow from the coolant inlet 311 to the coolant channels 315 in the stator core 317. In this way, the coolant flow on the outside of a deflector 352 is efficiently directed to the crown-side end windings 304 to improve cooling. Furthermore, the walls 312 form a boundary of a weld-side coolant chamber 314. An inner circumferential section 348 of the walls 312 can be in sealing contact with one of the compensating plates 321, and a radially extending section 350 of the walls 312 can extend along the coolant deflector 352 and be in sealing contact with a section of a support housing 326. Furthermore, a gap 353 can be formed between the radially extending section 350 and the deflector 352 to allow coolant to flow through it.Seals for coolant chambers on both the crown side and the weld side are explained in more detail here.

[0032] An outlet 319 can be in fluidic communication with the weld-side coolant chamber 314. The outlet 319 can be in fluidic communication with a coolant pump via a sump or be directly fluidically coupled to the pump. Furthermore, the weld-side coolant chamber 314 and the crown-side coolant chamber 310 are in fluidic communication with each other via coolant channels 315, which, in the illustrated example, extend axially through the stator core. For further explanation: The coolant channels 315 can extend axially through the stator core 317 and the compensating plates 321.

[0033] The stator assembly 302 in turn comprises the stator core 317, which is at least partially fitted into a stator sleeve 318. Here, too, an interface is formed between the stator core 317 and the sleeve 318, where one section 320 fits with a clearance fit and another section 322 fits with an interference fit, similar to the one in Fig. 2 depicted electric machine.

[0034] Seals 324 can be provided for the weld-side coolant chamber 314. To clarify: One of the seals 324 can be provided between one of the walls 312 and the support housing 326, and another of the seals 324 can be provided between one of the leveling plates 321 and the walls 312. Seals 325 can be provided for the crown-side coolant chamber 310 to seal one of the leveling plates 321 and the support housing 326.

[0035] Seals 328 can be provided on the outer diameter of the stator sleeve 318 and the support housing 326. A triangular O-ring 330 can also be provided in the interface between the stator sleeve 318 and the support housing 326 to seal and stiffen the interface. Alternatively, the triangular O-ring 330 can be omitted, which, however, may reduce the stiffness of the stator assembly.

[0036] In the illustrated example, a flange 332 in the stator sleeve 318 is connected to a flange 334 in the support housing 326 via fastening devices 336. A fastening device 338 (e.g., a lock nut) is used again to fasten the stator sleeve to the stator core, similar to the one in Fig. The electric machine shown in Figure 2 is described below. For the sake of clarity, a redundant description of the overlapping features is omitted. Fig. Figure 3 further shows a rotor 360 with an air gap 362 between the rotor 360 and the stator core 317. The section plane for the in Fig. The cross-sectional view shown in Figure 3 passes through an axis of rotation of the electric machine, similar to that in Figure 3. Fig. 2.

[0037] The Fig. 4 and Fig. Figure 5 shows a detailed view of the stator core 317 with the end windings 304 and 306 on the crown side and weld side of the stator, respectively. The coolant channels 315 are also shown running axially between the crown side and the weld side of the stator. The compensating plates 321 are shown in the Fig. 4-5 shown in more detail.

[0038] The Fig. 6 and Fig. Figure 7 shows a stator sleeve 600 and a stator core 700, respectively, which are included in another example of a stator arrangement. It is understood that the components shown in the Fig. Stator arrangement shown in 6-7 in each of the Fig. The stator sleeve 600 may be included in the electrical machines shown in Figures 1-3 or in combinations of such machines. The stator sleeve 600 comprises an inner surface 602 with several tabs 604 extending axially along the interior of the sleeve. The tabs 604 extend radially inward in the direction of the axis of rotation of the machine and may have side surfaces and a surface extending between the side surfaces, as explained in more detail herein. Dampers 605 may be arranged on the tabs and between the tabs and the recesses 702 in the stator core during assembly. In particular, the dampers 605 are in surface contact with the surfaces of the tabs in the illustrated example.

[0039] The 605 dampers reduce vibrations by compressing the damping material, compensating for mechanical tolerances and reducing mechanical stress, thereby extending the machine's service life. The 605 dampers and the other dampers described here can be made from a material with lower stiffness than metal, such as plastic or elastomer.

[0040] The tabs 604 can, for example, be arranged at equal intervals around the inner circumference of the sleeve. However, tabs with unequal spacing were also considered. When the stator is assembled, the tabs 604 interlock with several recesses 702, which are located in the Fig. The stator core 700 shown in Figure 7 is provided with recesses 702. Thus, the recesses 702 in the stator core extend axially along an outer surface 704 of the stator core. In some embodiments, the stator sleeve 600 may also include a flange 606 for attaching the flange to other components in the assembly. Sections 608 and 610 in the stator sleeve can form gaps between the sleeve and the stator core when assembled. This allows the sleeve to mesh more efficiently with the stator core, simplifying the assembly of the electric machine.

[0041] Fig. Figure 8 shows a perspective view of the dampers 605. In the example shown, the multiple dampers 605 are connected by rings 800, which are positioned on opposite sides of the dampers. In this way, the dampers can be efficiently installed in the sleeve. However, alternative damper configurations were also considered.

[0042] Fig. Figure 9 shows a detailed cross-sectional view of part of the interface formed between the stator sleeve 600 and the stator core 700. The section plane for the Fig. The cross-sectional view shown in Figure 9 passes through the axis of rotation of the electric machine and is arranged perpendicular to it. One of the lugs 604 and one of the dampers 605 are in Fig. 9 shown.

[0043] In the Fig. In the example shown, the side walls 900 of the damper 605 are in planar contact with a side surface 902 of the recess 702. A free space 904 is formed between a wall 906 of the damper 605, which extends between the side walls 900. A further free space 908 is formed between an outer surface 910 of the stator core 700 and an inner surface 912 of the stator sleeve 600.

[0044] In one example, the side walls 900 of the damper can form an angle 913 with respect to a radial axis 915 that is less than 90°. However, side walls with other contours are also conceivable.

[0045] The dampers described here reduce the likelihood of metal-to-metal contact between the stator sleeve and the stator core. This allows the stator core to float within the stator sleeve, thereby increasing the service life of the stator assembly by reducing unwanted metal-to-metal contact between the stator components.

[0046] Fig. Figure 10 shows another cross-sectional view of the stator sleeve 600 and the stator core 700. A fastening device 1000 (e.g., a lock nut) reattaches the stator sleeve 600 to the stator core 700. The boundary of the in Fig. The detailed view shown in 11 is labeled 1002, and the boundary of the in Fig. The detailed view shown in section 12 is in Fig. 10 is labelled with 1004. Furthermore, the cutting plane for the [unclear text] runs along [unclear text]. Fig. 10. Cross-sectional view shown, similar to the one in the Fig. 2 and Fig. 3 through a rotational axis of the electric machine.

[0047] In the Fig. In the example shown in Figure 11, an axial damper 1100 is arranged between the mounting device 1000 and the stator core 700. More precisely, the axial damper 1100 is positioned between a side surface 1102 of the mounting device 1000 and a side surface 1104 of the stator core 700. The axial damper 1100 enables a further reduction in noise, vibration, and roughness characteristics during machine operation, thereby increasing the machine's appeal to the customer and its service life.

[0048] Another axial damper 1200 is in Fig. Figure 12 shows the axial damper 1200 being arranged between a side surface 1202 of the stator core 700 and an inner surface 1204 of the stator sleeve 600. In this way, NVH are further reduced during machine operation. In alternative embodiments, however, at least one of the dampers can be located in the Fig. 11 and Fig. 12 from the stator arrangement are omitted. The ones in the Fig. 11 and Fig. The 12 axial dampers shown dampen the axial movement to further reduce the mechanical stresses in the stator assembly. These axial dampers can be made of plastic or elastomer.

[0049] The cooling systems and stator arrangements described here simplify the maintenance of electric machines, reduce stator stress, improve coolant flow through the stator and stator seal, and reduce noise and vibration during machine operation. This increases their individual appeal.

[0050] Fig. Figures 1-12 show a method for operating a cooling system in a stator assembly. The method involves operating a coolant pump to circulate coolant through an immersion cooling system. More precisely, the coolant flows from the pump to a coolant chamber on the inlet side, through a coolant deflector, and through crown-side end windings to axial coolant channels that traverse a stator core. From the axial channels, the coolant flows into a coolant chamber on the outlet side and from there back to the pump. In this way, a greater amount of heat can be dissipated from the stator assembly, thereby increasing the machine's performance. It is understood that the method can be implemented as instructions stored in memory and executed by a processor of a control unit.

[0051] The technical effect of the cooling system operating method described here is to increase the performance of the electric machine by increasing the amount of heat that can be dissipated from the stator assembly, simplifying the assembly of the stator, and reducing the stresses between a stator sleeve and a stator core, thereby increasing the service life of the stator.

[0052] Fig.Figures 1-12 show example configurations with the relative arrangement of the various components. If these elements are in direct contact with each other or directly coupled, they can be described as being in direct contact or directly coupled, respectively, in at least one example. Similarly, elements shown side by side or adjacent to each other can be described as being adjacent to each other or adjacent to each other, respectively, in at least one example. For instance, components that are in planar contact with each other can be described as being in planar contact. As another example, elements that are separated from each other, with only a gap between them and that have no other components, can be described as such in at least one case.In yet another example, elements that are displayed above / below each other, on opposite sides, or to the left / right of each other can be described as such, relative to one another. Furthermore, in at least one example, as shown in the figures, a topmost element or the highest point of an element can be referred to as the "top" of the component, and a bottommost element or the lowest point of the element can be referred to as the "bottom" of the component. The terms top / bottom, upper / lower, and above / below used here can refer to a vertical axis of the figures and be used to describe the positioning of elements within the figures relative to each other. Thus, in one example, elements displayed above other elements are arranged vertically above the other elements.As a further example, the shapes of the elements depicted in the figures can be described as such (e.g., circular, straight, planar, curved, rounded, beveled, angled, and the like). Furthermore, in one example, elements that are coaxial with each other can be described as such. Additionally, the depicted elements that intersect each other can be described as intersecting elements or mutually intersecting elements in at least one example. Moreover, an element that is depicted inside or outside another element can be described as such. In other examples, elements that are offset from each other can also be described as such.

[0053] The invention is described in more detail in the following paragraphs. In one embodiment, a stator arrangement is provided comprising a stator core connected at an interface to a stator sleeve; wherein the interface comprises a first section forming an interference fit between the stator core and the stator sleeve; and a fastening device that holds the stator core axially in the stator sleeve; wherein the stator sleeve comprises a coolant deflector profiled to direct coolant through the stator windings and into one or more coolant channels extending through the stator core from an inlet-side coolant chamber to an outlet-side coolant chamber. In one example, the coolant deflector can at least partially surround the stator windings. In another example, the coolant deflector can have an opening extending axially through a wall of the coolant deflector.In another example, the interface can include a second section that forms a clearance fit between the stator core and the stator sleeve. In yet another example, the first section can be positioned axially adjacent to the inlet-side coolant chamber. In yet another example, the stator sleeve can have a flange extending radially outward and configured for coupling with an electric machine housing. In yet another example, the flange can be positioned radially outside the coolant chamber on the outlet side. In yet another example, the stator sleeve can have one or more O-ring recesses profiled to accommodate O-rings configured to form a seal between the stator sleeve and an electric machine housing.In another example, the coolant deflector can be connected to the stator sleeve body via a fastening device. In yet another example, the coolant deflector can be made of steel. In another example, the fastening device can be a lock nut. In other examples, the coolant can be oil.

[0054] In a further embodiment, a method for operating a cooling system in a stator assembly is provided, comprising: directing coolant to a coolant inlet in the stator assembly; and flowing coolant through an opening extending through a wall of a coolant deflector that at least partially surrounds stator windings; wherein the stator assembly comprises: a stator core connected to the stator sleeve at an interface comprising an interference fit along a first section of the interface; and a fastening device that holds the stator core axially within the stator sleeve; wherein the stator sleeve comprises the coolant deflector. In an example, the method may further comprise the working fluid flowing from the second winding chamber into a fluid channel extending axially through a rotor shaft.In one example, the interface can include a second section that fits with clearance between the stator core and the stator sleeve and is positioned axially between the mounting device and the first section.

[0055] In a further embodiment, a stator arrangement is provided comprising a stator core connected at an interface to a stator sleeve, which includes: a first section forming an interference fit between the stator core and the stator sleeve; and a second section forming a clearance fit between the stator core and the stator sleeve; a fastening device holding the stator core axially in the stator sleeve; wherein the stator sleeve includes an oil deflector profiled to direct oil through the stator windings and into one or more oil channels extending through the stator core from an inlet-side coolant chamber to an outlet-side coolant chamber; wherein the oil deflector at least partially surrounds the stator windings; and wherein the oil deflector has an opening extending through a wall of the oil deflector.In one example, the second section can be positioned next to the oil inlet. In another example, the stator sleeve can have a flange positioned radially outside the oil outlet and configured to couple to an electric machine housing. In yet another example, the oil deflector is made of plastic, and one part of the stator sleeve body is made of steel. In yet another example, the stator sleeve can have O-ring recesses profiled to accept O-rings configured to form a seal between the stator sleeve and an electric machine housing.

[0056] In a further embodiment, a stator arrangement is provided comprising a stator sleeve connected to a stator core and comprising: several axially extending tabs connected to a plurality of recesses in the stator core; and a fastening device that holds the stator core axially in the stator sleeve; wherein a clearance fit is formed between at least one section of the stator sleeve and the stator core; wherein the stator sleeve comprises an oil deflector profiled to direct oil through the stator windings and into one or more oil channels extending through the stator core from an inlet-side oil chamber to an outlet-side oil chamber; wherein the oil deflector at least partially surrounds the stator windings; and wherein the oil deflector comprises an opening extending through a wall of the oil deflector.In one example, the plurality of axially extending tabs can each include a tab damper made of plastic or elastomer. In another example, the sides of the tab dampers can be in surface contact with the stator core, and a surface extending between the sides can form a clearance fit with the stator core. In yet another example, the stator assembly can further include a first axial damper located between the mounting device and the stator core. In a further example, the stator assembly can further include a second axial damper located between an axial side of the stator core and an inner surface of the stator sleeve.

[0057] In a further embodiment, an immersion cooling system is provided in a stator arrangement. The immersion cooling system comprises an oil deflector contained in a stator sleeve profiled to guide oil through end windings and into axial oil channels traversing a stator core, the stator sleeve being press-fitted to the stator core only at a portion of an interference fit formed between the stator sleeve and the stator core.

[0058] Although various embodiments have been described above, it should be clear that these serve only as examples and do not constitute limitations. Those skilled in the art will recognize that the disclosed subject matter can be implemented in other specific forms without departing from the spirit of the subject matter. The embodiments described above are therefore to be regarded in every respect as illustrative and not as limiting. Thus, the configurations and routines disclosed here are exemplary in nature, and the specific examples are not to be considered limiting, as numerous variations are possible. The technology described above can, for example, be applied to a wide variety of systems that include electric drives with different drive types, including internal combustion engines, such as in a hybrid vehicle.The subject matter of this disclosure includes all novel and non-obvious combinations and sub-combinations of the various systems and configurations, as well as other features, functions and / or properties disclosed herein.

[0059] It should be noted that the example control and estimation routines contained herein can be used with various electric drive and / or system configurations. The control methods and routines disclosed herein can be stored as executable instructions in non-transient memory and can be executed by the control system, including the controller, in combination with the various sensors, actuators, and other electric drive and / or system hardware, in conjunction with the electronic controller. Therefore, the described actions, operations, and / or functions can graphically represent code to be programmed into the non-volatile memory of the computer-readable storage medium in the electric drive and / or system.The various actions, operations, and / or functions shown can be performed in the sequence presented, in parallel, or, in some cases, omitted. Accordingly, the processing sequence is not strictly necessary to achieve the features and benefits of the examples described here; it serves only for better illustration and description. One or more of the actions, operations, and / or functions shown can be executed repeatedly, depending on the specific strategy used. One or more of the procedural steps described here can also be omitted if desired.

[0060] The following claims highlight in particular certain combinations and subcombinations that are to be considered novel and not obvious. These claims may refer to "one" element or "a first" element, or the equivalent thereof. Such claims are to be understood as including one or more such elements, with two or more such elements neither required nor excluded. Other combinations and subcombinations of the disclosed features, functions, elements, and / or properties may be claimed by amending the present claims or by filing new claims in this or a related application. Such claims, whether they have a broader, narrower, the same, or different scope than the original claims, are also to be considered as included in the subject matter of the present disclosure. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] US 10,770,934 B2

[0003]

Claims

[1] Stator arrangement comprising: a stator core that interlocks with a stator sleeve at an interface; wherein the interface comprises a first section that forms an interference fit between the stator core and the stator sleeve; and a fastening device that holds the stator core axially in the stator sleeve; wherein the stator sleeve includes a coolant deflector profiled to direct coolant through stator windings and into one or more coolant channels extending through the stator core from an inlet-side coolant chamber to an outlet-side coolant chamber. [2] Stator arrangement according to claim 1, wherein the coolant deflector at least partially surrounds the stator windings. [3] Stator arrangement according to one of the preceding claims, wherein the coolant deflector has an opening which extends axially through a wall of the coolant deflector. [4] Stator arrangement according to one of the preceding claims, wherein the interface comprises a second section forming a clearance fit between the stator core and the stator sleeve. [5] Stator arrangement according to claim 4, wherein the first section is positioned axially adjacent to the inlet-side coolant chamber. [6] Stator arrangement according to one of the preceding claims, wherein the stator sleeve comprises a flange extending radially outwards and is configured to be coupled to a housing of an electric machine. [7] Stator arrangement according to claim 6, wherein the flange is positioned radially outside the outlet-side coolant chamber. [8] Stator arrangement according to one of the preceding claims, wherein the stator sleeve has one or more O-ring recesses profiled to accommodate O-rings configured to form a seal between the stator sleeve and a housing of an electric machine. [9] Stator arrangement according to one of the preceding claims, wherein the coolant deflector is coupled to a body of the stator sleeve via a deflector fastening device. [10] Stator arrangement according to any one of the preceding claims, further comprising: a multitude of axially extending tabs that interlock with a multitude of recesses in the stator core; a first axial damper arranged between the mounting device and the stator core; and / or a second axial damper arranged between an axial side of the stator core and an inner surface of the stator sleeve; and / or wherein the multitude of axially extending tabs each have a tab damper made of plastic or elastomer.

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