Electric motor with winding cooling liners

Abstract

An example electric motor includes: a stator having a plurality of poles such that a slot is formed between each pair of adjacent poles of the plurality of poles; a plurality of wire windings respectively wrapped around the plurality of poles, wherein coolant flows through the slot to cool adjacent wire windings; a rotor, wherein an airgap is formed between the stator and the rotor; and a cooling liner disposed in the slot, wherein the cooling liner is coupled to the adjacent poles to prevent coolant flowing in the slot from entering the airgap, wherein the cooling liner has one or more thermal boundary layer disrupting features.

Description

Electric Motor with Winding Cooling LinersCROSS REFERENCE TO RELATED APPLICATION

[0001] The present application claims priority to U.S. Provisional Patent Application No. 63 / 714,594, filed on October 31, 2024, the entire contents of which are herein incorporated by reference as if fully set forth in this description.BACKGROUND

[0002] An electric motor is an electrical machine that converts electrical energy into mechanical energy. An example electric motor can include a stator and a rotor mounted within the stator. The stator can have plurality of wire windings.

[0003] Most electric motors operate through the interaction between the motor’s magnetic field and electric current in the wire windings of the stator to generate force in the form of rotation of a shaft. Electric motors can be powered by direct current (DC) sources, such as from batteries, motor vehicles or rectifiers, or by alternating current (AC) sources, such as a power grid, inverters, or electrical generators.

[0004] The torque and power generated at the shaft of the motor are limited by how much current or electric power is input through the wire windings. Increasing current beyond a certain limit can increase the temperature of the wire windings and cause damage to the wires and the electric motor. Thus, output power may be limited by the ability to transfer heat away from the motor.

[0005] In conventional cooling configurations, cooling oil may be sprayed on the end turns of the wire windings or the motor is completely submerged in cooling oil, including the airgap between the stator and the rotor of the motor. However, both of these configurations may lead to lossesand reduction of motor efficiency. For example, submersion of the rotor in oil may lead to high windage losses.

[0006] It may thus be desirable to have a motor configuration that enables transfer of heat from the wire windings while keeping the airgap free of oil. It is with respect to these and other considerations that the disclosure made herein is presented.SUMMARY

[0007] The present disclosure describes implementations that relate to an electric motor with winding cooling liners.

[0008] In a first example implementation, the present disclosure describes an electric motor. The electric motor includes: a stator having a plurality of poles such that a slot is formed between each pair of adjacent poles of the plurality of poles; a plurality of wire windings respectively wrapped around the plurality of poles, wherein coolant flows through the slot to cool adjacent wire windings; a rotor, wherein an airgap is formed between the stator and the rotor; and a cooling liner disposed in the slot, wherein the cooling liner is coupled to the adjacent poles to prevent coolant flowing in the slot from entering the airgap, wherein the cooling liner has one or more thermal boundary layer disrupting features.

[0009] In a second example implementation, the present disclosure describes a method of operating the electric of the first example implementation.

[0010] In a third example implementation, the present disclosure describes a method of making, forming, or assembling the electric motor of the first example implementation.

[0011] The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, implementations, and features described above, further aspects, implementations, and features will become apparent by reference to the figures and the following detailed description.BRIEF DESCRIPTION OF THE FIGURES

[0012] Figure 1A illustrates a perspective view of an electric motor, according to an example implementation.

[0013] Figure IB illustrates a front view of the electric motor of Figure 1A, according to an example implementation.

[0014] Figure 2A illustrates a perspective view of a stator of the electric motor of Figures 1A-1B, according to an example implementation.

[0015] Figure 2B illustrates a perspective view of the stator of Figure 2A from a different angle, according to an example implementation.

[0016] Figure 3 illustrates a partial front view of the stator of Figures 2A-2B, according to an example implementation.

[0017] Figure 4 illustrates a partial front view of the stator of Figure 3 with cooling liners disposed in slots between poles of the stator, according to an example implementation.

[0018] Figure 5 illustrates illustrates a perspective view of a cooling liner, according to an example implementation.

[0019] Figure 6 illustrates a perspective view of a cooling liner, according to an example implementation.

[0020] Figure 7 illustrates a perspective view of a cooling liner, according to an example implementation.

[0021] Figure 8 illustrates a perspective view of a cooling liner, according to an example implementation.

[0022] Figure 9 is a flowchart of a method of assembling and / or operating an electric motor, according to an example implementation.DETAILED DESCRIPTION

[0023] Within examples, disclosed herein is an electric motor (e.g., a needle wound servo motor) with liquid cooling liner integrated or inserted into slots between the teeth or poles of a stator of the electric motor. The cooling liners are configured as a cooling fluid turbulator to improve heat transfer through mixing and disruption of a thermal boundary layer of the cooling fluid. The terms “cooling fluid” and “coolant” are used exchangeably herein.

[0024] In the disclosed implementations, the entire side of the wire winding or coil is in contact with cooling fluid as opposed to just the end turns of the wire windings. Further, cooling fluid does not flow or penetrate the airgap, thereby reducing windage losses and increasing efficiency compared to configurations that involve submersion of the rotor and flooding the airgap with liquid.

[0025] Figure 1A illustrates a perspective view of an electric motor 100, and Figure IB illustrates a front view of the electric motor 100, according to an example implementation. In the example implementation of Figures 1A-1B, the electric motor 100 is configured as a frameless motor that might not have a motor frame or housing. Rather, the electric motor 100 has a stator 102 and a rotor 104 that may directly be mounted onto a structure of a machine (e.g., a vehicle). However, the cooling features described herein can be used with motors having housings as well.

[0026] In the example implementation of Figures 1A-1B, the rotor 104 has magnet slots, such as magnet slot 106, in which permanent magnets may be disposed. However, in other implementations, the magnets may rather be attached to an exterior surface of the rotor 104, between the rotor 104 and the stator 102, and in some implementations, such as synchronous reluctance and induction motor configurations, no magnets are used. An airgap 107 separates the stator 102 from the rotor 104, as shown in Figure IB.

[0027] As described below, the stator 102 has wire windings that receive electric current therethrough in a particular sequence, thereby generating a rotating magnetic field that interacts with the rotor to cause the rotor 104 to rotate. The electric motor 100 has a shaft 108 that is coupled to the rotor 104, such that rotary motion of the rotor 104 is transmitted to the shaft 108, which in turn drives an element of a machine (e g., a wheel, a gear, etc.).

[0028] In an example, the stator 102 has a lamination stack 109 that is generally cylindrical in shape as shown. The stator 102 can also have a first or proximal stator ring 110 and a second or distal stator ring 112. The stator rings 110, 112 may be separate components that are mounted or coupled to the lamination stack 109, or in other examples, the stator rings 110, 112 may be integrated with the lamination stack 109.

[0029] The proximal stator ring 110 has a first phase lead port 114, a second phase lead port 116, and a third phase lead port 118. In an example, three-phase AC power is provided from an inverter (e.g., power modules) via wires routed respectively through the phase lead ports 114-118 to the wire windings of the stator 102. In some implementations, a single phase lead port can be used instead of multiple ports, and such single port may accommodate all the phase leads or wires therethrough.

[0030] The proximal stator ring 110 may further have a sensor wire port 120. A low voltage signal wire, e.g., from a temperature sensor of the electric motor 100, can be routed through the sensor wire port 120 to a controller of the electric motor 100, for example.

[0031] Further, the proximal distal ring 110 has a coolant inlet port 122. A coolant is provided through the coolant inlet port 122 to flow within the electric motor 100 and absorb heat from the wire windings of the stator 102.

[0032] Figure 2A illustrates a perspective view of the stator 102, and Figure 2B illustrates a perspective view of the stator 102 from a different angle, according to an example implementation. As shown in Figure 2B, the distal stator ring 112 has a coolant outlet port 124. A coolant pump (now shown) may be configured to provide fluid through the coolant inlet port 122, and coolant then flows through the stator 102, as described in more detail below, to absorb heat from the wire windings of the stator 102. Coolant is then discharged from the coolant outlet port 124.

[0033] In examples, the coolant may then be cooled via a heat exchanger before being returned back to the coolant pump to complete the coolant circuit.

[0034] Figure 3 illustrates a partial front view of the stator 102, according to an example implementation. The lamination stack 109 forms of is configured as a stator body 126 that is generally cylindrical in shape as shown.

[0035] The stator body 126 has a yoke 127. The stator body 126 also has a plurality of teeth or poles such as pole 128, pole 130, pole 132, and pole 134, protruding or projecting radially inward toward the rotor 104 from the yoke 127. The poles are arranged in a circular array about the interior surface of the stator body 126. The rotor 104 is now shown in Figure 3 to reduce visual clutter in the drawing, but it should be understood that the rotor 104 is disposed in the interior space formed within the stator 102. Although the example implementations of the figures show the poles projecting inward as the rotor is disposed inside the stator, it is contemplated that in some implementations the rotor may be disposed outside the stator, and the poles may thus protrude radially outward from the stator body.

[0036] With this configuration, slots, such as slot 136, slot 138, and slot 140, are formed between each pair of adjacent poles. Particularly, a slot is formed and is circumferentially interposed between each two adjacent poles of the stator 102.

[0037] Coils or wire windings of the stator 102 may then be wrapped around at least some of the poles of the stator 102 such that the wire windings traverse or are disposed in the slots of the stator 102. For example, the electric motor 100 can be a needle-would type of motor where a needle fits through the slots, and is used to wrap the wires around the respective poles.

[0038] As depicted in Figure 3, a coil or wire winding 142 is wrapped around the pole 128, a wire winding 144 is wrapped around the pole 130, a wire winding 146 is wrapped around the pole 132, and a wire winding 148 is wrapped around the pole 134. In examples, the poles may have respective end-turn insulators (e.g., dielectric components) disposed at the respective axial ends of the pole to electrically insulate the end turns of the wire windings from the poles (e.g., from the lamination stack 109 or the stator body 126).

[0039] Such end-turn insulators may have bobbin flanges at their respective radially-inward ends (or radially-outward ends in some implementations having the rotor outside the stator). For example, the pole 128 has an end-turn insulator 129 with a bobbin flange 150, the pole 130 has an end-turn insulator 131 with a bobbin flange 152, the pole 132 has an end-turn insulator 133 with a bobbin flange 154, and the pole 134 has an end-turn insulator 135 with a bobbin flange 156. These end-turn insulators and bobbin flanges can be considered as part of the respective poles, and they structurally support the wire windings of the stator 102 and prevent them from “falling off.” In other example implementations, rather than having bobbin flanges, the stator teeth or poles may have a tip shape or configuration (e.g., flared tooth) that enables retaining the wire windings irrespective of the end turn insulator. Some example electric motors of this type may involve powder-coating the stator, and no flange or end turn insulator might be used. Some examples methods of assembling the wire windings may prevent the use of tooth tips, while an appropriatelyshaped slot wedge could still enable the use of the cooling liners described herein in the absence of “flared” tooth tips (or end turn insulators).

[0040] During operation of the electric motor 100, the flow of electric current through the wire windings 142-148 generates a significant amount of heat. The output power of the electric motor 100 may be limited by the ability to transfer heat away from the electric motor 100. As such, it may be desirable to configure electric motors with effective cooling strategies to maintain performance and prevent damage.

[0041] In some cases, cooling oil may be sprayed on the end turns of the wire windings. However, this technique may lead to losses and reduced motor efficiency. In other examples, an electric motor may be completely submerged in cooling oil, including the airgap between the stator and the rotor of the motor. However, this technique may lead to windage losses and reduced motor efficiency. As such, an enhanced cooling configuration may be desirable.

[0042] The slots (e.g., the slots 136-140) between the wire windings 142-148) can be used as fluid channels through which coolant provided through the coolant inlet port 122 can flow axially through the stator 102. Such coolant contacts and absorbs heat from the sides and ends of the wire windings 142-148 before being discharged through the coolant outlet port 124.

[0043] As coolant flows axially through the slots 134-140, the temperature difference between the coolant and the surface temperature of the wire windings 142-148 may cause a thermal boundary layer to form. The thermal boundary layer is a thin layer of fluid that surrounds the hot surface of the wire windings 142-148, where the temperature of the coolant gradually changes due to heat transfer from the wire windings. As the coolant flows over the surface of the wire windings, the coolant particles reach thermal equilibrium with the surface temperature. This transfers energy to the adjacent fluid layer, creating temperature gradients.

[0044] Notably, the thickness of the thermal boundary layer varies and depends on the distance from the surface to where the fluid temperature equals the bulk fluid temperature. Such variation in thickness may reduce the efficiency of heat transfer from the wire windings to the coolant. Particularly, the heat transfer drops substantially in the direction of flow of the coolant.

[0045] Further, thermal boundary resistance, also known as interfacial thermal resistance, which is a measure of how much thermal flow is resisted at the interface between the coolant and the wire windings may also reduce the heat transfer efficiency. As such, it may be desirable to disrupt the thermal boundary layer to enhance heat transfer to the coolant.

[0046] Figure 4 illustrates a partial front view of the stator 102 with cooling liners disposed in the slots between the poles of the stator 102, according to an example implementation. As shown in the partial view of Figure 4, a cooling liner 158 is disposed or inserted into the slot 136, a cooling liner 160 is disposed or inserted into the slot 138, and a cooling liner 162 is disposed or inserted into the slot 140. Similar cooling liners may be disposed in the other slots of the stator 102 as well. The cooling liners are also visible in the front view of Figure IB through the ports of the proximal stator ring 110.

[0047] Figure 5 illustrates a perspective view of the cooling liner 160, according to an example implementation. The other cooling liners of the electric motor 100 can be configured similar to the cooling liner 160.

[0048] As depicted in Figure 5, the cooling liner 160 is generally tee-shaped (T-shaped). Particularly, the cooling liner 160 has a base 164 forming the horizontal part of the tee shape. The cooling liner 160 also has a fin 166 attached to or integral with the base 164, and forming the vertical part of the tee shape.

[0049] A proximal end of the base 164 has a wing or wedge 168. Particularly, the wedge 168 extends laterally on both sides of the base 164 and has a first lateral portion 170 extending from one side and a second lateral portion 172 extending from the other side. Similarly, a distal end of the base 164 may also have a wing or wedge 174 that extends laterally on both sides of the base 164.

[0050] Referring to Figures 4-5 together, the bobbin flanges of the stator poles may have receptacles to receive the lateral portions of the respective cooling liners. For example, the bobbin flange 152 has a receptacle 176 that receives the first lateral portion 170 of the wedge 168, and the bobbin flange 154 has a respective receptacle 178 that receives the second lateral portion 172 of the wedge 168. Similarly, respective wedges of the other cooling liners are accommodated or received within respective receptacles of adjacent bobbin flanges.

[0051] With this configuration, the wedges and the base of the cooling liners cooperate with the bobbin flanges to seal the interior space of the stator 102 such that coolant flowing through the slots (e.g., the 136-140) does not enter the airgap 107 between the stator 102 and the rotor 104, thereby avoiding windage losses. In other words, the cooling liners are coupled to the respective adjacent poles of the stator 102 to prevent coolant leakage into the airgap 107. The sealing of the airgap 107 can be enhanced by adding a sealant to, or at, the interface between the wedges and the bobbin flanges.

[0052] For example, after the wire windings are wrapped around the respective poles of the stator 102, a varnish (e g., a resin) may be applied to the wire windings to hold them in place to stabilize the windings during vibration of the electric motor 100 in operation. Such varnish may flow by capillary action to fill any gaps between the wedges and the bobbin flanges of the respective endturn insulators to further enhance sealing the airgap 107. In other examples, an additional varnish,glue, or sealant may be applied at the interface between the wedges and the bobbin flanges to enhance the sealing of the airgap 107.

[0053] In examples, the cooling liners may further include thermal boundary layer disrupting features, which can also be referred to as a flow turbulator features. For example, referring to Figures 4-5, the cooling liner 160 may have a plurality of pins, such as pin 180, protruding laterally from both sides of the fin 166. As coolant flows through the slots 136-140, the pins may improve heat transfer through mixing the coolant as it flows and disrupting the thermal boundary layer that could form.

[0054] Thus, the configuration shown in Figures 1-5 may provide several advantages. For example, coolant flows through the slots 136-140 axially, and is thus in contact with entire sides of the respective wire windings as opposed to being sprayed to end turns only. This enhances heat transfer from the wire windings to the coolant. Further, the coolant is prevented from seeping or leaking into the airgap 107 between the stator 102 and the rotor 104, thus reducing windage losses and increasing efficiency. Also, the thermal boundary layer disrupting features of the cooling liners may disrupt the thermal boundary layer to enhance thermal transfer.

[0055] The configuration of the cooling liner 160 provided in Figure 5 is an example for illustration. Other cooling liner configurations with similar thermal boundary layer disrupting features are contemplated.

[0056] Figure 6 illustrates a perspective view of a cooling liner 200, according to an example implementation. The cooling liner 200 is similar to the cooling liner 160 in that the cooling liner 200 is also generally tee-shaped (T-shaped) having a base 202 forming the horizontal part of the tee shape. The cooling liner 200 also has a fin 204, attached to or integral with the base 202 and forming the vertical part of the tee shape.

[0057] The cooling liner 200 also includes thermal boundary disruption features in the form of a plurality of slabs, webs, or baffles 206 (rather than pins) protruding laterally from both sides of the fin 204. A baffle can be thin, flat object that is used to direct or obstruct the flow of the coolant. As coolant flows through the slots 136-140, the baffles 206 may improve heat transfer through mixing the coolant as it flows and disrupting the thermal boundary layer that could form.

[0058] Further, as shown in Figure 6, in an example implementation, the baffles may be vertically shifted from each other along the fin 204. For example, a baffle 208 is shifted vertically relative to a baffle 210 and so on. This may cause coolant to zig zag as it flows axially along the sides of the cooling liner 200, further enhancing disruption of the thermal boundary layer. Although the baffles 206 are shown to be perpendicular to the fin 204, in other examples, the baffles may be disposed at respective angles.

[0059] Figure 7 illustrates a perspective view of a cooling liner 300, according to an example implementation. The cooling liner 300 has a base 302 from which a plurality of baffles such as baffle 304 (configured as thermal boundary layer disrupting features) protrude vertically.

[0060] In an example, the baffles may have an airfoil shape. In one example, as depicted, the baffles may be angled to enhance mixing and disruption of the thermal boundary layer, and possibly prevent a thermal boundary layer for forming.

[0061] In an example, as shown, the baffles may be staggered at opposite angles. For example, a baffle 306 may be angled at a 30 degree angle in one direction, while an adjacent baffle 308 is angled at 30 degree angle in an opposite direction, and then the baffle 304 may be angled in a manner similar to the baffle 306. This configuration may further enhance coolant mixing and disruption of the thermal boundary layer.

[0062] The cooling liner 300 may also have wedges at its respective axial ends to facilitate mounting the cooling liner 300 to the respective bobbin flanges of the adjacent poles and seal the airgap 107. For example, the cooling liner 300 has a first wedge 310 at a first end of the cooling liner 300 and a second wedge 312 at a second end (opposite end). The wedges 310, 312 may be inclined downward as shown in Figure 7.

[0063] Figure 8 illustrates a perspective view of a cooling liner 400, according to an example implementation. The cooling liner 400 is similar to the cooling liner 300 in that the cooling liner 400 has a base 402 from which a plurality of baffles, such as baffle 404, configured as thermal boundary layer disrupting features, protrude vertically. Similar to the baffles of the cooling liner 300, the baffles of the cooling liner 400 may also be angled, and may be staggered at opposite angles to enhance mixing and disruption of the thermal boundary layer, and possibly prevent a thermal boundary layer for forming.

[0064] In an example, the cooling liner 400 may have a rail 406 that ties or is coupled to the respective ends (e.g., upward ends, not tied to the base 402) of the baffles together as shown. The rail 406 may have inclined lateral surfaces that might also enhance coolant mixing.

[0065] The cooling liner 400 may also have wedges at its respective axial ends to facilitate mounting the cooling liner 400 to the respective bobbin flanges of the adjacent poles and seal the airgap 107. For example, the cooling liner 400 has a first wedge 408 at a first end of the cooling liner 400 and a second wedge 410 at a second end (opposite end). The wedges 408, 410 may be inclined upward as shown in Figure 8.

[0066] Any of the cooling liners 200, 300, 400 can replace the cooling liners shown in Figures 4-5. Further, features of the cooling liners 160, 200, 300, 400 can be combined. For example, the pins of the cooling liner 160 may be added to the baffles of the cooling liners 200, 300, 400,respectively, to further enhance flow mixing and disruption. Another cooling liner may have a fin similar the fin 166 and the fin 204, with angled baffles protruding laterally therefrom, and so on.

[0067] Figure 9 is a flowchart of a method 500 for assembling and / or operating an electric motor, according to an example implementation. The method 500 can be used to form or assemble the electric motor 100. At least some of the operations of the method 500 can be performed automatically, e.g., via a machine or robot.

[0068] The method 500 may include one or more operations, or actions as illustrated by one or more of blocks 502-510. Although the blocks are illustrated in a sequential order, these blocks may also be performed in parallel, and / or in a different order than those described herein. Also, the various blocks may be combined into fewer blocks, divided into additional blocks, and / or removed based upon the desired implementation. It should be understood that for this and other processes and methods disclosed herein, flowcharts show functionality and operation of one possible implementation of present examples. Alternative implementations are included within the scope of the examples of the present disclosure in which functions may be executed out of order from that shown or discussed, including substantially concurrent or in reverse order, depending on the functionality involved, as would be understood by those reasonably skilled in the art.

[0069] At block 502, the method 500 includes providing the stator 102 of the electric motor 100, wherein the stator 102 has a plurality of poles (e.g., the poles 128, 130, 132, 134) such that a slot (e g., any of the slots 136-140) is formed between each pair of adjacent poles of the plurality of poles to allow coolant flow through the slot. The term “providing” as used herein, and for example with regard to the stator 102 includes any action to make the stator 102 available for use, such asbringing the stator 102 to an apparatus or to a work environment for further processing (e.g., mounting other components).

[0070] At block 504, the method 500 includes wrapping respective wire windings (e.g., the wire windings 142-148) around the plurality of poles.

[0071] At block 506, the method 500 includes positioning the rotor 104 within the stator 102 such that the airgap 107 is formed between the stator and the rotor.

[0072] At block 508, the method 500 includes inserting a cooling liner (e.g., the cooling liner 160, 200, 300, 400) in the slot (e.g., any of the slots 136-140).

[0073] At block 510, the method 500 includes coupling the cooling liner to the adjacent poles to seal the airgap 107, wherein the cooling liner has one or more thermal boundary layer disrupting features (any of the pins or baffles described above with respect to Figures 5-8).

[0074] The method 500 can further include any other steps and operations described throughout herein.

[0075] The detailed description above describes various features and operations of the disclosed systems with reference to the accompanying figures. The illustrative implementations described herein are not meant to be limiting. Certain aspects of the disclosed systems can be arranged and combined in a wide variety of different configurations, all of which are contemplated herein.

[0076] Further, unless context suggests otherwise, the features illustrated in each of the figures may be used in combination with one another. Thus, the figures should be generally viewed as component aspects of one or more overall implementations, with the understanding that not all illustrated features are necessary for each implementation.

[0077] Additionally, any enumeration of elements, blocks, or steps in this specification or the claims is for purposes of clarity. Thus, such enumeration should not be interpreted to require or imply that these elements, blocks, or steps adhere to a particular arrangement or are carried out in a particular order.

[0078] Further, devices or systems may be used or configured to perform functions presented in the figures. In some instances, components of the devices and / or systems may be configured to perform the functions such that the components are actually configured and structured (with hardware and / or software) to enable such performance. In other examples, components of the devices and / or systems may be arranged to be adapted to, capable of, or suited for performing the functions, such as when operated in a specific manner.

[0079] By the term “substantially” or “about” it is meant that the recited characteristic, parameter, or value need not be achieved exactly, but that deviations or variations, including for example, tolerances, measurement error, measurement accuracy limitations and other factors known to those with skill in the art, may occur in amounts that do not preclude the effect the characteristic was intended to provide.

[0080] The arrangements described herein are for purposes of example only. As such, those skilled in the art will appreciate that other arrangements and other elements (e.g., machines, interfaces, operations, orders, and groupings of operations, etc.) can be used instead, and some elements may be omitted altogether according to the desired results. Further, many of the elements that are described are functional entities that may be implemented as discrete or distributed components or in conjunction with other components, in any suitable combination and location.

[0081] While various aspects and implementations have been disclosed herein, other aspects and implementations will be apparent to those skilled in the art. The various aspects andimplementations disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope being indicated by the following claims, along with the full scope of equivalents to which such claims are entitled. Also, the terminology used herein is for the purpose of describing particular implementations only, and is not intended to be limiting.

[0082] Embodiments of the present disclosure can thus relate to one of the enumerated example embodiments (EEEs) listed below.

[0083] EEE 1 is an electric motor comprising: a stator having a plurality of poles such that a slot is formed between each pair of adjacent poles of the plurality of poles; a plurality of wire windings respectively wrapped around the plurality of poles, wherein coolant flows through the slot to cool adjacent wire windings; a rotor, wherein an airgap is formed between the stator and the rotor; and a cooling liner disposed in the slot, wherein the cooling liner is coupled to the adjacent poles to prevent coolant flowing in the slot from entering the airgap, wherein the cooling liner has one or more thermal boundary layer disrupting features.

[0084] EEE 2 is the electric motor of EEE 1, wherein the stator has (i) a coolant inlet port receiving coolant to flow through the slot, and (ii) a coolant outlet port for discharging coolant from the stator.

[0085] EEE 3 is the electric motor of EEE 2, wherein the stator has (i) a proximal end ring having the coolant inlet port, and (ii) a distal end ring having the coolant outlet port.

[0086] EEE 4 is the electric motor of any of EEEs 1-3, each pole of the plurality of poles has an end-turn insulator that electrically insulates a respective wire winding from the pole, and wherein the cooling liner is coupled to the end-turn insulator to seal the airgap.

[0087] EEE 5 is the electric motor of EEE 4, wherein the cooling liner has a wedge, and wherein the end-turn insulator has a receptacle that receives the wedge to couple the cooling liner to the pole.

[0088] EEE 6 is the electric motor of any of EEEs 1-5, wherein the cooling liner comprises: a base; and a fin attached to or integrated with the base.

[0089] EEE 7 is the electric motor of EEE 6, wherein the base has a wedge having at least one lateral portion that is received in a receptacle in a pole of the plurality of poles to couple the cooling liner to the pole.

[0090] EEE 8 is the electric motor of any of EEEs 6-7, wherein the thermal boundary layer disrupting features comprise a plurality of pins protruding laterally from the fin.

[0091] EEE 9 is the electric motor of any of EEEs 6-8, wherein the thermal boundary layer disrupting features comprise a plurality of baffles protruding laterally from the fin.

[0092] EEE 10 is the electric motor of EEE 9, wherein the plurality of baffles protrude at respective angles from the fin.

[0093] EEE 11 is the electric motor of any of EEEs 9-10, wherein the plurality of baffles are staggered at opposite angles.

[0094] EEE 12 is the electric motor of any of EEEs 9-11, wherein the plurality of baffles are shifted vertically relative to each other along the fin.

[0095] EEE 13 is the electric motor of any of EEEs 1-12, wherein the cooling liner comprises: a base, wherein the thermal boundary layer disrupting features comprise a plurality of baffles coupled to the base.

[0096] EEE 14 is the electric motor of EEE 13, wherein the plurality of baffles are staggered at opposite angles.

[0097] EEE 15 is the electric motor of any of EEEs 13-14, further comprising: a rail that is coupled to respective ends of the baffles.

[0098] EEE 16 is a method of assembling and / or operating the electric motor of any of EEEs 1 - 15. For example, the method comprises: providing a stator of an electric motor, wherein the stator has a plurality of poles such that a slot is formed between each pair of adjacent poles of the plurality of poles to allow coolant flow through the slot; wrapping respective wire windings around the plurality of poles; positioning a rotor relative to the stator such that an airgap is formed between the stator and the rotor; inserting a cooling liner in the slot; and coupling the cooling liner to the adjacent poles to seal the airgap, wherein the cooling liner has one or more thermal boundary layer disrupting features.

[0099] EEE 17 is the method of EEE 16, wherein the stator has a coolant inlet port and a coolant outlet port, and wherein the method further comprises: providing coolant through the coolant inlet port; and discharging coolant through the coolant outlet port.

[0100] EEE 18 is the method of any of EEEs 16-17, each pole of the plurality of poles has an end-turn insulator that electrically insulates a respective wire winding from the pole, and wherein coupling the cooling liner to the adjacent poles comprises: coupling the cooling liner to the endturn insulator to seal the airgap.

[0101] EEE 19 is the method of EEE 18, wherein the cooling liner has a wedge, and wherein the end-turn insulator has a receptacle, and wherein coupling the cooling liner to the end-turn insulator comprises: inserting the wedge into the receptacle.

[0102] EEE 20 is the method of EEE 19, wherein the wedge has at least one lateral portion, and wherein inserting the wedge into the receptacle comprises: inserting the at least one lateral portion into the receptacle.

Claims

CLAIMSWhat is claimed is:1 . An el ectri c m otor compri si ng : a stator having a plurality of poles such that a slot is formed between each pair of adjacent poles of the plurality of poles; a plurality of wire windings respectively wrapped around the plurality of poles, wherein coolant flows through the slot to cool adjacent wire windings; a rotor, wherein an airgap is formed between the stator and the rotor; and a cooling liner disposed in the slot, wherein the cooling liner is coupled to the adjacent poles to prevent coolant flowing in the slot from entering the airgap, wherein the cooling liner has one or more thermal boundary layer disrupting features.

2. The electric motor of claim 1 , wherein the stator has (i) a coolant inlet port receiving coolant to flow through the slot, and (ii) a coolant outlet port for discharging coolant from the stator.

3. The electric motor of claim 2, wherein the stator has (i) a proximal end ring having the coolant inlet port, and (ii) a distal end ring having the coolant outlet port.

4. The electric motor of claim 1, each pole of the plurality of poles has an end-turn insulator that electrically insulates a respective wire winding from the pole, and wherein the cooling liner is coupled to the end-turn insulator to seal the airgap.

5. The electric motor of claim 4, wherein the cooling liner has a wedge, and wherein the end-turn insulator has a receptacle that receives the wedge to couple the cooling liner to the pole.

6. The electric motor of claim 1, wherein the cooling liner comprises: a base; and a fin attached to or integrated with the base.

7. The electric motor of claim 6, wherein the base has a wedge having at least one lateral portion that is received in a receptacle in a pole of the plurality of poles to couple the cooling liner to the pole.

8. The electric motor of claim 6, wherein the thermal boundary layer disrupting features comprise a plurality of pins protruding laterally from the fin.

9. The electric motor of claim 6, wherein the thermal boundary layer disrupting features comprise a plurality of baffles protruding laterally from the fin.

10. The electric motor of claim 9, wherein the plurality of baffles protrude at respective angles from the fin.

11. The electric motor of claim 9, wherein the plurality of baffles are staggered at opposite angles.

12. The electric motor of claim 9, wherein the plurality of baffles are shifted vertically relative to each other along the fin.

13. The electric motor of claim 1, wherein the cooling liner comprises: a base, wherein the thermal boundary layer disrupting features comprise a plurality of baffles coupled to the base.

14. The electric motor of claim 13, wherein the plurality of baffles are staggered at opposite angles.

15. The electric motor of claim 13, further comprising: a rail that is coupled to respective ends of the baffles.

16. A method comprising: providing a stator of an electric motor, wherein the stator has a plurality of poles such that a slot is formed between each pair of adjacent poles of the plurality of poles to allow coolant flow through the slot; wrapping respective wire windings around the plurality of poles; positioning a rotor relative to the stator such that an airgap is formed between the stator and the rotor; inserting a cooling liner in the slot; and coupling the cooling liner to the adjacent poles to seal the airgap, wherein the cooling liner has one or more thermal boundary layer disrupting features.

17. The method of claim 16, wherein the stator has a coolant inlet port and a coolant outlet port, and wherein the method further comprises: providing coolant through the coolant inlet port; and discharging coolant through the coolant outlet port.

18. The method of claim 16, each pole of the plurality of poles has an end-turn insulator that electrically insulates a respective wire winding from the pole, and wherein coupling the cooling liner to the adjacent poles comprises: coupling the cooling liner to the end-turn insulator to seal the airgap.

19. The method of claim 18, wherein the cooling liner has a wedge, and wherein the end-turn insulator has a receptacle, and wherein coupling the cooling liner to the end-turn insulator comprises: inserting the wedge into the receptacle.

20. The method of claim 19, wherein the wedge has at least one lateral portion, and wherein inserting the wedge into the receptacle comprises: inserting the at least one lateral portion into the receptacle.

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