Cooling systems for e-machines having a winding arrangement

Abstract

An e-machine including a stator core (154) having a slot and a plurality of winding members received in the slot, the winding members defining fluid passageways (171) within the slot. The e-machine further includes a fluid coolant system configured to provide fluid coolant to the fluid passageways within the slot. The e-machine includes a circumferential channel at least partially formed by the housing (124, 194). The channel includes a plurality of fluid outlets arranged to allow fluid coolant to flow therethrough so as to flood the stator core with fluid coolant supplied from the fluid coolant system.

Description

PATENT APPLICATIONAttorney Docket No. GAR GOO1538 IACOOLING SYSTEMS LOR E-M ACHINES HAVING A WINDING ARRANGEMENTTECHNICAL FIELD

[0001] The present disclosure relates, generally, to an e-machine and, more particularly, to an e-machine system with a windings arrangement in which segments of the winding are arranged to form fluid passageways within a slot of a stator of the e-machine for flow of fluid therethrough, also known as direct slot cooling.BACKGROUND

[0002] E-machines, such as electric motors, electric generators, and combination electric motor / generators, are provided for a variety of uses. For example, electric traction motors are used in electric vehicles, electric locomotives, and so on. Electric generators also have many industrial uses.

[0003] E-machine systems typically generate heat during operation. Additionally, e-machine systems may operate in high-temperature environments. Elevated temperatures may hinder performance and / or cause other disadvantages associated with the e-machine. Thus, it is desirable to include cooling features in the e-machine. However, the design and provision of such cooling features remains challenging. There may be detrimental increases in costs, part count, device complexity, size, bulkiness, and / or weight if such cooling features are included.

[0004] Thus, there remains a need for an e-machine system that provides effective cooling. There also remains a need for e-machine systems where the cooling features are provided in a relatively compact, low-weight arrangement. There is also a need for an e-machine system including cooling features that may be manufactured with high efficiency and with reduced costs and manufacturing time.BRIEF SUMMARY

[0005] This summary is provided to describe select concepts in a simplified form that are further described in the Detailed Description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.PATENT APPLICATIONAttorney Docket No. GAR GOO1538 IA

[0006] According to a first aspect of the invention, there is provided an e-machine comprising a rotor member; a stator core having a first axial end and a second axial end that are separated along a longitudinal axis, the stator core having a slot that extends between the first axial end and the second axial end; and a plurality of winding members, the plurality of winding members comprising a plurality of segments that are received in the slot and that extend between the first axial end and the second axial end of the stator core. The plurality of segments are disposed in an arrangement that defines one or more fluid passageways within the slot, the one or more fluid passageways extending between the first axial end and the second axial end of the stator core. The e-machine includes a housing that at least partially surrounds the stator core and the plurality of winding members, where the housing includes a fluid inlet and a fluid outlet. The e-machine further includes a fluid coolant system configured to provide fluid coolant to the fluid inlet. The e-machine includes a channel at least partially formed by the housing, which channel extends circumferentially about the longitudinal axis. The channel is fluidically connected to the fluid inlet so as to receive fluid coolant therefrom. The channel includes a plurality of fluid outlets arranged to allow fluid coolant to flow therethrough so as to flood the stator core with fluid coolant supplied from the fluid coolant system.

[0007] In an embodiment, the plurality of fluid outlets are evenly / uniformly distributed about a circumference of the channel.

[0008] In an embodiment combinable with the above embodiments, the housing comprises an e-machine housing and a bearing housing, the e-machine housing and bearing housing configured to together surround the stator core and a bearing upon which the rotor member of the e-machine is supported.

[0009] In an embodiment combinable with the above embodiments, the channel is formed from a groove in the bearing housing and a distributor member covering the groove. The distributor member is preferably formed from metal or plastic. In an embodiment, the plurality of fluid outlets are formed in the distributor member. In an alternative embodiment, the plurality of fluid outlets are formed in the groove formed in the bearing housing.

[0010] In an embodiment, combinable with some of the above embodiments, the channel is formed from a groove in the e-machine housing and a distribution member covering the groove. The distributor member is preferably formed from metal or plastic. In an embodiment, the plurality of fluid outlets are formed in the distributor member. In anPATENT APPLICATIONAttorney Docket No. GAR GOO1538 IAalternative embodiment, the plurality of fluid outlets are formed in the groove formed in the e-machine housing.

[0011] In an embodiment combinable with the above embodiments, the e-machine includes a seal arranged between the plurality of fluid outlets and the rotor member, the seal configured to prevent fluid coolant from a flooded area around the stator core from flowing to the rotor member.

[0012] In an embodiment combinable with the above embodiments, the stator core comprises a plurality of slots, wherein each one of the plurality of fluid outlets is positioned proximate to a respective one of the plurality of slots.

[0013] In an embodiment combinable with the above embodiments, the e-machine is an electric motor.

[0014] In an embodiment combinable with the above embodiments, the e-machine is an electric generator.

[0015] In an embodiment combinable with the above embodiments, the e-machine includes a volume occupying member configured to reduce a volume inside the housing.

[0016] In an embodiment combinable with the above embodiments, the plurality of fluid outlets have a circular shape and are aligned parallel to the longitudinal axis.

[0017] According to a second aspect of the invention, there is provided an e-machine comprising: a rotor member; a stator core having a first axial end and a second axial end that are separated along a longitudinal axis, the stator core having a slot that extends between the first axial end and the second axial end and a cooling passage fluidically isolated from the slot; and a plurality of winding members, the plurality of winding members comprising a plurality of segments that are received in the slot and that extend between the first axial end and the second axial end. The e-machine also includes a housing at least partially surrounding the stator core and the plurality of winding members. The housing includes a fluid inlet and a fluid outlet. The e-machine is configured to be connected to a fluid coolant system that is configured to provide fluid coolant to the fluid inlet. The e-machine also includes a channel at least partially formed by the housing, the channel extending circumferentially about the longitudinal axis, the channel fluidically connected to the fluid inlet to receive fluid coolant therefrom, wherein the channel comprises a plurality of fluid outlets arranged to allow fluid coolant to flow therethrough so as to flood the stator core with fluid coolant. The slot is fluidically isolated from the plurality of fluid outlets. The cooling passage is fluidically connected to the plurality of fluid outlets.PATENT APPLICATIONAttorney Docket No. GAR GOO1538 IA

[0018] In an embodiment combinable with the above aspect, the plurality of fluid outlets are evenly distributed about a circumference of the channel.

[0019] In an embodiment combinable with the above aspect and embodiment, the housing comprises an e-machine housing and a bearing housing, the e-machine housing and bearing housing being configured to together surround the stator core and a bearing upon which the rotor member of the e-machine is supported.

[0020] In an embodiment combinable with the above aspect and embodiments, the channel is formed from a groove in the bearing housing and a distributor member covering the groove, optionally wherein the distributor member is formed from metal or plastic.

[0021] In an embodiment combinable with the above aspect and embodiments, the plurality of fluid outlets are formed in the distributor member or in the groove.

[0022] In an embodiment combinable with the above aspect and embodiments, the channel is formed from a groove in the e-machine housing and a distribution member covering the groove, optionally wherein the distributor member is formed from metal or plastic.

[0023] In an embodiment combinable with the above aspect and embodiments, the stator core comprises a plurality of cooling passages, and wherein each one of the plurality of fluid outlets is positioned proximate to a respective one of the plurality of cooling passages.

[0024] In an embodiment combinable with the above aspect and embodiments, the e-machine is an electric motor or an electric generator.

[0025] In an embodiment combinable with the above aspect and embodiments, the e-machine further includes a volume occupying member configured to reduce a volume inside the housing.

[0026] In an embodiment combinable with the above aspect and embodiments, the plurality of fluid outlets have a circular shape and are aligned either parallel to or at a non-zero angle to the longitudinal axis.

[0027] Other desirable features and characteristics of the present disclosure will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the preceding background.BRIEF DESCRIPTION OF DRAWINGS

[0028] The present disclosure will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and wherein:PATENT APPLICATIONAttorney Docket No. GAR GOO1538 IA

[0029] FIG. 1 is a schematic illustration of an e-machine;

[0030] FIG. 2 is a cross-section view of an e-machine according to embodiments;

[0031] FIGs. 3 A to 3E show slot winding configurations that allow for the formation of one or more fluid passageways within each slot of a stator core;

[0032] FIG. 4 is a cross-sectional view of a channel and distributor member according to embodiments;

[0033] FIG. 5 is another cross-sectional view of a channel and distributor member according to embodiments;

[0034] FIG. 6 is a cross-sectional view of an alternative channel and distributor member arrangement according to embodiments;

[0035] FIG. 7 is a view of a part of an e-machine according to embodiments; and

[0036] FIG. 8 is a schematic illustration of an e-machine in accordance with another embodiment.DETAILED DESCRIPTION

[0037] The following detailed description is merely exemplary in nature and is not intended to limit the present disclosure or the application and uses of the present disclosure. As used herein, the word “exemplary” means “serving as an example, instance, or illustration.” Thus, any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments. All of the embodiments described herein are exemplary embodiments provided to enable persons skilled in the art to make or use the present disclosure and not to limit the scope of the present disclosure, which is defined by the claims. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, brief summary, or the following detailed description.

[0038] Broadly, example embodiments disclosed herein include an e-machine system, such as an electric motor system, having features that provide effective cooling for efficient high-temperature operation of the e-machine.

[0039] The stator member of the e-machine includes a stator core with a plurality of slots (i.e., grooves, passages, etc.) that extend between a first axial end and a second axial end of the stator core. The slots may extend along a respective longitudinal axis that is parallel to an axis of rotation of the rotating group of the e-machine. The slots may be circumferentiallyPATENT APPLICATIONAttorney Docket No. GAR GOO1538 IAuniformly distributed (e.g., spaced equally) about the axis of rotation. In various embodiments, the slots may be open to the inner radial surface of the stator core.

[0040] The stator core includes a plurality of winding members comprising a plurality of longitudinal segments that are received in respective slots. In at least one of the slots, there may be a group of longitudinal segments. These longitudinal segments have a cross-sectional shape (taken through the longitudinal axis of the slot). These longitudinal segments may be disposed (i.e., layered, oriented, etc.) in an abutting arrangement. In embodiments, the shapes and arrangements of the winding members provide spacing between the adjacent longitudinal segments. Where such spacing is provided, fluid passageways are defined along the slots. Additionally, fluid passageways may be defined between neighboring ones of the longitudinal segments of the windings.

[0041] The longitudinal segments may be disposed parallel to the axis of rotation (longitudinal axis) of the rotating group. Alternatively, the longitudinal segments may be disposed in a skewed configuration, with some or all of the longitudinal segments forming a non-zero angle with respect to the axis of rotation (longitudinal axis).

[0042] The e-machine system includes a fluid coolant system that provides a fluid coolant (refrigerant, coolant, oil, air, other gas, other liquid, etc.) to the e-machine. This fluid coolant may be provided to the slots so as to flow amongst the longitudinal segments of the windings. Thus, fluid coolant may be provided directly to flood the windings and the stator core for effective cooling via direct slot cooling. In embodiments, the fluid coolant system provides pressurized cooling fluid to the e-machine.

[0043] An e-machine having such features may be relatively compact and lightweight. The e-machine may also provide manufacturing benefits, such as a relatively low part count, as well as ease of assembly, installation, repair, and replacement, as will be explained in more detail below.

[0044] FIG. 1 is a schematic view of an e-machine system 100 according to example embodiments of the present disclosure. The e-machine system 100 may have a variety of configurations. In some embodiments, the e-machine system 100 may be configured as a traction drive system 102 that is included, for example, on a vehicle 106. Thus, the traction drive system 102 may be configured for driving one or more wheels 104 of the vehicle 106. More specifically, the wheels 104 may be included at opposite ends of an axle 111, and a chassis 107 may be supported on the wheels 104 by a suspension system (not shown). The vehicle 106 may be an electric car, truck, van, motorcycle, boat, or other vehicle. However, itPATENT APPLICATIONAttorney Docket No. GAR GOO1538 IAwill be appreciated that the e-machine system 100 may be configured otherwise without departing from the scope of the present disclosure, such as in the form of an electric generator that is not included on a vehicle.

[0045] Generally, the e-machine system 100 may include a housing 125. The housing 125 may include an e-machine housing 124 with a cavity 129 defined therein. The e-machine system 100 may also include an e-machine 110 that is received within the cavity 129 and housed within the e-machine housing 124.

[0046] The e-machine 110 may be an electric motor 112. For example, in some embodiments, the electric motor 112 may be an AC three-phase electric motor. However, it will be appreciated that the e-machine 110 may be configured otherwise. The e-machine 110 may alternatively be configured as an electric generator. Furthermore, the e-machine 110 may be operable in some modes as a motor and in additional modes as a generator. The e-machine 110 includes a rotor member 118 and a stator member 119 that are housed within the cavity 129 of the e-machine housing 124.

[0047] The rotor member 118 may be supported on a shaft 116, and the shaft 116 is supported for rotation about a longitudinal axis 109 within the e-machine housing 124. The stator member 119 of the e-machine 110 may be fixed within the e-machine housing 124 and at least partly surrounds the rotor member 118 and the shaft 116. In embodiments in which the e-machine 110 is an electric motor 112, the shaft 116 may be referred to as an output shaft 116 of the electric motor 112. In some embodiments, such as when the e-machine system 100 is mounted on a vehicle 106, a gear connection member 128 (e.g., a gear, a spline on the shaft 116, or other part with gear teeth features) may be operably supported on the shaft 116.

[0048] In various embodiments, the e-machine system 100 includes a transmission 130. The transmission 130 may include a geartrain 132 that is housed within a gearbox housing 136 of the housing 125. The gearbox housing 136 may be attached (e.g., fixed) to a side wall 127 of the e-machine housing 124.

[0049] The geartrain 132 may operatively connect the e-machine 110 and the axle 111 and may transmit power therebetween. The e-machine 110 may be coupled to the wheels 104 via the transmission 130. The geartrain 132 may be attached to the gear connection member 128 and to the axle 111. The gearbox housing 136 and the e-machine housing 124 may be moveably supported on the axle 111 by one or more bearings 114 (e.g., a bearing sleeve, suspension tube, etc.) such that the axle 111 may rotate relative thereto.PATENT APPLICATIONAttorney Docket No. GAR GOO1538 IA

[0050] During operation, the electric motor 112 may rotatably drive the shaft 116 and the gear connection member 128 supported thereon. This rotational power may transfer to the geartrain 132, which may transmit the power to the axle 111 to rotate the wheels 104 and propel the vehicle 106. These operations may be controlled by a control system 133. The control system 133 may control speed of the motor 112 and / or other functions of the motor 112.

[0051] Furthermore, the e-machine system 100 may include a fluid coolant system 140. The fluid coolant system 140 may be configured for circulating a fluid, such as a fluid coolant. The fluid coolant may be oil, for example. In embodiments, the fluid coolant system 140 is configured to supply pressurized fluid coolant, and may comprise a pump or other such means for delivering pressurized fluid coolant.

[0052] The fluid coolant system 140 is coupled to the stator member 119. Accordingly, the fluid coolant system 140 is configured to provide cooling to the stator member 119. This, in turn, provides a degree of cooling to the rotor member 118, to bearings, and / or to other adjacent areas of the e-machine 110.

[0053] FIG. 2 shows a schematic of half of the e-machine 100 with the longitudinal axis 109 at the bottom of the figure. As shown in FIG. 2, the e-machine 100 includes a stator core 154. The stator core 154 is typically hollow and cylindrical and includes an outer radial surface 156, an inner radial surface 158, a first axial end 160, and a second axial end 162. In various embodiments, the stator core 154 comprises a plurality of disc-shaped laminations that are bonded together in a stacked configuration and are arranged along the axis 109 so as to collectively define the outer radial surface 156 and the inner radial surface 158. It will be appreciated that the widths of the disc-shaped laminations may vary, and that the widths of the disc-shaped laminations may be chosen based, for example, on manufacturing considerations. By forming the stator core 154 from disc-shaped laminations, the stator core 154 may be made both light-weight and relatively inexpensive, and the manufacturing process used to make the stator core 154 may be simplified due to the ability to simply bond disc-shaped members together to form the laminated core.

[0054] As shown in FIG. 2, the stator core 154 includes at least one, and preferably a plurality of, slot(s) 164 (i.e., grooves, passages, etc.). It will be appreciated that the laminations of the stator core 154 may individually include notches that, when stacked together, collectively define the slots 164. The slots may have various cross-sections, for example curved or rectangular cross-sections. In some embodiments, the slots 164 may bePATENT APPLICATIONAttorney Docket No. GAR GOO1538 IAopen at the inner radial surface 158. Alternatively, the slots 164 may be closed at the inner radial surface 158. Each slot 164 extends parallel to the longitudinal axis 109 between the first axial end 160 and the second axial end 162 of the stator core 154. The slots 164 may be open at the first axial end 160 and the second axial end 162 of the stator core 154. The plurality of slots 164 may be disposed in a spaced arrangement (e.g., be equally spaced) about the longitudinal axis 109.

[0055] The stator core 154 may further include a plurality of windings (i.e., winding members, wiring members, etc.). The windings are electrically conductive. The windings are arranged in a plurality of coils that wrap back-and-forth between first and second axial ends 160, 162 of the stator core 154 and between different ones of the plurality of slots 164.

[0056] Accordingly, the windings include a plurality of longitudinal segments 172 that are received in the slots 164 of the stator core 154 and that extend generally along the axis of the respective slot 164. As noted above, alternatively the longitudinal segments 172 may have a skewed arrangement where at least some of the longitudinal segments 172 form a non-zero angle with the longitudinal axis 109.

[0057] The windings also include a plurality of first end windings 188 proximate to the first axial end 160 of the stator core 154 and a plurality of second end windings 189 proximate to the second axial end 162. The first end windings 188 connect respective pairs of longitudinal segments 172 in different slots 164, and the first end windings 188 may be disposed outside of the stator core 154 on the first axial end 160. In some embodiments, at least one of the first end windings 188 and second end windings 189 may extend away from the first axial end 160 to electrically connect to the control system 133. Furthermore, the second end windings 189 connect respective pairs of the longitudinal segments 172 in different slots 164. The second end windings 189 may be disposed outside the stator core 154 at the second axial end 162. The first and second end windings 188, 189 electrically connect ones of the longitudinal segments 172 for operation of the stator member 119 and for operative connection to the control system 133.

[0058] The longitudinal segments are arranged in a manner so as to define fluid passageways therethrough. Example arrangements of longitudinal segments 172 that define fluid passageways 171 therethrough are shown in FIGs. 3 A to 3E. As can be seen in each of FIGs.3 A to 3E, the longitudinal segments 172 may have various cross-sectional shapes that, when arranged in a certain manner, allow for a plurality of fluid passageways 171 to be defined therethrough. FIGs. 3 A and 3B show the longitudinal segments 172 being arranged within aPATENT APPLICATIONAttorney Docket No. GAR GOO1538 IAslot 164 of the stator core 154, whilst FIGs. 3C, 3D and 3E show example alternative shapes and arrangements of longitudinal segments 172 that define a plurality of fluid passageways 171 therethrough.

[0059] The longitudinal segments 172 may be formed, shaped, and provided with the cross-sectional profiles necessary to form fluid passageways 171 therethrough in a number of ways without departing from the scope of the present disclosure. For example, wire may be extruded or drawn through a die to shape the cross sectional profile of the longitudinal segments 172. Once shaped, the plurality of windings may be provided on the stator core 154. As shown in FIGs. 3 A to 3E, the longitudinal segments 172 may be arranged within the slots 164 in a layered or radially-stacked arrangement. The longitudinal segments 172 may abut each other in the arrangement. The longitudinal segments 172 may be aligned with each other to define the fluid passageways 171, or may be misaligned. The cross-sectional profiles of the longitudinal segments 172 may have integrally-included features such as ridges or grooves that define fluid passages between neighboring pairs of the segments 172.

[0060] Referring again to FIG. 1, the fluid coolant system 140 may be fluidly connected to the fluid passageways 171 of the stator member 119 to provide fluid coolant thereto. As noted above, the fluid coolant provided by the fluid coolant system 140 may be pressurized. As shown in FIG. 2, the e-machine housing 124 may include a fluid inlet 142 and a fluid outlet 144. The fluid inlet 142 and the fluid outlet 144 may be spaced apart along the axis 109. The fluid inlet 142 and the fluid outlet 144 may be disposed on the same side of the axis 109. Although FIG. 2 shows the fluid inlet 142 and the fluid outlet 144 on the same side of the e-machine housing 124, it will be appreciated that other positions for the fluid inlet 142 and the fluid outlet 144 are possible. For example, the fluid inlet 142 and the fluid outlet 144 may be located on opposite sides of the e-machine 100, or in alternative positions about the e-machine 100. For example, referring to FIG. 1, the fluid outlet 144 may alternatively be arranged within the gearbox housing 136 to allow for gears to be lubricated by the fluid coolant.

[0061] In the embodiment of FIG. 2, the e-machine 100 includes an e-machine housing 124 that surrounds the stator core 154 and a bearing housing 194 that includes one or more bearings (not shown) to support a rotor member of the e-machine 100. In the embodiment of FIG. 2, the fluid inlet 142 is formed in the bearing housing 194 and the fluid outlet 144 is formed in the e-machine housing 124. However, it will be appreciated that the fluid inlet 142 and the fluid outlet 144 may alternatively be arranged in the alternative configuration with thePATENT APPLICATIONAttorney Docket No. GAR GOO1538 IAfluid inlet 142 being formed in the e-machine housing 124 and the fluid outlet 144 being formed in the bearing housing 194. It will further be appreciated that both of the fluid inlet 142 and the fluid outlet 144 may be formed in one of the e-machine housing 124 and the bearing housing 194. It will also be appreciated that the e-machine housing 124 and the bearing housing 194 may be formed as one piece.

[0062] In embodiments, the coolant inlet 142 and the fluid outlet 144 are fluidly connected to the slots 164 and, thus, to the fluid passageways 171 defined through the longitudinal segments 172 arranged within the slots. Accordingly, during operation, fluid coolant supplied through the inlet 142 is able to flow around, between, through and amongst the longitudinal segments 172 when the fluid coolant floods the stator core. This fluid coolant receives heat as it flows longitudinally through the slots 164 before exiting via the fluid outlet 144.

[0063] The e-machine 100 further includes a channel 200 fluidically connected to the fluid inlet 142 such that the channel 200 may receive fluid coolant from the fluid coolant system 140 via the fluid inlet 142. The channel 200 extends circumferentially around the axis 109. The channel 200 includes a plurality of fluid outlets 202 which fluidically connect the channel 200 to a cavity inside the e-machine housing 124 within which the stator core 154 is disposed. The fluid outlets 202 are preferably distributed in a uniform manner about the axis 109 (i.e., equally spaced about the circumference of the channel 200) in order to improve the uniformity of flow of fluid coolant through each of the slots 164. The plurality of fluid outlets 202 may have substantially the same size and shape as each other.

[0064] By distributing the plurality of fluid outlets 202 in a uniform manner about the circumference of the channel 200, the pressure distribution in flooded areas of the stator core may be made more uniform in order to increase the uniformity of temperature and cooling of the stator core 154, as will be explained in more detail below. In an alternative embodiment, the plurality of fluid outlets 202 are arranged in a non-uniform, staggered pattern about the axis 109. The size and shape of the plurality of fluid outlets 202 of the channel 200 may be altered in order to increase the flow rate of fluid coolant out of the plurality of fluid outlets 202. Additionally, only some of the plurality of fluid outlets 202 may be altered. For example, a subset of plurality of fluid outlets 202 may be increased or decreased in size as compared to the remaining plurality of fluid outlets 202. In this manner, the mass flow rate of fluid coolant may be selectively increased or decreased in various areas in order to selectively increase cooling to “hot-spots” of the stator core 154. Additionally or alternatively, the anglePATENT APPLICATIONAttorney Docket No. GAR GOO1538 IAand position of various fluid outlets 202 of some or all of the plurality of fluid outlets may be varied to selectively increase cooling to hot-spots of the stator core 154.

[0065] During operation, fluid coolant is received at the fluid inlet 142 from the fluid coolant system 140. Fluid coolant flows from the fluid inlet 142 to the channel 200 which extends circumferentially about the axis 109. Fluid coolant then flows axially out of the fluid outlets 202 formed in the channel 200 so as to flood the first axial end 160 of the stator core 154 and the end winding 188 at the first axial end 160. Fluid coolant then flows through the fluid passageways 171 formed within the slots 164 of the stator core 154. Accordingly, fluid coolant received via the fluid inlet 142 may flow directly over, between, and amongst the longitudinal segments 172 as the fluid coolant flows longitudinally along the stator core 154. Fluid coolant may then exit the stator core 154 at the second axial end 162 of the stator core so as to flood the second axial end 162 of the stator core 154 and the end winding 189 at the second axial end 162 of the stator core 154. Fluid coolant may then exit the e-machine via the fluid outlet 144. Accordingly, the fluid coolant system 140 may effectively cool the e-machine system 100. Furthermore, the e-machine system 100 may be compact and lightweight. Also, the part count may be relatively low, and the e-machine system 100 may be manufactured with high efficiency.

[0066] As will be appreciated by one of skill in this technical field, the technique of cooling by flooding of the stator core 154 is different from other cooling techniques, such as spraying liquid coolant onto various areas of the stator core 154. Flooding of the stator core 154 with liquid coolant increases the contact surface area between the coolant and the stator core as compared to spray cooling techniques, which provides more uniform and more effective heat removal. Furthermore, flooding of the stator core tends to reduce temperature profile differences in the stator core, leading to a more uniform heat distribution in the stator core as compared to spray cooling techniques. However, flooding of the stator core 154 with liquid coolant does increase the quantity of fluid coolant required for cooling of the stator core 154 and also increases the risk of leakage of fluid coolant to undesired locations. It is therefore desirable that adequate sealing is provided to prevent leakage of fluid coolant from the area around the stator core 154 to other areas of the e-machine, such as the rotor member.

[0067] In order to mitigate against fluid coolant leakage, in some embodiments a seal 250 is disposed between the flooded areas of the stator core 154 and a rotor member (not shown in this figure) of the e-machine to prevent fluid coolant from flowing from the flooded areas of the stator core 154 to the rotor member. In embodiments, this seal 250 is formed from a metalPATENT APPLICATIONAttorney Docket No. GAR GOO1538 IAor plastic member that extends circumferentially about the axis 109. It will be appreciated that other types of sealing solution are possible, and the illustrated seal is for exemplary purposes only.

[0068] In FIG. 2, the channel 200 is formed from the combination of a groove formed in the bearing housing 194 and a distributor member 300. The distributor member 300 is fixed over the groove. The distributor member 300 has the plurality of fluid outlets 202 formed therein. In this manner, the channel 200 and the plurality of fluid outlets 202 may be formed from only a few components in an efficient manufacturing technique that only requires attaching the distributor member 300 over a pre-existing groove in order to form the channel 200. In an embodiment, the distributor member 300 is formed from plastic. In an alternative embodiment, the distributor member 300 is formed from metal.

[0069] FIG. 4 of the application shows a cutaway cross section of the distributor member 300 and the groove formed in the bearing housing 194. As can be seen in FIG. 4, when the distributor member 300 is attached to the bearing housing 194, the combination of the distributor member 300 and the groove in the bearing housing 194 forms a channel 200 through which fluid coolant may flow via the fluid inlet 142. A plurality of fluid outlets 202 are formed in the distributor member 300 to allow fluid coolant to flow out of the channel 200 and to flood the stator core 154.

[0070] FIG. 5 shows a cross section of the distributor member 300 and the bearing housing 194, with the groove in the bearing housing 194 not visible. As can be seen in FIG. 5, the distributor member 300 is attached to the bearing housing 194 via attachment means 350. The attachment means 350 may comprise mechanical fasteners such as screws, bolts, rivets, clips, interference fit recesses and protrusions etc. Additionally or alternatively, the attachment means 350 may comprises non-mechanical fasteners such as glue, epoxy, or another such non-mechanical fastener.

[0071] Whilst the embodiment shown in FIGs. 2 to 5 utilizes a groove formed in the bearing housing 194 to partly form the channel 200, it will be appreciated that other arrangements are possible. For example, the channel 200 may be formed through the use of a groove formed in the e-machine housing 124.

[0072] It will be appreciated that, whilst the above explanation is provided with respect to a single slot 164, the stator core 154 typically includes multiple slots 164 spaced circumferentially about the longitudinal axis 109.PATENT APPLICATIONAttorney Docket No. GAR GOO1538 IA

[0073] Furthermore, whilst the embodiment shown in FIGs. 2 to 5 includes the plurality of fluid outlets 202 formed in the distributor member 300, other arrangements are possible. FIG.6 shows views of an alternative embodiment where a groove is formed in the bearing housing 194, which groove projects toward the stator core 1154. The groove cooperates with an attached, externally located distributor member 1300 to form a channel 1200. The groove includes a plurality of fluid outlets 1202 formed therein. During operation, fluid coolant located in the channel 1200 exits the groove via the plurality of fluid outlets 1202 formed in the groove so as to flood the stator core 1154.

[0074] Turning to FIG. 7, a modification combinable with either of the above embodiments is shown. In FIG. 7, a volume-occupying member 400 is disposed about at least one of the end windings 188, 189. The volume-occupying member 400 is included to reduce the volume of the cavity inside the e-machine housing 124 that must be flooded by the fluid coolant exiting through the plurality of fluid outlets of the channel.

[0075] FIG. 8 shows an e-machine in accordance with alternative embodiment of the invention. As will be appreciated from the below explanation of the e-machine of FIG. 8, the e-machine of this embodiment is similar to the above-described embodiment of the e-machine, with the difference that fluid coolant is not provided to slots of the stator core and is instead provided to dedicated cooling passages that are fluidically isolated from the slots of the stator core.

[0076] FIG. 8 shows a schematic of half of an e-machine 1000 with the longitudinal axis 1109 at the bottom of the figure. As shown in FIG. 8, the e-machine 1000 includes a stator core 1154. The stator core 1154 is typically cylindrical and includes an outer radial surface 1156, an inner radial surface 1158, a first axial end 1160, and a second axial end 1162. In various embodiments, the stator core 1154 comprises a plurality of disc-shaped laminations that are bonded together in a stacked configuration and are arranged along the axis 1109 so as to collectively define the outer radial surface 1156 and the inner radial surface 1158. It will be appreciated that the widths of the disc-shaped laminations may vary, and that the widths of the disc-shaped laminations may be chosen based, for example, on manufacturing considerations. By forming the stator core 1154 from disc-shaped laminations, the stator core 1154 may be made both light-weight and relatively inexpensive, and the manufacturing process used to make the stator core 1154 may be simplified due to the ability to simply bond disc-shaped members together to form the laminated core.PATENT APPLICATIONAttorney Docket No. GAR GOO1538 IA

[0077] As shown in FIG. 8, the stator core 1154 includes at least one, and preferably a plurality of, slot(s) 1164 (i.e., grooves, passages, etc.). It will be appreciated that the laminations of the stator core 1154 may individually include notches that, when stacked together, collectively define the slots 1164. The slots may have various cross-sections, for example curved or rectangular cross-sections. In some embodiments, the slots 1164 may be open at the inner radial surface 1158. Alternatively, the slots 1164 may be closed at the inner radial surface 1158. Each slot 1164 extends parallel to the longitudinal axis 1109 between the first axial end 1160 and the second axial end 1162 of the stator core 1154. The slots 1164 may be open at the first axial end 1160 and the second axial end 1162 of the stator core 1154. The plurality of slots 1164 may be disposed in a spaced arrangement (e.g., be equally spaced) about the longitudinal axis 1109.

[0078] The stator core 1154 further includes a plurality of windings (i.e., winding members, wiring members, etc.). The windings are electrically conductive. The windings are arranged in a plurality of coils that wrap back-and-forth between first and second axial ends 1160, 1162 of the stator core 1154 and between different ones of the plurality of slots 1164.

[0079] Accordingly, the windings include a plurality of longitudinal segments 1172 that are received in the slots 1164 of the stator core 1154 and that extend generally along the axis of the respective slot 1164. Alternatively, the longitudinal segments 1172 may have a skewed arrangement where at least some of the longitudinal segments 1172 form a non-zero angle with the longitudinal axis 1109.

[0080] The windings also include a plurality of first end windings 1188 proximate to the first axial end 1160 of the stator core 1154 and a plurality of second end windings 1189 proximate to the second axial end 1162. The first end windings 1188 connect respective pairs of longitudinal segments 1172 in different slots 1164, and the first end windings 1188 may be disposed outside of the stator core 1154 on the first axial end 1160. In some embodiments, at least one of the first end windings 1188 and second end windings 1189 may extend away from the first axial end 1160 to electrically connect to a control system. Furthermore, the second end windings 1189 connect respective pairs of the longitudinal segments 1172 in different slots 1164. The second end windings 1189 may be disposed outside the stator core 1154 at the second axial end 1162. The first and second end windings 1188, 1189 electrically connect ones of the longitudinal segments 1172 to the control system.

[0081] The e-machine 1000 includes a cooling passage 1180 that is fluidically isolated from the slot 1164. The cooling passage 1180 is configured to receive fluid coolant from a fluidPATENT APPLICATIONAttorney Docket No. GAR GOO1538 IAcoolant system (not shown in this figure). Fluid coolant, flowing through the cooling passage 1180, cools the longitudinal segments 1172 in the stator core 1154 via a technique known as “indirect slot cooling”.

[0082] In the embodiment of FIG. 8, the e-machine 1100 includes an e-machine housing 1124 that surrounds the stator core 1154 and a bearing housing 1194 that includes one or more bearings (not shown) to support a rotor member of the e-machine 1000. In the embodiment of FIG. 8, the fluid inlet 1142 is formed in the bearing housing 1194 and the fluid outlet 1144 is formed in the e-machine housing 1124. However, it will be appreciated that the fluid inlet 1142 and the fluid outlet 1144 may alternatively be arranged in the alternative configuration with the fluid inlet 1142 being formed in the e-machine housing 1124 and the fluid outlet 1144 being formed in the bearing housing 1194. It will further be appreciated that both of the fluid inlet 1142 and the fluid outlet 1144 may be formed in one of the e-machine housing 1124 and the bearing housing 1194. It will also be appreciated that the e-machine housing 1124 and the bearing housing 1194 may be formed as one piece.

[0083] The fluid inlet 1142 and the fluid outlet 1144 are fluidly connected to the cooling passage 1180. Accordingly, during operation, fluid coolant supplied through the fluid inlet 1142 is able to flow through the cooling passage 1180 when the fluid coolant floods the stator core 1154. This fluid coolant receives heat as it flows through the cooling passage 1180 before exiting via the fluid outlet 1144.

[0084] The e-machine 1000 further includes a channel 2200 fluidically connected to the fluid inlet 1142 such that the channel 2200 may receive fluid coolant from the fluid coolant system via the fluid inlet 1142. The channel 2200 extends circumferentially around the axis 1109. The channel 2000 includes a plurality of fluid outlets 2202 which fluidically connect the channel 2200 to a cavity inside the e-machine housing 1124 within which the stator core 1154 is disposed. Where multiple cooling passages 1180 are present, the fluid outlets 2202 are preferably distributed in a uniform manner about the axis 1109 (i.e., equally spaced about the circumference of the channel 2200) in order to improve the uniformity of flow of fluid coolant through each of the cooling passages 1180. The plurality of fluid outlets 2202 may have substantially the same size and shape as each other.

[0085] By distributing the plurality of fluid outlets 2202 in a uniform manner about the circumference of the channel 2200, the pressure distribution in flooded areas of the stator core may be made more uniform in order to increase the uniformity of temperature of the stator core 1154. In an alternative embodiment, the plurality of fluid outlets 2202 arePATENT APPLICATIONAttorney Docket No. GAR GOO1538 IAarranged in a non-uniform, staggered pattern about the axis 1109. The size and shape of the plurality of fluid outlets 2202 of the channel 2200 may be altered in order to increase the flow rate of fluid coolant out of the plurality of fluid outlets 2202. Additionally, only some of the plurality of fluid outlets 2202 may be altered. For example, a subset of plurality of fluid outlets 2202 may be increased or decreased in size as compared to the remaining plurality of fluid outlets 2202. In this manner, the mass flow rate of fluid coolant may be selectively increased or decreased in various areas in order to selectively increase cooling to “hot-spots” of the stator core 1154. Additionally or alternatively, the angle and position of various fluid outlets 2202 of some or all of the plurality of fluid outlets may be varied to selectively increase cooling to hot-spots of the stator core 1154.

[0086] During operation, fluid coolant is received at the fluid inlet 1142 from the fluid coolant system. Fluid coolant flows from the fluid inlet 1142 to the channel 2200 which extends circumferentially about the axis 1109. Fluid coolant then flows axially out of the fluid outlets 2202 formed in the channel 2200 so as to flood the first axial end 1160 of the stator core 1154 and the end winding 1188 at the first axial end 1160. Fluid coolant then flows through the cooling passages 1180 formed within the stator core 1154. Fluid coolant may then exit the stator core 1154 at the second axial end 1162 of the stator core so as to flood the second axial end 1162 of the stator core 1154 and the end winding 1189 at the second axial end 1162 of the stator core 1154. Fluid coolant may then exit the e-machine via the fluid outlet 1144. Accordingly, the e-machine 1000 may be effectively cooled.Furthermore, the e-machine system 1000 may be compact and lightweight. Also, the part count may be relatively low, and the e-machine system 1000 may be manufactured with high efficiency.

[0087] It will be appreciated that, where fluid coolant floods the first axial end 1160 and the second axial end 1162 of the stator core 1154, adequate sealing of the stator core 1154 is required in order to prevent fluid coolant from entering the slots 1164. In this connection, one or more seals 2250 are provided in order to fluidically isolate the slots 1164 from the fluid coolant.

[0088] The channel 2200 may be provided in the same manner as the channel 200 described above with respect to the direct-slot cooled configuration. In particular, the channel 2200 may be formed from the combination of a groove formed in the bearing housing 1194 and a distributor member (not shown) fixed over the groove, where the distributor member has the plurality of fluid outlets 2202 formed therein. Alternatively, a groove may be formed in thePATENT APPLICATIONAttorney Docket No. GAR GOO1538 IAbearing housing 1194, which groove projects toward the stator core 1154. The groove cooperates with an attached, externally located distributor member (not shown) to form a channel.

[0089] It will also be appreciated that the e-machine may include both of a cooling passage and fluid passageways within windings of the slots so as to provide both indirect and direct slot cooling.

[0090] Lastly, a volume-occupying member (not shown) may be disposed about at least one of the end windings 1188, 1189. The volume-occupying member may be included to reduce the volume of the cavity inside the e-machine housing 1124 that must be flooded by the fluid coolant exiting through the plurality of fluid outlets 2202 of the channel 2200.

[0091] In this document, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Numerical ordinals such as “first,” “second,” “third,” etc. simply denote different singles of a plurality and do not imply any order or sequence unless specifically defined by the claim language. The sequence of the text in any of the claims does not imply that process steps must be performed in a temporal or logical order according to such sequence unless it is specifically defined by the language of the claim. The process steps may be interchanged in any order without departing from the scope of the present disclosure as long as such an interchange does not contradict the claim language and is not logically nonsensical.

[0092] Eurthermore, depending on the context, words such as “connect” or “coupled to” used in describing a relationship between different elements do not imply that a direct physical connection must be made between these elements. For example, two elements may be connected to each other physically, electronically, logically, or in any other manner, through one or more additional elements.

[0093] As used herein, the term “axial” refers to a direction that is generally parallel to or coincident with an axis of rotation, axis of symmetry, or centerline of a component or components. For example, in a cylinder or disc with a centerline and generally circular ends or opposing faces, the “axial” direction may refer to the direction that generally extends in parallel to the centerline between the opposite ends or faces. In certain instances, the term “axial” may be utilized with respect to components that are not cylindrical (or otherwise radially symmetric). For example, the “axial” direction for a rectangular housing containing a rotating shaft may be viewed as a direction that is generally parallel to or coincident with thePATENT APPLICATIONAttorney Docket No. GAR GOO1538 IArotational axis of the shaft. Furthermore, the term “radially” as used herein may refer to a direction or a relationship of components with respect to a line extending outward from a shared centerline, axis, or similar reference, for example in a plane of a cylinder or disc that is perpendicular to the centerline or axis. In certain instances, components may be viewed as “radially” aligned even though one or both of the components may not be cylindrical (or otherwise radially symmetric). Furthermore, the terms “axial” and “radial” (and any derivatives) may encompass directional relationships that are other than precisely aligned with (e.g., oblique to) the true axial and radial dimensions, provided the relationship is predominantly in the respective nominal axial or radial direction. As used herein, the term “substantially” denotes within 5% to account for manufacturing tolerances. Also, as used herein, the term “about” denotes within 5% to account for manufacturing tolerances.

[0094] While at least one exemplary embodiment has been presented in the foregoing detailed description of the present disclosure, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the present disclosure in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing an exemplary embodiment of the present disclosure. It being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope of the present disclosure as set forth in the appended claims.

Claims

PATENT APPLICATIONAttorney Docket No. GAR GOO1538 IACLAIMSWhat is claimed is:

1. An e-machine comprising:a rotor member (118);a stator core (154) having a first axial end (160) and a second axial end (162) that are separated along a longitudinal axis (109), the stator core having a slot (164) that extends between the first axial end and the second axial end;a plurality of winding members, the plurality of winding members comprising a plurality of segments (172) that are received in the slot and that extend between the first axial end and the second axial end, the plurality of segments disposed in an arrangement that define one or more fluid passageways (171) within the slot, the one or more fluid passageways extending between the first axial end and the second axial end of the stator core;a housing (124, 194) at least partially surrounding the stator core and the plurality of winding members, the housing (124, 194) comprising a fluid inlet (142) and a fluid outlet (144);a fluid coolant system configured to provide fluid coolant to the fluid inlet; characterized in that the e-machine comprises a channel (200) at least partially formed by the housing (124, 194), the channel extending circumferentially about the longitudinal axis (109), the channel fluidically connected to the fluid inlet (142) to receive fluid coolant therefrom, wherein the channel comprises a plurality of fluid outlets (202) arranged to allow fluid coolant to flow therethrough so as to flood the stator core with fluid coolant.

2. The e-machine of claim 1, wherein the plurality of fluid outlets (202) are evenly distributed about a circumference of the channel (200).

3. The e-machine of claim 1 or claim 2, wherein the housing comprises an e-machine housing (124) and a bearing housing (194), the e-machine housing and bearing housing configured to together surround the stator core (154) and a bearing upon which the rotor member (118) of the e-machine is supported.PATENT APPLICATIONAttorney Docket No. GAR GOO1538 IA4. The e-machine of claim 3, wherein the channel (200) is formed from a groove in the bearing housing (194) and a distributor member (300) covering the groove, optionally wherein the distributor member is formed from metal or plastic.

5. The e-machine of claim 4, wherein the plurality of fluid outlets (202) are formed in the distributor member (300).

6. The e-machine of claim 4, wherein the plurality of fluid outlets (200) are formed in the groove.

7. The e-machine of claim 3, wherein the channel (200) is formed from a groove in the e-machine housing (124) and a distribution member (300) covering the groove, optionally wherein the distributor member is formed from metal or plastic.

8. The e-machine of claim 7, wherein the plurality of fluid outlets (202) are formed in the distribution member (300).

9. The e-machine of claim 7, wherein the plurality of fluid outlets (200) are formed in the groove.

10. The e-machine of any preceding claim, wherein the stator core (154) comprises a plurality of slots (164), and wherein each one of the plurality of fluid outlets (202) is positioned proximate to a respective one of the plurality of slots (164).

11. The e-machine of any preceding claim, wherein the e-machine is an electric motor.

12. The e-machine of any preceding claim, wherein the e-machine is an electric generator.

13. The e-machine of any preceding claim, further comprising a volume occupying member (400) configured to reduce a volume inside the housing (124, 194).PATENT APPLICATIONAttorney Docket No. GAR GOO1538 IA14. The e-machine of any preceding claim, wherein the plurality of fluid outlets (202) have a circular shape and are aligned either parallel to or at a non-zero angle to the longitudinal axis (109).

15. An e-machine comprising:a rotor member (1118);a stator core (1154) having a first axial end (1160) and a second axial end (1162) that are separated along a longitudinal axis (1109), the stator core having a slot (1164) that extends between the first axial end and the second axial end and a cooling passage (1180) fluidically isolated from the slot (1164);a plurality of winding members, the plurality of winding members comprising a plurality of segments (1172) that are received in the slot (1164) and that extend between the first axial end and the second axial end;a housing (1124, 1194) at least partially surrounding the stator core and the plurality of winding members, the housing (1124, 1194) comprising a fluid inlet (1142) and a fluid outlet (1144);a fluid coolant system configured to provide fluid coolant to the fluid inlet; characterized in that the e-machine comprises a channel (2200) at least partially formed by the housing (1124, 1194), the channel extending circumferentially about the longitudinal axis (1109), the channel fluidically connected to the fluid inlet (1142) to receive fluid coolant therefrom, wherein the channel comprises a plurality of fluid outlets (2202) arranged to allow fluid coolant to flow therethrough so as to flood the stator core with fluid coolant, and wherein the slot (1164) is fluidically isolated from the plurality of fluid outlets (2202) and wherein the cooling passage (1180) is fluidically connected to the plurality of fluid outlets (2202).

16. The e-machine of claim 15, wherein the plurality of fluid outlets (2202) are evenly distributed about a circumference of the channel (2200).

17. The e-machine of claim 15 or claim 16, wherein the housing comprises an e-machine housing (1124) and a bearing housing (1194), the e-machine housing and bearing housingPATENT APPLICATIONAttorney Docket No. GAR GOO1538 IAconfigured to together surround the stator core (1154) and a bearing upon which the rotor member (1118) of the e-machine is supported.

18. The e-machine of claim 17, wherein the channel (2200) is formed from a groove in the bearing housing (1194) and a distributor member (3300) covering the groove, optionally wherein the distributor member is formed from metal or plastic.

19. The e-machine of claim 18, wherein the plurality of fluid outlets (202) are formed in the distributor member (3300) or in the groove.

20. The e-machine of claim 17, wherein the channel (2200) is formed from a groove in the e-machine housing (1124) and a distribution member (3300) covering the groove, optionally wherein the distributor member is formed from metal or plastic.

21. The e-machine of any of claims 15 to 20, wherein the stator core (1154) comprises a plurality of cooling passages (1180), and wherein each one of the plurality of fluid outlets (2202) is positioned proximate to a respective one of the plurality of cooling passages (1180).

22. The e-machine of any of claims 15 to 21, wherein the e-machine is an electric motor.

23. The e-machine of any of claims 15 to 21, wherein the e-machine is an electric generator.

24. The e-machine of any of claims 15 to 23, further comprising a volume occupying member (4400) configured to reduce a volume inside the housing (1124, 1194).

25. The e-machine of any of claims 15 to 24, wherein the plurality of fluid outlets (2202) have a circular shape and are aligned either parallel to or at a non-zero angle to the longitudinal axis (1109).

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