Electric motor cooling system

Abstract

A sealing assembly comprising:an elastomeric seal radially disposed between a side surface of a stator of an electric motor and a sealing ring, the elastomeric seal including a plurality of openings configured to receive a plurality of end windings of the stator and a molded annular bead disposed to define an inner diameter of the elastomeric seal and configured to be axially compressed to further separate a coolant for the plurality of end windings from a rotor.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to an electric motor having a cooling system including a sealed cavity formed around a stator end winding. BACKGROUND AND OVERVIEW

[0002] In electric vehicle motor applications, stator winding cooling is used to achieve higher motor efficiency. For example, certain applications may require oil to flow over the stator for efficiency reasons. However, certain earlier cooling system designs channel the oil through internal cavities, allowing oil to leak into an air gap between the rotor and stator. Oil in the air gap leads to drag losses, which significantly reduce motor efficiency. The inventors recognized that isolating the stator cooling system from other areas of the motor, such as the rotor compartment, can prevent an undesirable drop in motor efficiency.

[0003] One approach for an engine cooling system includes a sealing ring and a sealing boot. In the engine cooling system, a cavity is formed between the sealing ring and the sealing boot, within which an end winding of the stator is at least partially immersed in a coolant (e.g., oil). The interfaces between the sealing ring, sealing boot, stator, and rotor cavity may be sealed to reduce coolant flow from the channels into the rotor cavity. Some interfaces may be sealed, for example, by one or more gaskets, an O-ring, or an adhesive. However, sealing a potential leakage path to the air gap formed at the interface between an axial wall of the rotor cavity and the sealing ring-stator interface is particularly difficult due to the minimal area available for positioning a seal.Seal protrusions beyond the interface and into the rotor cavity can compromise the seal and increase the risk of oil leakage from the cooling channels into the rotor cavity. Self-adhesive sealants may not be desirable due to chemical incompatibility with the coolant.

[0004] To overcome at least some of the above-noted problems, the inventors have developed a sealing assembly for an electric motor cooling system. In one example, the sealing assembly includes an elastomeric seal radially disposed between a side surface of a stator of an electric motor and a sealing ring, the elastomeric seal including a plurality of openings configured to receive a plurality of end windings of the stator, and a molded annular bead disposed to define an inner diameter of the elastomeric seal and configured to be axially compressed to further separate a coolant for the plurality of end windings from a rotor. In this way, a sealed cavity is created that prevents fluid from flowing into the rotor cavity and, in particular, into the air gap of the motor.In this way, the engine can achieve a target efficiency if desired.

[0005] In another example, the formed annular bead, in the uncompressed state, may have a sealing surface with a concave profile in cross-section. The formed annular bead may include a first protrusion disposed on a first side of the elastomeric seal, a second protrusion disposed on a second side of the elastomeric seal, and a concave groove axially disposed between the first protrusion and the second protrusion. The first protrusion may increase toward the inner diameter of the elastomeric seal and extend inwardly, and the second protrusion may decrease toward the inner diameter of the elastomeric seal and extend inwardly. The concave groove may include a first edge, a second edge, and a groove surface extending axially therebetween.The concave groove may have a first edge approximately parallel to a first planar surface of the elastomeric seal and a second edge approximately parallel to a second planar surface of the elastomeric seal. In another example, the formed annular bead may extend radially inward to and no further than an axial wall of the seal ring upon final compression in an electric motor assembly. In this way, the geometry of the formed annular bead maintains the elastomeric seal at the minimum surface area and seals the rotor cavity from coolant without the elastomeric seal protruding into the rotor cavity.

[0006] It should be understood that the above summary is intended to introduce, in simplified form, a selection of concepts that are further explained in the detailed description. It is not intended to identify the most important or essential features of the claimed subject matter, the scope of which is clearly defined by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that address the disadvantages noted above or elsewhere in this disclosure. SHORT DESCRIPTION OF THE CHARACTERS Fig. 1 shows an electric motor with a cooling system. Fig. 2 shows a cross-sectional view of the Fig. 1 shown electric motor and cooling system. Fig. 3 shows an electric motor with a sealing ring, a sealing sleeve and an elastomer seal. Fig. 4 shows a bottom view of the Fig. 3 shown elastomer seal and sealing ring. Fig. Figure 5 shows an enlarged view of the underside of the elastomer seal and the sealing ring made of Fig. 4. Fig. 6A and Fig. 6B show different views of the Fig. 3 shown elastomer seal. Fig. 7 shows an enlarged view of the Fig. 3 shown electric motor. DETAILED DESCRIPTION

[0007] Systems and methods for a sealing assembly for an engine cooling system are described herein. The sealing assembly includes an elastomeric seal, a sealing ring, and a sealing boot held under pressure within a motor housing to form a sealed cavity around the end windings of the stator. The sealed cavities allow coolant (e.g., oil) to flow through the stator and a plurality of end windings of the stator while preventing the coolant from entering a rotor cavity. In particular, the elastomeric seal includes a molded annular bead compressed between a sealing interface of the stator and the sealing ring to create a seal. The seal created by the molded annular bead can at least fluid-tightly close the rotor cavity at the sealing interface and the sealing ring.The geometry of the molded annular bead profile is compressed so that it does not protrude into the electric motor's rotor cavity, allowing for consistent sealing pressure and contact width without overstressing the elastomer. The elastomer seal can exhibit high compliance and seal the rotor cavity over a range of temperature and pressure conditions. Consequently, the sealing ring and sealing boot can be securely held within the motor with the elastomer seal, reducing the likelihood of coolant leakage from the sealed cavity. This helps prevent drag losses caused by coolant in the air gap.

[0008] Fig. 1 shows a diagram of an electric motor 100. The electric motor 100 may be embodied as an electric motor-generator and integrated into a system 102, which may take various forms. For example, the electric motor 100 may be incorporated into an electric drive system of an electric vehicle (EV). Thus, the electric motor is a traction motor, and the electric drive may also include a transmission (e.g., a gear box). The EV example may, in one case, be a pure electric vehicle (e.g., a battery electric vehicle (BEV)) and, in another case, a hybrid electric vehicle (HEV) with an internal combustion engine. However, the motor may also be used in other suitable systems (e.g., stationary systems), such as industrial machinery, agricultural systems, mining systems, and the like.

[0009] The electric motor 100 includes a rotor 104 that electromagnetically interacts with a stator 106 to drive the rotation of a rotor shaft 108 contained within the rotor. The electric motor 100, in the illustrated example, includes a housing 110 having an electrical interface 112 for the stator 106. The electrical interface 112 may be a multi-phase electrical interface having multiple electrical terminals 114. The electrical interface 112 is a three-phase interface in the illustrated example. However, it should be understood that in other examples, the electrical interface may be a six- or nine-phase interface. More generally, the electric motor 100 may be a multi-phase alternating current (AC) machine. However, in other examples, the electric motor 100 may also be a direct current (DC) machine.

[0010] As in Fig. 1, the electric motor 100 may be electrically coupled to an inverter 116. The inverter 116 is designed to convert direct current (DC) to alternating current (AC) and vice versa. Thus, the electric motor 100 may be an AC electric motor, as stated above. However, in other examples, the electric motor 100 may be a DC motor (as stated previously), and the inverter 116 may therefore be omitted from the system 102. The inverter 116 may receive electrical energy from one or more energy storage devices 118 (e.g., traction batteries, capacitors, combinations thereof, and the like). The arrows 120 indicate the electrical energy transfer between the electric motor 100, the inverter 116, and the energy storage device(s) 118, which may occur during the various operating modes of the system.

[0011] System 102 may additionally include a control subsystem 180 having a controller 182. Controller 182 includes a processor 184 and memory 186. Memory 186 may store instructions that, when executed by processor 184, cause controller 182 to perform the various methods, control techniques, and the like described herein. Processor 184 may include a microprocessor unit and / or other types of circuitry. Memory 186 may include known data storage media, such as random access memory, read-only memory, keep-alive memory, combinations thereof, and the like.

[0012] The control unit 182 may receive various signals from sensors 188 located at various locations in the system 102. The sensors 188 may include a speed sensor for the electric machine, one or more temperature sensors for the energy storage device, one or more sensors for the state of charge of the energy storage device, a power sensor for the inverter, and the like. The control device 182 may also send control signals to various actuators 190 located at various locations in the system 102. For example, the control device may send signals to the inverter 116 to adjust the speed of the electric motor 100. In another example, the control device 182 may send a command signal to the electric motor 100 and / or the inverter 116, after which the motor speed may be adjusted.The other controllable components of system 102 may function in a similar manner with respect to the command signals and the adjustment of the actuators.

[0013] The system 102 may also include one or more input devices 192 (e.g., an accelerator pedal, a brake pedal, a console instrument panel, a touch interface, a touchpad, a keypad, combinations thereof, and the like). The input device(s) 192 may generate a request to adjust engine speed in response to user input.

[0014] For reference, an axis system is Fig. 1 and in Fig. 2-7. In one example, the z-axis may be a vertical axis (e.g., parallel to a gravitational axis), the x-axis may be a lateral axis (e.g., a horizontal axis), and / or the y-axis may be a longitudinal axis. However, in other examples, the axes may have other orientations. The rotational axis 199 of the electric motor 100 is shown in both Fig. 1 as well as in the Fig. 2-7. A section plane 2-2 for the Fig. The cross-sectional view shown in Figure 2 is in Fig. 1. The section plane 2-2 runs through the rotation axis of the electric motor 100.

[0015] Features described as axial may be approximately parallel to a datum axis unless otherwise noted. Features described as reverse may be approximately perpendicular to the datum axis unless otherwise noted. Features described as radial may circumferentially surround or extend outwardly from an axis, such as the datum axis, or a component or feature previously described as radial to a datum axis, unless otherwise noted. Unless otherwise noted, the axis referenced may be the axis of rotation 199.

[0016] Fig. Figure 2 shows a cross-sectional view of the electric motor 100 and the cooling system 200 for the motor. The rotor 104 and the stator 106 of the electric motor 100 are also shown, along with the housing 110, which at least partially encloses the rotor and the stator. The rotor shaft 108 is shown in Fig. 2 is shown in more detail.

[0017] The cooling system 200 may include a pump 202 and a filter 204 that can receive a coolant (e.g., oil such as natural and / or synthetic oil) and direct it into the stator 106. The pump 202 may create a pressure differential that allows the pump 202 to draw in and pressurize the coolant. The filter 204 may remove particles and other contaminants from the coolant. Arrows 205 show the coolant flow between the pump 202, the filter 204, and the cooling system 200. In one example, the pump 202 may feed coolant channels 206 that extend axially through a stator core 208 of the stator 106. However, other coolant flow patterns may be used in other examples. The pump 202 and the filter 204 are shown schematically. However, it should be understood that in practice, they may exhibit greater complexity. In addition, the pump and filter are shown at a certain distance from the electric motor 100.

[0018] An air gap 210 is formed between a rotor core 212 of the rotor 104 and the stator core 208. Sealing the coolant in the cooling system 200 as described here significantly reduces (e.g., prevents) the likelihood of coolant penetrating the air gap 210.

[0019] The cooling system 200 further includes a first sealing ring 214 and a first sealing collar 216 disposed on a first axial side 218 of the stator 106 (e.g., the stator core 208). The first axial side 218 may, for example, be a weld side. The first sealing ring 214 may be coupled to the stator 106 (e.g., the stator core). However, in other examples, the first sealing ring may be machined or otherwise integrated into the stator 106.

[0020] The first sealing collar 216 and the first sealing ring 214 are connected to each other via a first sealing interface 222 and a second sealing interface 224. The first sealing collar 216 and the stator 106 meet at a first lateral sealing interface 284. The first sealing interface 222, the second sealing interface 224, and the first lateral sealing interface 284 form a sealed cavity 226 in which the stator end winding 228 is located. The sealed cavity 226 can receive and / or discharge coolant to / from the coolant channels 206 in the stator core 208. For example, the sealed cavity 226 can at least partially immerse the stator end windings in coolant. The sealed cavity 226 is fluidly separated from a rotor cavity 227. In this way, the penetration of coolant into the air gap can be avoided, which increases the efficiency of the engine.

[0021] The first sealing interface 222 may be formed between the housing 110 and an extension 230 of the first sealing collar 216 located radially inward from the end coils 228. More specifically, the first sealing interface 222 may include a recess 231 profiled to receive a seal 233 such as an O-ring, gasket, diamond seal, and / or other type of fluid seal. The extension 230 of the first sealing collar 216 may taper inwardly in the axial direction to increase the strength of the collar compared to a thin-walled shoulder.

[0022] The first sealing ring 214 includes a flange 232 that extends axially outward from the first axial side 218 of the stator 106. The flange 232 seals against an inner surface 234 of the first sealing collar 216 to form the second sealing interface 224. In particular, the second sealing interface 224 may be a radial sealing interface. Therefore, the flange 232 and the inner surface 234 of the first sealing collar 216 enable a strong seal at the second sealing interface 224. However, it should be understood that other types of sealing interfaces may be used in other examples. The inner surface 234 of the first sealing collar 216 may include recesses sized to accommodate seals 236 such as O-rings, grommets, or a fluid seal.

[0023] The second sealing interface 224, in one example, may be located radially inward from the stator end winding 228 but radially outward from the first sealing interface 222. In this way, the sealed cavity 226 can be securely sealed to create a coolant enclosure for the end windings 228. The coolant 239 circulates around the cavity and specifically through the end windings 228, thereby improving stator cooling compared to systems that only direct coolant around the end windings 228.

[0024] The first lateral sealing interface 284 may be a radial seal formed between a side surface 282 of the stator 106 and the flange 232 of the first sealing ring 214. For example, the first lateral sealing interface 284 may be located axially inward of the first axial side 218 of the stator 106. In other words, the first lateral sealing interface 284 may be located to the right of the second sealing interface 224 along the y-axis. The first lateral sealing interface 284 may include a gasket, a diamond seal, a liquid seal, and / or an elastomeric seal 220 as defined in the present disclosure. The elastomeric seal 220 is illustrated schematically.

[0025] In one example, the elastomeric seal 220 may be disposed radially, with respect to the rotation axis 199, between the first seal ring 214 and the side surface 282 of the stator 106, adjacent the air gap 210. The elastomeric seal 220 may have openings configured to receive the end windings 228. The elastomeric seal 220 may extend radially from an inner peripheral portion 286 of the first seal ring 214 to an outer peripheral portion 280 of the first seal ring 214, with the inner peripheral portion 286 facing the rotor core 212 and the outer peripheral portion 280 facing the housing 110. The first lateral sealing interface 284 with the elastomer seal 220 further separates the coolant 239 from the air gap 210. In this way, the sealed cavity 226 is fluidly separated from the rotor cavity 227. Examples of the elastomer seal 220 are described with reference to Fig. 3-7 described in more detail.

[0026] In one example, the housing 110 may be formed from various sections that are connected to one another. For example, a crown-side section 240 and a weld-side section 242 may be connected to a housing body 244. The housing body 244 may circumferentially enclose the stator 106 and the sealing collars and rings in the cooling system 200. Fasteners 246 and / or other suitable fastening devices may be used to attach the crown-side section 240 and / or the weld-side section 242 to the housing body 244.

[0027] The first sealing collar 216 may include an inner radial wall 248, an outer radial wall 250, and an axial wall 252 that allow the sealed cavity 226 to enclose the end coils 228. However, in other examples, other contours of the first sealing collar 216 may be used. For example, the first sealing collar may include curved portions that enclose the end coils.

[0028] An end 251 of the outer radial wall 250 may abut or be in surface contact with a surface 253 of an outer peripheral portion 280. When the first sealing ring 214 is attached to the first sealing collar 216, the outer radial wall 250 of the first sealing collar 216 may abut or contact the outer peripheral portion 280 and overlap an outer flange (not shown). In this way, the upper portion of the sealed cavity 226 may be created.

[0029] The first sealing collar 216 in the second sealing interface 224 has a shoulder 254 with which the axial compression of the sealing assembly can be adjusted. More specifically, the shoulder 254 is firmly connected to the first sealing ring 214 when the sealing assembly is press-fitted into the housing 110. The arrows 256 indicate the compressive force exerted on the unit formed between the first sealing ring 214 and the first sealing collar 216. In this way, the first sealing ring and collar can be effectively held in a desired position. Due to this press-fit attachment of the sealing ring and collar in the housing, the use of fastening devices for attaching the ring and / or collar to the housing can be dispensed with, if desired.Consequently, manufacturing efficiency can be increased compared to systems that utilize fasteners. A second sealing ring 260 and a second sealing collar 262, described in more detail herein, can be compressed in a similar manner.

[0030] The coolant channels 206 may extend through the stator core 208 from the first axial side 218 to a second axial side 258. In this way, the coolant passes through the stator in an axial direction, allowing heat to be effectively dissipated. This allows the engine to achieve higher efficiency, if desired, compared to previous engine cooling systems.

[0031] A second sealing ring 260 and a second sealing collar 262 are disposed on the second axial side 258 (e.g., a crown side) of the stator 106 in the example shown. However, in other examples, the second sealing ring and collar may be omitted from the engine cooling system.

[0032] Similar to the first sealing ring 214 and the first sealing collar 216, the second sealing ring 260 and the second sealing collar 262 may form a third sealing interface 264 and a fourth sealing interface 266. The second sealing ring 260 and the stator 106 may form a second lateral sealing interface 288. Again, the third sealing interface 264 may be a face seal formed between the housing 110 and an extension 267. The fourth sealing interface 266 may be a radial seal formed between a flange 269 of the second sealing ring 260. The second lateral sealing interface 288 may be a radial seal formed between a side surface 290 of the stator 106 and the flange 269 of the second sealing ring 260.The second sealing ring 260 and the second sealing collar 262 may be dimensioned differently than the first sealing ring 214 and the first sealing collar 216 to accommodate the different sizes of the weld-side and crown-side end windings. However, the second sealing ring 260 and the second sealing collar 262 may have similar structural features to the first sealing ring 214 and the first sealing collar 216. However, as further discussed herein, the second sealing collar may be shaped to be mounted between the electrical interface 112 and the stator end winding 228.

[0033] In one example, an elastomeric seal 271 may be radially interposed between the side surface 290 of the stator core 208 and the second seal ring 260. Similar to the elastomeric seal 220, the elastomeric seal 271 may further separate the coolant for the end windings from the rotor core 212. However, in another example, the second seal ring may be secured to the stator with an adhesive. Seals 277 may be included in the fourth seal interface 266, and a seal 279 may be included in the third seal interface 264. The seal 279 may include one or more of an O-ring, a gasket, a diamond seal, and a fluid seal. Additionally, the seals 277 may include one or more O-rings, grommets, and / or fluid seals.

[0034] The second sealing sleeve 262 may include an inner radial wall 268, an outer radial wall 270, and an axial wall 272 that allow a sealed cavity 273 to enclose the end coils 228. However, in other examples, other contours of the second sealing sleeve 262 may be used.

[0035] The second sealing collar 262, in turn, has a shoulder 274 through which an axial compressive force is transmitted to adjust the axial compression of the sealing arrangement formed between the second sealing collar 262 and the second sealing ring 260 as desired. This axial compression is represented by arrows 275.

[0036] In Fig. 3 shows a sealing arrangement 300 of a cooling system of an electric motor, which is an embodiment of the cooling system 200 and the electric motor 100 of Fig. 1 or 2. The sealing arrangement 300 of the cooling system may include an elastomeric seal 306 disposed radially between a side surface 302a of a stator 302 and a sealing ring 304. The side surface 302a may be adjacent to or in contact with the sealing ring 304 and the elastomeric seal 306, with the elastomeric seal 306 being axially compressed against both the side surface 302a and the sealing ring 304. A sealing collar 308 may circumferentially surround the sealing ring 304 and form a sealed cavity 310 therebetween. The elastomeric seal 306 is in fluid communication with the sealed cavity 310. The elastomeric seal 306 may be an embodiment of the seals described above in Fig. 2 described elastomer seals 220, 271. A box 7-7 for the Fig. 7 shown detailed view is in Fig. 2. Box 7-7 illustrates a sealing interface formed between the sealing ring 304, the side surface 302a, and the elastomeric seal 306.

[0037] The sealing ring 304 may include an inner flange 312 and an outer flange 314. The sealing collar 308 may have an inner radial wall 316 and an outer radial wall 318. The outer radial wall 318 of the sealing collar 308 may be adjacent to or in contact with the outer flange 314 of the sealing ring 304. The inner radial wall 316 may be adjacent to or in contact with the inner flange 312. As described above with reference to Fig. 2, one or more of an O-ring, a gasket, a diamond seal, or a liquid seal may be disposed between the sealing ring 304 and the sealing sleeve 308 at one or more sealing interfaces formed therebetween, such as the sealing interface 320. In this way, the sealing ring 304 and the sealing sleeve 308 form the sealed cavity 310.

[0038] The inner flange 312 may have a first axial wall 322 and the stator 302 may have a second axial wall 324, wherein the first axial wall 322 and the second axial wall 324 both extend axially parallel to the rotation axis 199. A sealing interface 326 is formed between the first axial wall 322 and the second axial wall 324. In one example, the sealing interface 326 includes a sealing interface with minimal available area for contact and sealing with a gasket. In one example, the sealing area may be approximately 2 mm. The elastomeric seal 306 is configured to seal the sealing interface 326. In particular, the elastomeric seal 306 includes a molded annular bead 328 arranged to define an inner diameter of the elastomeric seal 306. The formed annular bead 328 is configured to be axially compressed, thereby sealing the sealing interface 326.In this manner, the elastomer seal 306 separates a coolant enclosed in the sealed cavity 310 and circulating through the cooling system from a rotor (e.g., the rotor core 212 in . Fig. 2).

[0039] Fig. 4 shows a bottom view 400 of the sealing ring 304 and the elastomer seal 306 of the sealing assembly 300 of an electric motor cooling system. The elastomer seal 306 is shown in an uncompressed state. The seal 306 described with reference to Fig. 3 are numbered similarly and are not listed again. A box 5-5 for the elements introduced in Fig. The enlarged view shown in Figure 5 is in Fig. 4 included.

[0040] In one example, the elastomeric seal 306 may have an inner circumference 412, an outer circumference 414, an outer diameter 416, and an inner diameter 418. The elastomeric seal 306 may be substantially annular (e.g., ring-shaped) and have a central opening 420. The elastomeric seal 306 may be radially symmetrical relative to a central axis coaxial with the rotation axis 199. The elastomeric seal 306 may be substantially planar (e.g., flat), including a planar portion 410 extending radially from the formed annular bead 328 to the outer diameter 416. The elastomeric seal 306 includes a plurality of openings, including a plurality of square openings 404 arranged radially outward from a plurality of rectangular openings 402. The plurality of openings may be arranged in the planar portion 410 and surround the central opening 420.In one example, each square opening of the plurality of square openings 404 may be radially aligned with a rectangular opening of the plurality of rectangular openings 402 with respect to the rotation axis 199. Specifically, each square opening of the plurality of square openings 404 and each rectangular opening of the plurality of rectangular openings 402 may be symmetrically divided by a common axis or line intersecting the rotation axis 199.

[0041] The sealing ring 304 may have an inner periphery 422 and an outer periphery 424 that are respectively aligned with the inner periphery 412 and the outer periphery 414 of the elastomeric seal 306. More specifically, the inner periphery 422 and the inner periphery 412 overlap, and the outer periphery 424 and the outer periphery 414 overlap when the sealing ring 304 contacts the elastomeric seal 306. The sealing ring 304 may include a plurality of channels, including a plurality of first channels 406 disposed radially outward from a plurality of second channels 408. The plurality of first channels 406 and the plurality of second channels 408 may be aligned with the plurality of rectangular openings 402 and the plurality of square openings 404, respectively. Specifically, the first channels 406 are disposed directly above the corresponding rectangular openings 402. Similarly, the plurality of second channels 408 overlie the square openings 404.The first channels 406 may be formed between baffles 426 extending in radial directions and connected to a stator (e.g., stator 106 in . Fig. 1-2) are aligned so that the coolant flows through the first channels 406 and is directed to the end windings. The first channels 406 may, in one example, have a rectangular cross-section. However, other channel profiles have also been considered.

[0042] The plurality of rectangular openings 402 are shaped to receive the plurality of end windings of a stator (e.g., the end windings 228 of the stator 106 in Fig. 2). The plurality of square openings 404 are configured to communicate with the plurality of rectangular openings 402 and the cooling system (e.g., the cooling system 200 in Fig. 2) to be in fluid communication. For example, the elastomer seal 306 may be disposed over the end windings on the side surface 302a of the stator 302 (see, e.g., Fig. 3). The end windings can be guided through the plurality of rectangular openings 402, through the plurality of first channels 406 into the sealed cavity (e.g., sealed cavity 310 in Fig. 3). The coolant can enter the sealed cavity through the plurality of rectangular openings 402 via the first channels 406, where the coolant can exchange heat with the stator windings, and exit the sealed cavity through the plurality of second channels 408 aligned with the square openings 404.

[0043] In one example, the elastomer seal 306 may be relatively more flexible, compressible, and compliant than the seal ring 304, the seal collar 308, or the stator 302 (see Fig. 3). In one example, the elastomeric seal 306 may be formed from molded rubber, and the plurality of rectangular openings 402 and the plurality of square openings 404 may be stamped. Additionally or alternatively, the elastomeric seal 306 may be formed from acrylic, foam rubber, ceramic paper, or polyurethane. The seal ring 304 and the seal boot 308 may be formed from relatively rigid materials such as metal, ceramic, or composite materials of metal or ceramic. In this way, at least some portions of the geometry of the elastomeric seal 306 may change when it is axially compressed between the seal ring 304, the stator 302, and the seal boot 308. The geometry of the elastomeric seal and how at least some portion of the geometry may change under various pressure and thermal conditions is described in more detail below.

[0044] Fig. 5 shows an enlarged view 500 of the bottom view 400 of the sealing ring 304 and the elastomer seal 306 shown in Fig. 4. The figures shown with reference to the Fig. The elements introduced in sections 3-4 are numbered similarly and are not listed again.

[0045] The enlarged view 500 shows that the plurality of rectangular openings 402 and the plurality of square openings 404 are arranged radially in the planar portion 410 of the elastomeric seal 306. The plurality of rectangular openings 402 and the plurality of square openings 404 may be arranged radially to the rotation axis 199. In one example, each rectangular opening of the plurality of rectangular openings 402 may be defined by an opening on a first surface 510 of the elastomeric seal 306, an opening on an opposite second surface 610 (see, e.g., Fig. 6A-6B) and a rectangular surface 508. Each rectangular opening of the plurality of rectangular openings 402 may include a pair of long sides 506 and a pair of short sides 504 arranged perpendicular to the pair of long sides 506. The plurality of rectangular openings 402 may include a first short side 504a and a second short side 504b. The first short side 504a of each of the plurality of rectangular openings 402 may abut the formed annular ridge 328. The second short side 504b may face one of the plurality of square openings 404. Each square opening of the plurality of square openings 404 may be defined by an opening on the first surface 510 of the elastomeric seal 306, an opening on the second surface 610, and a square surface 514. Each square opening of the plurality of square openings 404 may have four vertically arranged sides 512.The plurality of square openings 404 and sides 512 may include a first side 512a facing the outer perimeter 414 and a second side 512b facing one of the plurality of rectangular openings 402.

[0046] The enlarged view 500 shows the plurality of first channels 406 and the plurality of second channels 408. Each first channel of the plurality of first channels 406 may be defined by an opening on a first surface 526 of the seal ring 304, an opening on an opposite second surface 528, and a first channel surface 520. Each first channel of the plurality of first channels 406 includes a pair of first long channel sides 518 and a pair of first short channel sides 516 arranged perpendicular to the pair of first long channel sides 518. Each second channel of the plurality of second channels 408 may be defined by an opening on the first surface 526 of the seal ring 304, an opening on the second surface 528, and a second channel surface 524. Each second channel of the plurality of second channels 408 includes four perpendicularly arranged second channel sides 522.The plurality of first channels 406 and the plurality of second channels 408 are similarly shaped and aligned with the plurality of rectangular openings 402 and the plurality of square openings 404, respectively. In this manner, the seal ring 304 and the elastomeric seal 306 direct coolant flow from the plurality of coolant channels in the stator to the plurality of end windings in the sealed cavity (e.g., from the coolant channels 206 to the end windings 228 in the sealed cavity 226 in . Fig. 2).

[0047] Fig. 6A and Fig. 6B show a cross-sectional view 600 of the elastomer seal 306 of the seal assembly 300 of an electric motor cooling system. The elastomer seal 306 is shown in an uncompressed state. The Fig. The elements introduced in Figures 3-5 are numbered similarly and are not listed again. A box 6-6 for an enlarged cross-sectional view of Figure 650 from Fig. 6B is in Fig. 6A.

[0048] The cross-sectional view 600 in Fig. 6A first shows the formed annular bead 328 defining the inner diameter 418 of the elastomeric seal 306 and the planar portion 410 extending radially from the formed annular bead 328 to the outer diameter 416. The elastomeric seal 306 may have a radial length 616 extending from the inner diameter 418 to the outer diameter 416. In one example, the radial length may have a threshold range (e.g., a range of thresholds) of 31.5 mm to 37.5 mm. The elastomeric seal 306 further includes a wall 602. In one example, the formed annular bead 328, in its uncompressed state, as shown in cross-sectional view 600 and Box 6-6, has a radial enlargement 603 with a concave profile in cross-section. For example, the wall 602 at the radial thickening 603 may be relatively thicker than the wall 602 extending through the planar portion 410.For example, the wall 602 may have a first axial length 612 extending radially through the planar portion 410 and a second axial length 614 extending through the maximum dimension of the radial thickening 603 (e.g., along the y-axis). In one example, the second axial length 614 may include a threshold relative thickness that is 1.7 to 1.5 times the first axial length 612. In one example, the second axial length 614 may have a threshold of 1.6 mm to 2.3 mm. In one example, the first axial length may have a threshold of 0.8 cm to 1.45 mm.

[0049] To Fig. 6B: In one example, the formed annular bead 328 may include a first protrusion 606 disposed on the first surface 510 of the elastomeric seal 306, a second protrusion 608 disposed on a second surface 610 of the elastomeric seal 306, and a concave groove 604 axially disposed between the first protrusion 606 and the second protrusion 608. The first protrusion 606 may have a first side 618 and a second side 620. The first protrusion 606 decreases downwardly (e.g., relative to the y-axis) along the first side 618 and inwardly toward the inner diameter 418. The first protrusion 606 increases toward the inner diameter 418 along the second side 620. The second protrusion 608 may have a third side 622 and a fourth side 624. The second projection 608 increases along the third side 622 upwardly and inwardly toward the inner diameter 418.The second protrusion 608 tapers downwardly and inwardly along the fourth side 624 toward the inner diameter 418. The concave groove 604 may further include a first edge 630, a second edge 632, and a groove surface 634 extending axially therebetween. In one example, the first edge 630 may be approximately parallel to the first surface 510 of the elastomeric seal 306, and the second edge 632 may be approximately parallel to the second surface 610. In one example, the elastomeric seal may be bilaterally symmetrical along an axis 628 of bilateral symmetry. The axis 628 of bilateral symmetry may be parallel to the Z-axis (e.g., the vertical axis).

[0050] Fig. 7 shows an enlarged view 700 of the sealing assembly 300 of an electric motor cooling system with the elastomer seal 306 disposed radially between the side surface 302a of the stator 302 and the sealing ring 304. The enlarged view 700 shows the sealing interface 326 formed between the first axial wall 322 of the sealing ring 304, the second axial wall 324 of the stator 302, and the elastomer seal 306. The seal assembly 300 described with reference to FIG. Fig. The elements introduced in chapters 3-7 are numbered similarly and are not listed again.

[0051] When the seal assembly 300 is installed in the housing 110 of an electric motor assembly, a compressive force is exerted on the assembly upon final compression. Arrows 702 indicate the compressive force exerted on the assembly formed between the seal ring 304 and the stator 302, as well as the elastomeric seal 306 disposed therebetween. Upon axial compression, the elastomeric seal 306 can be compressed by the seal collar 308 and the inner flange 312 in a first direction 702a. Likewise, upon axial compression, the elastomeric seal 306 can be compressed by the stator 302 in a second direction 702b. The first direction 702a and the second direction 702b are opposite to each other.

[0052] The formed annular bead 328 may be formed from a relatively thermoplastic material. For example, under relatively low pressure and / or heat conditions (e.g., at ambient temperature), the formed annular bead 328 may have an axial dimension corresponding to the second axial length 614. However, under relatively higher pressure and / or heat conditions, such as during final compression in the electric motor and during engine operation, the size of the formed annular bead 328 may change. For example, at final compression, the formed annular bead 328 may compress axially to approximately the first axial length 612. Additionally, the axial compression of the formed annular bead 328 may cause extrusion (or expansion) along the z-axis, thereby filling the sealing interface 326. For example, the formed annular bead 328 may be compressed to a vertical length (e.g.,along the z-axis) of approximately 2 mm. In this way, the formed annular bead 328 can rest on the minimal sealing surface of the sealing interface 326 and form a seal.

[0053] Due to the concave profile of the formed annular ridge 328, the formed annular ridge 328 extends radially inward to the first axial wall 322 of the seal ring 304, as indicated by arrow 704, and no further than the second axial wall 324, which is approximately parallel to the first axial wall 322. By extending to and no beyond the first axial wall 322 of the seal ring 304 and the second axial wall 324 of the stator 302, the elastomeric seal 306 seals the coolant within the sealed cavity 310 without protruding into the rotor core. Additionally, due to the relative plasticity of the elastomer seal 306, the elastomer seal 306 can conform to the seal interface 326 as pressure and thermal conditions change during engine operation, which can result in expansion and contraction of the seal interface 326.The formed annular bead 328 can compress to the dimension of the seal interface 326 under the heat and pressure conditions of the operating engine without squeezing into the rotor core.

[0054] In this way, the disclosed sealing assembly for a cooling system of an electric motor can fluidly isolate the coolant for the end windings of the stator from an air gap formed between a stator and a rotor core. The sealing assembly includes an elastomeric seal configured to allow end windings of the stator to enter a sealed cavity of the cooling system. The elastomeric seal further includes a molded annular bead defining an inner diameter of the elastomeric seal and axially compressed with respect to a longitudinal axis and / or a rotational axis of the rotor to seal an interface formed at the air gap. The molded annular bead may have a radial thickening with a concave profile in cross-section.During final compression in an electric motor assembly, the geometry of the molded annular bead maintains the elastomer seal at the minimum surface area, fluidly sealing the rotor without protruding beyond the interface. The technical effect of the sealing arrangement is that the stator end windings are effectively cooled by a sealed cavity, reducing (e.g., eliminating) the risk of coolant leaking into the rotor cavity, thereby increasing motor efficiency compared to previous motor cooling systems.

[0055] The disclosure also provides support for a sealing assembly comprising: an elastomeric seal radially disposed between a side surface of a stator of an electric motor and a seal ring, the elastomeric seal including a plurality of openings configured to receive a plurality of end windings of the stator, and a molded annular bead disposed to define an inner diameter of the elastomeric seal and configured to be axially compressed to further separate a coolant for the plurality of end windings from a rotor. In a first example of the system, the molded annular bead, in its uncompressed state, has a radial bulge having a concave profile in cross-section.In a second example of the system, optionally including the first example, the formed annular bead, in an uncompressed state, comprises a first protrusion disposed on a first side of the elastomeric seal, a second protrusion disposed on a second side of the elastomeric seal, and a concave groove axially disposed between the first protrusion and the second protrusion. In a third example of the system, optionally including one or both of the first and second examples, the first protrusion tapers downwardly and inwardly from the first surface of the elastomeric seal toward the inner diameter, and the second protrusion tapers upwardly and inwardly from the second surface of the elastomeric seal toward the inner diameter.In a fourth example of the system, optionally comprising one or more or each of the first to third examples, the concave groove comprises a first edge, a second edge, and a groove surface extending axially therebetween, the first edge being approximately parallel to the first surface of the elastomeric seal and the second edge being approximately parallel to the second surface of the elastomeric seal. In a fifth example of the system, optionally comprising one or more or each of the first to fourth examples, the formed annular bead, upon final compression in an electric motor assembly, extends to and no further than an axial wall of the seal ring in a radially inward direction.In a sixth example of the system, optionally comprising one or more or each of the first to fifth examples, the elastomeric seal comprises a planar portion extending radially from the formed annular bead to an outer diameter. In a seventh example of the system, optionally comprising one or more or each of the first to sixth examples, the plurality of openings comprises a plurality of square openings disposed radially outwardly of a plurality of rectangular openings, the plurality of rectangular openings configured to receive the plurality of end windings of the stator, and the plurality of square openings configured to be in fluid communication with the plurality of rectangular openings.In an eighth example of the system, optionally including one or more or each of the first to seventh examples, the elastomeric seal is made of molded rubber, and the plurality of rectangular openings and the plurality of square openings are stamped. In a ninth example of the system, optionally including one or more or each of the first to eighth examples, each square opening of the plurality of square openings is radially aligned with a rectangular opening of the plurality of rectangular openings with respect to a central axis of the elastomeric seal.

[0056] The disclosure also supports a cooling system for an electric motor, comprising: a stator having a plurality of end windings and a plurality of coolant channels extending axially through the stator, the plurality of coolant channels being in fluid communication with the plurality of end windings, a sealing ring coupled to the stator and having a plurality of channels receiving the plurality of end windings, a sealing boot in contact with the sealing ring and forming a sealed cavity between the sealing boot and the sealing ring, the sealed cavity being configured to at least partially immerse the plurality of end windings in a coolant, and an elastomeric seal radially disposed between a side surface of the stator and the sealing ring, the elastomeric seal having a plurality of openings configured to receive the plurality of end windings,and a molded annular bead arranged to define an inner diameter of the elastomeric seal and configured to be axially compressed to further separate the coolant for the plurality of end windings from a rotor. In a first example of the system, the elastomeric seal extends radially from an inner peripheral portion of the seal ring to an outer peripheral portion of the seal ring, with the inner peripheral portion facing a rotor core and the outer peripheral portion facing a motor housing. In a second example of the system, optionally including the first example, the plurality of channels directs a coolant flow from the plurality of coolant channels in the stator to the plurality of end windings. In a third example of the system, optionally including one or both of the first and second examples,The molded annular bead, in an uncompressed state, comprises a sealing interface with a concave profile in cross-section, and wherein, upon final compression in an electric motor assembly, the molded annular bead extends to an axial wall of the seal ring and no further than this in a radially inward direction. In a fourth example of the system, optionally comprising one or more or each of the first to third examples, the elastomeric seal comprises a plurality of square openings disposed radially outwardly of a plurality of rectangular openings, the plurality of square openings being in fluid communication with the plurality of coolant channels in the stator.

[0057] The disclosure also supports a method for a cooling system, comprising: directing coolant from a plurality of coolant channels extending through a stator into a sealed cavity formed between an elastomeric seal, a seal ring, and a seal boot and enclosing end windings of the stator, wherein the elastomeric seal includes a shaped annular bead disposed to define an inner diameter of the elastomeric seal and configured to be axially compressed to further separate the coolant from an air gap formed at an interface between the stator and a rotor. In a first example of the method, the sealed cavity is fluidly isolated from a rotor cavity.In a second example of the method, optionally including the first example, the formed annular bead, in an uncompressed state, comprises a sealing interface with a concave profile in cross-section, and wherein, upon final compression in an electric motor assembly, the formed annular bead extends to and no further than an axial wall of the seal ring in a radially inward direction. In a third example of the method, optionally including one or both of the first and second examples, the elastomeric seal comprises a planar portion extending radially from the formed annular bead to an outer diameter.In a fourth example of the method, optionally comprising one or more or each of the first to third examples, the planar portion comprises a plurality of rectangular openings and a plurality of square openings disposed radially outwardly of the plurality of rectangular openings, the plurality of rectangular openings abutting the formed annular ridge, the plurality of rectangular openings receiving the end windings of the stator, and the plurality of square openings allowing coolant flow to the plurality of coolant channels.

[0058] In another embodiment, an electric motor comprises: a rotor, a stator circumferentially surrounding the rotor, an air gap disposed between the rotor and the stator, and an elastomeric seal radially disposed between a side surface of the stator and a seal ring, the elastomeric seal including a plurality of openings configured to receive a plurality of end windings of the stator, and a molded annular bead disposed to define an inner diameter of the elastomeric seal and configured to be axially compressed to further separate a coolant for the plurality of end windings from entering the air gap.

[0059] Fig. 1-7 are drawn approximately to scale, except for the schematically illustrated components. However, in other embodiments, the components may have different relative dimensions.

[0060] Fig.1-7 show example configurations with the relative arrangement of the various components. When these elements are in direct contact with each other or are directly coupled, they may be referred to as being in direct contact or directly coupled, respectively, at least in one example. Similarly, elements shown side by side or adjacent to each other may be adjacent to each other or adjacent to each other, at least in one example. For example, components that are in surface-to-surface contact with each other may be referred to as being in surface-to-surface contact. As another example, in at least one instance, elements that are separated from each other with only a space between them and that do not have any other components may be referred to as such.In yet another example, elements depicted above / below, on opposite sides, or to the left / right of each other may be referred to as such, relative to each other. Further, in at least one example, as depicted in the figures, a topmost element or point of an element may be referred to as a "top" of the component, and a bottommost element or point of the element may be referred to as a "bottom" of the component. As used herein, the terms top / bottom, upper / lower, above / below may refer to a vertical axis of the figures and may be used to describe the positioning of elements of the figures relative to each other. Thus, in one example, elements displayed above other elements are arranged vertically above the other elements.As another example, the shapes of the elements depicted in the figures may be referred to as such (e.g., circular, straight, flat, curved, rounded, beveled, angled, and the like). Furthermore, in one example, elements that are coaxial with one another may be referred to as such. Further, in at least one example, the depicted elements that intersect one another may be referred to as intersecting elements or as intersecting elements. Furthermore, an element depicted inside or outside another element may be referred to as such. In other examples, elements that are offset from one another may be referred to as such. Elements that are coaxial or parallel to one another may also be referred to as such. Another example: features described as being "substantially" shaped, e.g.,annular, flat, planar, prismatic, circular, etc., mean that the features are sufficiently shaped as such to be regarded as such by a person skilled in the art.

[0061] It should be noted that the example control and estimation routines contained herein can be used with various engine configurations. The control methods and routines disclosed herein can be stored as executable instructions in non-transitory 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 vehicle hardware in combination with the electronic control device. Thus, the described actions, operations, and / or functions can graphically represent code programmed into non-transitory memory of the computer-readable storage medium in the vehicle and / or the powertrain control system. One or more of the illustrated actions, operations, and / or functions can be performed repeatedly depending on the particular method used.One or more of the process steps described here can be omitted if desired.

[0062] Although various embodiments have been described above, they are to be considered as examples and not as limitations. It will be apparent to those skilled in the art that the disclosed subject matter may be embodied in other specific forms without departing from the spirit of the subject matter. The embodiments described above are, therefore, to be considered in all respects as illustrative and not restrictive. Thus, the configurations and routines disclosed herein are exemplary in nature, and the specific examples are not to be considered limiting, since numerous variations are possible. The subject matter of the present 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 characteristics disclosed herein.

[0063] The following claims particularly point out certain combinations and subcombinations that are considered novel and non-obvious. These claims may refer to "a" element or "a first" element, or the equivalent thereof. Such claims are to be construed as including the inclusion of one or more such elements, neither requiring nor excluding two or more such elements. 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 broader, narrower, equal, or different in scope than the original claims, are also to be considered included within the subject matter of the present disclosure.

Claims

[1] Sealing arrangement comprising: an elastomeric seal radially disposed between a side surface of a stator of an electric motor and a seal ring, the elastomeric seal including a plurality of openings configured to receive a plurality of end windings of the stator and a molded annular bead disposed to define an inner diameter of the elastomeric seal and configured to be axially compressed to further separate a coolant for the plurality of end windings from a rotor. [2] Sealing arrangement according to claim 1, wherein the formed annular bead in the uncompressed state has a radial thickening with a concave profile in cross-section. [3] A sealing arrangement according to any one of the preceding claims, wherein the formed annular bead in an uncompressed state comprises a first projection disposed on a first surface of the elastomeric seal, a second projection disposed on a second surface of the elastomeric seal, and a concave groove disposed axially between the first projection and the second projection. [4] The sealing assembly of claim 3, wherein the first projection decreases downwardly and inwardly from the first surface of the elastomeric seal toward the inner diameter and the second projection increases upwardly and inwardly from the second surface of the elastomeric seal toward the inner diameter. [5] A sealing arrangement according to claim 3 or 4, wherein the concave groove has a first edge, a second edge and a groove surface extending axially therebetween, the first edge being approximately parallel to the first surface of the elastomeric seal and the second edge being approximately parallel to the second surface of the elastomeric seal. [6] A sealing arrangement according to any one of the preceding claims, wherein the formed annular bead extends up to an axial wall of the sealing ring and no further than this in a radial direction inwardly upon final compression in an electric motor arrangement. [7] A sealing arrangement according to any one of the preceding claims, wherein the elastomeric seal comprises a planar portion extending radially from the formed annular bead to an outer diameter. [8] A sealing arrangement according to any one of the preceding claims, wherein the plurality of openings comprises a plurality of square openings arranged radially outwardly of a plurality of rectangular openings, the plurality of rectangular openings being arranged to receive the plurality of end windings of the stator, and the plurality of square openings being arranged to be in fluid communication with the plurality of rectangular openings. [9] The sealing assembly of claim 8, wherein the elastomeric seal is formed of molded rubber and the plurality of rectangular openings and the plurality of square openings are stamped. [10] A sealing assembly according to claim 8 or 9, wherein each square opening of the plurality of square openings is radially aligned with a rectangular opening of the plurality of rectangular openings with respect to a central axis of the elastomeric seal. [11] Cooling system for an electric motor, comprising: a stator comprising a plurality of end windings and a plurality of coolant channels extending axially through the stator, the plurality of coolant channels being in fluid communication with the plurality of end windings; a sealing ring coupled to the stator and having a plurality of channels that receive the plurality of end windings; a sealing sleeve in contact with the sealing ring and forming a sealed cavity between the sealing sleeve and the sealing ring, the sealed cavity being configured to at least partially immerse the plurality of end windings in a coolant; and an elastomeric seal radially disposed between a side surface of the stator and the seal ring, the elastomeric seal including a plurality of openings configured to receive the plurality of end windings, and a molded annular bead configured to define an inner diameter of the elastomeric seal and configured to be axially compressed to further separate the coolant for the plurality of end windings from a rotor. [12] The cooling system of claim 11, wherein the elastomeric seal extends radially from an inner peripheral portion of the seal ring to an outer peripheral portion of the seal ring, the inner peripheral portion facing a rotor core and the outer peripheral portion facing a motor housing. [13] The cooling system of claim 11 or 12, wherein the plurality of channels directs a flow of coolant from the plurality of coolant channels in the stator to the plurality of end windings. [14] A cooling system according to any one of claims 11 to 13, wherein the formed annular bead in an uncompressed state has a sealing surface with a concave profile in cross-section and wherein the formed annular bead extends up to and no further than an axial wall of the sealing ring in a radial direction in a final compression in an electric motor assembly. [15] The cooling system of any one of claims 11 to 14, wherein the elastomeric seal comprises a plurality of square openings disposed radially outwardly of a plurality of rectangular openings, the plurality of square openings being in fluid communication with the plurality of coolant channels in the stator.

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