Axle assembly with electric motor module

Abstract

Disclosed is an axle assembly having an electric motor module. The electric motor module may include a rotor, a rotor shaft, a stator, a coolant jacket, an end plate, and a motor housing. The motor housing may surround a portion of the coolant jacket. The end plate may be disposed externally of the motor housing and may not be housed within the motor housing.

Description

Technical Field

[0001] The present disclosure relates to an axle assembly having an electric motor module and a method of assembling the same. background

[0002] An axle assembly with an electric motor module is disclosed in U.S. Patent Publication No. 2019 / 0054816.

[0003] Overview

[0004] In at least one embodiment, an axle assembly is provided. The axle assembly may include an electric motor module. The electric motor module may include a rotor, a rotor shaft, a stator, a coolant jacket, an end plate, and a motor housing. The rotor may be rotatable about a rotor axis. The rotor shaft may extend from the rotor and may be rotatable together with the rotor about the rotor axis. The stator may surround the rotor. The coolant jacket may surround the stator and may have a set of channels that may open in a direction away from the rotor axis. The end plate may engage and be fixedly attached to an end of the coolant jacket and may support the rotor shaft. The motor housing may surround a portion of the coolant jacket. The motor housing may be spaced apart from the end plate. The end plate may not be housed within the motor housing. The coolant jacket may not be housed within the end plate. Several channels in the set of channels may be housed within the motor housing. The remaining channels in the set of channels may not be housed within the motor housing.

[0005] In at least one embodiment, a method of manufacturing an axle assembly is provided. The method may include assembling an electric motor module by partially inserting a coolant jacket, a stator, a rotor, and a rotor shaft into a motor housing. The stator may surround the rotor. The coolant jacket may surround the stator. The coolant jacket may have a set of channels arranged around the stator. An end plate may be attached to the end of the coolant jacket disposed outside the motor housing such that the rotor shaft extends through and is supported by the end plate. The electric motor module may then be mounted on the transmission housing assembly by inserting a portion of the coolant jacket that is not partially contained within the motor housing into the transmission housing assembly. The motor housing may be secured to the transmission housing assembly such that the end plate is fully contained within the transmission housing assembly, a plurality of channels in the set of channels are contained within the motor housing, and the remaining channels in the set of channels are contained within the transmission housing assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 is a perspective view of an example of a driven axle system.

[0007] Figure 2 is a cross-sectional view of the drive axle system along section line 2-2.

[0008] Figure 3 is a cross-sectional view of the drive axle system along section line 3-3.

[0009] Figure 4 yes Figure 3 An enlarged view of a portion of the driven axle system is shown.

[0010] Figure 5-8 An exploded view of a portion of the driven axle system. DETAILED DESCRIPTION

[0011] As required, detailed embodiments of the present invention are disclosed herein; however, it should be understood that the disclosed embodiments are merely examples of the invention that may be embodied in various and alternative forms. The drawings are not necessarily to scale; some features may be exaggerated or minimized to illustrate details of particular components. Therefore, the specific structural and functional details disclosed herein should not be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention.

[0012] refer to Figure 1 , shows an example of a drive axle system 10. The drive axle system 10 may be provided with a vehicle, such as a passenger car, automobile, truck, etc. In at least one configuration, the drive axle system 10 may include a support structure 20, a suspension system 22, and one or more axle assemblies 24.

[0013] The support structure 20 can be configured to support a pair of axle assemblies 24. Furthermore, the support structure 20 can operatively connect the axle assemblies 24 to the suspension system 22. In at least one configuration, the support structure 20 can include a main support 30 and a plurality of arms 32.

[0014] The main support 30 can support multiple axle assemblies 24. For example, the main support 30 can extend in a lateral direction, or in a direction extending from the left side of the vehicle to the right side of the vehicle. The axle assemblies 24 can be disposed near each lateral end of the main support 30 (i.e., at opposite ends of the main support 30). In at least one configuration, the main support 30 can extend below each axle assembly 24 and can have a generally flat or planar top surface 34.

[0015] refer to Figure 1 and Figure 2, the top surface 34 can be disposed between the axle assemblies 24 and can be positioned below the wheel axis of rotation or wheel axis 40. This configuration can provide a gap between the axle assemblies 24 through which a portion of the vehicle's body structure 50 can extend. More specifically, a portion of the body structure 50 defining a floor or gangway 52 of the vehicle can be located between the axle assemblies 24, thereby positioning the floor or gangway 52 closer to the ground or road on which the vehicle is located. The floor or gangway 52 can extend in a longitudinal direction through the gap between the axle assemblies 24 such that the bottom of the floor or gangway 52 can be positioned below the top of the axle assemblies 24 and below the wheel axis 40. In a vehicle such as a passenger car, the gangway 52 can be a passenger gangway. For clarity, the gangway 52 is shown in FIG. Figure 1 The vehicle body structure is shown in phantom without the vehicle body structure to more clearly illustrate the other components of the drive axle system 10 .

[0016] refer to Figure 2 The body structure 50 defining a floor or tunnel 52 may extend above the top surface 34 and may be spaced apart from the top surface to accommodate body roll or tilt of the body structure 50 in a lateral direction, such as may occur when the vehicle turns a corner. The extent of body roll is determined by Figures 2 to 4 , and can be any suitable amount, such as ±5°.

[0017] refer to Figure 1 , one or more arms 32 can extend from the main support member 30. The arms 32 can be disposed near the ends of the main support member 30 and can generally extend in a longitudinal direction (e.g., a forward or rearward direction that can be perpendicular to the lateral direction). In the illustrated configuration, four arms 32 are depicted and are arranged such that a pair of arms 32 is disposed near each lateral end of the main support member 30. One arm 32 in the pair can extend in a vehicle-forward direction, while the other arm 32 can extend in a vehicle-rearward direction.

[0018] The suspension system 22 can connect the support structure 20 to the frame or chassis of the vehicle. In addition, the suspension system 22 can suppress vibrations associated with vehicle travel, provide a desired level of ride quality, help control the vehicle's ride height, or a combination thereof. The suspension system 22 can have any suitable configuration. For example, the suspension system 22 can be an independent suspension system, which can allow the wheels to move up and down independently of each other or without being affected by one another. Alternatively, the suspension system 22 may not be an independent suspension system. The suspension system 22 can include one or more dampers 36, such as air springs, shock absorbers, or a combination thereof. In the illustrated configuration, the dampers 36 are depicted as air springs, and the dampers 36 are disposed near the distal end of each arm 32 of the support structure 20. The top side of each air spring can be disposed beneath the chassis of the vehicle and can support the chassis.

[0019] refer to Figure 1 and Figure 2 , the axle assembly 24 can provide torque to the traction wheel assembly. In at least one configuration and as Figure 2 As best shown in FIG, the axle assembly 24 may include a wheel end assembly 60 , a transmission housing assembly 62 , a transmission 64 , and an electric motor module 66 .

[0020] The wheel end assembly 60 can be disposed at the outboard end of the axle assembly 24. For example, the wheel end assembly 60 can be disposed at the outboard end of the axle assembly 24, away from the floor or aisle 52 and opposite the electric motor module 66. The wheel end assembly 60 can facilitate mounting of a wheel 70, on which a tire can be mounted. For example, the wheel end assembly 60 can include a hub 72 that can be rotatable about the wheel axis 40. The hub 72 can include a plurality of lug bolts that can extend through corresponding holes in the wheel 70 in a manner known to those skilled in the art. Optionally, a reduction gear can be provided with the wheel end assembly 60. For example, a reduction gear set having a bevel gear or a planetary gear set can be provided with the wheel end assembly 60 to provide a gear reduction between the transmission 64 and the wheel hub 72. In at least one configuration, the wheel end assembly 60 can include a wheel end shaft 74 that can be operatively connected to the wheel hub 72 and the transmission 64. For example, torque can be transmitted between the transmission 64 and the wheel end assembly 60 via the wheel end shaft 74.

[0021] The transmission housing assembly 62 can support the wheel end assembly 60 and can house the transmission 64. In addition, the transmission housing assembly 62 can house a portion of the electric motor module 66, as will be discussed in more detail below. The transmission housing assembly 62 can be positioned axially between the wheel end assembly 60 and the electric motor module 66. In at least one configuration, the transmission housing assembly 62 can include an outer transmission housing 80 and an inner transmission housing 82.

[0022] refer to Figure 2 、 Figure 6 and Figure 8 , the outer transmission housing 80 can support the wheel end assembly 60. For example, the wheel end assembly 60 can be mounted to the outer transmission housing 80. The outer transmission housing 80 can be positioned axially between the wheel end assembly 60 and the inner transmission housing 82. The outer transmission housing 80 or a portion thereof can be located inside the wheel 70. In at least one configuration, the outer transmission housing 80 can include an outer end wall 90 and a flange wall 92.

[0023] The outboard end wall 90 may extend in a generally vertical direction. The outboard end wall 90 may be positioned inwardly of the wheel 70 and may be spaced apart from the inboard transmission housing 82. The outboard end wall 90 may define an output shaft bore 100 and a bearing recess 102.

[0024] exist Figure 6 and Figure 8 The output shaft hole 100 best shown in FIG. 1 may be a through hole that may be disposed along and extend around the wheel axis 40 . The wheel end shaft 74 may extend through the output shaft hole 100 .

[0025] refer to Figure 3 and Figure 6 , a bearing recess 102 can be provided on a side of the outboard end wall 90 that can face the inboard transmission housing 82. The bearing recess 102 can be configured to accommodate and support a rotor bearing 110 that can rotatably support the rotor shaft, as will be discussed in greater detail below. The bearing recess 102 can be provided along a rotor axis 120 and can be centered about the rotor axis.

[0026] refer to Figure 1 and Figure 3 , the rotor axis 120 can be disposed parallel or substantially parallel to the wheel axis 40. In at least one configuration, the rotor axis 120 can be positioned below the wheel axis 40 or closer to the ground than the wheel axis 40. In the configuration shown, the wheel axis 40 is not positioned directly above the rotor axis 120; however, it is contemplated that in one or more configurations, the wheel axis 40 can be disposed directly above the rotor axis 120.

[0027] refer to Figure 2 、 Figure 6 and Figure 8 The flange wall 92 may extend from the outer end wall 90 toward the inner transmission housing 82. For example, the flange wall 92 may be configured as a ring that may extend around or encircle the wheel axis 40 and the rotor axis 120 and may extend from the outer end wall 90 to the inner transmission housing 82. Figure 2 As best shown in FIG, the flange wall 92 or a portion thereof can be housed within the interior of the wheel 70. In at least one configuration, a portion of the flange wall 92 can extend generally parallel to the wheel axis 40, the rotor axis 120, or both. Figure 6 and Figure 8 As best shown in FIG, the flange wall 92 may include one or more outwardly extending flanges that may facilitate mounting the outer transmission case 80 to the inner transmission case 82. For example, fastener holes 130 may be provided that may receive corresponding fasteners 132 (e.g., bolts) that may couple the outer transmission case 80 to the inner transmission case 82. For clarity, only some of the fastener holes 130 and fasteners 132 are labeled in these figures.

[0028] refer to Figure 2 、 Figure 6 and Figure 8 , the inner transmission housing 82 can support the outer transmission housing 80. For example, the outer transmission housing 80 can be mounted to the inner transmission housing 82. The inner transmission housing 82 can be positioned axially between the outer transmission housing 80 and the electric motor module 66. The inner transmission housing 82 and the outer transmission housing 80 can cooperate to define a transmission housing cavity 140 (at Figure 3 ), the transmission housing cavity can house the transmission 64. In at least one configuration, the inner transmission housing 82 can include a divider wall 142, a first outer wall 144, and a second outer wall 146.

[0029] refer to Figure 2 , the partition wall 142 can be positioned between the transmission 64 and the electric motor module 66. In addition, the partition wall 142 can be positioned axially between the first outer wall 144 and the second outer wall 146, as shown in FIG. Figure 4 . For example, the divider wall 142 may extend from the end of the first outer wall 144 and the end of the second outer wall 146 inwardly toward the wheel axis 40 and the rotor axis 120. The divider wall 142 may extend in a generally vertical direction. Thus, the divider wall 142 or a portion thereof may be disposed substantially parallel to the outboard end wall 90 of the outboard transmission case 80. In one or more embodiments, the divider wall 142 may be taller or have a greater height than the outboard end wall 90 and may not be housed within the wheel 70. In at least one configuration and as Figure 6 and Figure 8 As best shown in FIG, the divider wall 142 may define a rotor shaft bore 150 and a bearing recess 152 .

[0030] The rotor shaft hole 150 may be a through hole that may be disposed along the rotor axis 120 and may extend around the rotor axis. The rotor shaft hole 150 may accommodate the second rotor bearing 110' (at Figure 3 ), the second rotor bearing can rotatably support the rotor shaft, as will be discussed in more detail below.

[0031] refer to Figure 2 and Figure 8 , a bearing recess 152 can be provided on a side of the divider wall 142 that can face the outer transmission housing 80. For example, the bearing recess 152 can extend from a side of the divider wall 142 that can face the transmission 64 and away from the electric motor module 66. The bearing recess 152 can be configured to accommodate and support a bearing 154 that can directly or indirectly rotatably support the wheel end shaft 74. The bearing recess 152 can be provided along the wheel axis 40 and can be centered about the wheel axis.

[0032] Main references Figure 3 、 Figure 4 、 Figure 6 and Figure 8 , the first outer wall 144 can extend from the partition wall 142 in a direction extending toward the electric motor module 66. For example, the first outer wall 144 can be configured as a ring that can extend around or encircle the wheel axis 40 and the rotor axis 120 and can extend from the partition wall 142 to the electric motor module 66. In addition, the first outer wall 144 can extend around or encircle multiple components of the electric motor module 66, as will be discussed in more detail below. In at least one configuration and as Figure 6 As best shown in FIG. 1 , the first outer wall 144 may define a port 160 .

[0033] The port 160 may be a through hole that may extend through the first outer wall 144 and may receive a fitting 162. The port 160 may be fluidly connected to a coolant jacket of the electric motor module 66, as will be discussed in greater detail below.

[0034] Main references Figure 3 、 Figure 6 and Figure 8, the second outer wall 146 can extend from the partition wall 142 in a direction extending toward the outer transmission housing 80. For example, the second outer wall 146 can be configured as a ring that can extend around or encircle the wheel axis 40 and the rotor axis 120 and can extend from the partition wall 142 to the flange wall 92 of the outer transmission housing 80. The second outer wall 146 can extend around or encircle components of the transmission 64. For example, the second outer wall 146 can partially encircle the gears of the transmission 64 and can be partially accommodated inside the wheel 70. Figure 8 As best shown in FIG, second outer wall 146 may have a plurality of fastener holes 170 that may receive corresponding fasteners 132 that may couple outer transmission case 80 to inner transmission case 82. First outer wall 144 and second outer wall 146 may extend from divider wall 142 in opposite directions.

[0035] refer to Figure 2 and Figure 3 The transmission 64 can transmit torque between the wheel end assembly 60 and the electric motor module 66. The transmission 64 can be housed within the transmission housing cavity 140 of the transmission housing assembly 62. Thus, the transmission 64 can be axially positioned between the outer end wall 90 of the outer transmission housing 80 and the dividing wall 142 of the inner transmission housing 82, and can be surrounded by the flange wall 92 of the outer transmission housing 80 and the second outer wall 146 of the inner transmission housing 82. The transmission 64 can include a plurality of gears that can transmit torque between the electric motor module 66 and the wheel end assembly 60. In at least one embodiment, the transmission 64 can include an upper gear 180 and a lower gear 182.

[0036] The upper gear 180 may be rotatable with the wheel end shaft 74 about the wheel axis 40. The upper gear 180 may have teeth that may extend away from the wheel axis 40 and may mate or mesh with teeth of the lower gear 182. The upper gear 180 may be rotatably supported directly or indirectly by a bearing 154 that is received in a bearing recess 152 of the inner transmission case 82.

[0037] The lower gear 182 may be rotatable with the rotor shaft about the rotor axis 120 , as will be discussed in greater detail below. The lower gear 182 may have a plurality of teeth that may extend away from the rotor axis 120 .

[0038] refer to Figure 1 and Figure 2, the electric motor module 66 can provide torque to the wheel end assembly 60 to help propel the vehicle. In addition, the electric motor module 66 can receive torque from the wheel end assembly 60 to help recover energy or provide regenerative braking. The electric motor module 66 can be electrically connected to a power source, such as a battery, capacitor, etc. The inverter can electrically connect the electric motor module 66 and the power source in a manner known to those skilled in the art. The electric motor module 66 can have any suitable configuration. In at least one configuration and as described in reference Figure 4 As best shown, the electric motor module 66 may include a motor housing 200, a coolant jacket 202, a stator 204, a rotor 206, and a rotor shaft 208. The electric motor module 66 may also include an end plate 210 and a cover 212.

[0039] refer to Figure 4 、 Figure 5 and Figure 7 The motor housing 200 can be disposed at an end of the axle assembly 24 opposite the wheel end assembly 60. Thus, the motor housing 200 can be positioned axially between the vehicle body structure 50 defining the floor or tunnel 52 and the transmission housing assembly 62. In at least one configuration, the motor housing 200 can include an end wall 220 and an exterior wall 222. The motor housing 200 can also at least partially define a junction box 224.

[0040] An end wall 220 can be positioned at an end of the motor housing 200 that can face the passageway 52. ​​For example, the end wall 220 can be positioned axially between the cover 212 and components such as the coolant jacket 202, the stator 204, the rotor 206, and the rotor shaft 208. The end wall 220 can extend from an end of the exterior wall 222 toward the rotor axis 120. The end wall 220 can extend in a generally vertical direction. Thus, the end wall 220 can be disposed generally parallel to the end plate 210. In at least one configuration, the end wall 220 can define a central aperture 230.

[0041] The central hole 230 may be a through hole that may be disposed along the rotor axis 120 and may extend around the rotor axis. The central hole 230 may receive a rotor bearing 110 ″ that may rotatably support the rotor shaft 208 .

[0042] The outer wall 222 can extend from the end wall 220 in a direction extending toward the transmission housing assembly 62. For example, the outer wall 222 can be configured as a ring that can extend around or encircle the wheel axis 40 and the rotor axis 120 and can extend from the end wall 220 to the first outer wall 144 of the inner transmission housing 82. Thus, the end of the outer wall 222 can abut the end of the first outer wall 144. In addition, the outer wall 222 can extend around or encircle a portion of the components of the electric motor module 66, such as the coolant jacket 202, the stator 204, and the rotor 206. The inner side of the outer wall 222 facing the rotor axis 120 can surround and engage the coolant jacket 202.

[0043] The outer wall 222 can extend axially, or in an axial direction extending along the rotor axis 120 toward the inner transmission case 82, such that the coolant jacket 202, the stator 204, and the rotor 206 are partially contained within the outer wall 222, and such that the coolant jacket 202, the stator 204, and the rotor 206 protrude in an outboard direction from an end of the outer wall 222 that engages an end of the first outer wall 144. Conversely, the first outer wall 144 can extend axially, or in a direction extending along the rotor axis 120 toward the outer wall 222, such that the coolant jacket 202, the stator 204, and the rotor 206 are partially contained within the first outer wall 144. In at least one configuration, the outer wall 222 and the first outer wall 144 can meet near the center of the coolant jacket 202.

[0044] In at least one configuration and as referenced Figure 5 As best shown, the exterior wall 222 may define a port 240 .

[0045] The port 240 may be a through hole that may extend through the outer wall 222 and may accommodate the fitting 162. The port 240 may be fluidly connected to the coolant jacket 202, as discussed in greater detail below. The port 240 may be spaced or separated from the port 160 provided with the inner transmission case 82.

[0046] A junction box 224, which may also be referred to as a terminal box, may extend from end wall 220, exterior wall 222, or both. Junction box 224 may house wiring or electrical connectors that may be associated with components such as stator 204, a rotary transformer 226 that may detect rotation of rotor 206, and the like. Junction box 224 may have a low profile and may not protrude axially beyond the end of cover 212 to help provide clearance for vehicle body structure 50.

[0047] refer to Figure 4 、 Figure 5 and Figure 7The coolant jacket 202 can help cool the stator 204 or remove heat from the stator. The coolant jacket 202 can extend around the rotor axis 120 and can not rotate about the rotor axis 120. Furthermore, the coolant jacket 202 can be fixedly positioned relative to the motor housing 200. The coolant jacket 202 can be partially housed within the motor housing 200. For example, a portion of the coolant jacket 202, facing away from the rotor axis 120, can engage or contact the inside of the motor housing 200. Furthermore, when the electric motor module 66 is mounted to the transmission housing assembly 62, the coolant jacket 202 can be partially housed within the inner transmission housing 82. For example, a portion of the coolant jacket 202, facing away from the rotor axis 120, can engage or contact the inside of the first outer wall 144, which can face the rotor axis 120. The coolant jacket 202 can extend axially between the end wall 220 and the end plate 210 of the motor housing 200. In at least one configuration, the coolant jacket 202 can include a set of channels 250.

[0048] The passage 250 can extend around the rotor axis 120 and can be positioned opposite the stator 204. For example, the passage 250 can extend from the outside of the coolant jacket toward the stator 204. The passage 250 can be configured to have an open side that can be away from the rotor axis 120 and face the inside of the motor housing 200. Thus, the passage 250 can be open in a direction away from the rotor axis 120. Coolant can be supplied to and removed from the passage 250 via ports 160, 240. For example, coolant can enter the passage 250 via port 240 in the motor housing 200 and can exit the passage 250 via port 160 in the inner transmission housing 82, or vice versa. Thus, coolant can enter the passage 250 via one port, receive heat from the stator 204 as it flows through the passage 250, and exit the passage 250 via another port. One or more baffles may be provided with the coolant jacket 202 that may reverse or change the direction of coolant flow to help transfer coolant between the ports 160, 240. For clarity, Figure 4 、 Figure 5 and Figure 7 Only some of the channels 250 are labeled.

[0049] Some of the channels in the set of channels 250 may be housed within and surrounded by the exterior wall 222 of the motor housing 200, while other channels in the set of channels 250 may be housed within and surrounded by the first exterior wall 144 of the inner transmission housing 82. For example, some, but not all, of the channels in the set of channels 250 may be housed within and surrounded by the exterior wall 222, while the remaining channels in the set of channels 250 may be housed within and surrounded by the first exterior wall 144. Channels 250 surrounded by the exterior wall 222 may not be surrounded by the first exterior wall 144. Conversely, channels 250 surrounded by the first exterior wall 144 may not be surrounded by the exterior wall 222.

[0050] refer to Figure 4 、 Figure 5 and Figure 7 , the stator 204 can be housed within the coolant jacket 202. Furthermore, the stator 204 can be fixedly positioned relative to the coolant jacket 202. Thus, the stator 204 can be fixedly positioned relative to the motor housing 200. The stator 204 can extend about the rotor axis 120 and can not rotate about the rotor axis 120. Furthermore, the stator 204 can have an axial length similar to that of the coolant jacket 202. The stator 204 can include stator windings that can be housed within the coolant jacket 202 and can be fixedly positioned relative to the coolant jacket. The windings can be electrically connected to a power source. The stator 204 can surround the rotor 206.

[0051] The rotor 206 may be housed within the coolant jacket 202 and the stator 204. Furthermore, the rotor 206 may extend about the rotor axis 120 and may be rotatable about the rotor axis. The rotor 206 may be rotatable about the rotor axis 120 relative to the stator 204. The rotor 206 may be spaced apart from the stator 204, but may be positioned proximate to the stator 204. The rotor 206 may include magnets or ferromagnetic materials that may facilitate current generation or may be induction-based. The rotor 206 may extend about a rotor shaft 208 and may be supported by the rotor shaft.

[0052] The rotor shaft 208 can be fixedly mounted to the rotor 206. Thus, the rotor 206 and the rotor shaft 208 can rotate together about the rotor axis 120 and can not rotate relative to each other. In at least one configuration, the rotor shaft 208 can be housed within the rotor 206. The rotor shaft 208 can extend along or about the rotor axis 120 and can have a one-piece construction or a multi-piece construction. The rotor shaft 208 can operably connect the rotor 206 to the transmission 64.

[0053] refer to Figure 4 、 Figure 5 and Figure 7 The end plate 210 can be positioned at an end of the electric motor module 66's divider wall 142 disposed outside the electric motor housing 200 and facing the inner transmission housing 82. Thus, the end plate 210 can be separated or spaced apart from the motor housing 200. The end plate 210 can be positioned adjacent to the divider wall 142 and can be positioned axially between the divider wall 142 and components of the electric motor module 66, such as the coolant jacket 202, the stator 204, and the rotor 206. The end plate 210 can be secured to the coolant jacket 202 in any suitable manner. For example, the end plate 210 can be attached to the end of the coolant jacket 202 disposed outside the motor housing 200 using a plurality of fasteners 260, such as bolts. Thus, the end plate 210 can engage the coolant jacket 202 and cannot rotate about the rotor axis 120. In at least one configuration, the end plate 210 can be configured as a generally circular disk that can be received within the interior of the first outer wall 144 of the inner transmission housing 82. Thus, the end plate 210 can have a smaller diameter than the first outer wall 144. The end plate 210 can define a central bore 270.

[0054] The central hole 270 may be a through hole that may be disposed along the rotor axis 120 and may extend around the rotor axis. The central hole 270 may accommodate the rotor bearing 110'. For example, the rotor bearing 110' may be partially accommodated within the rotor shaft hole 150 of the partition wall 142 and may be partially accommodated within the central hole 270. The central hole 270 may be partially formed by the end plate 210 and may extend axially toward the rotor 206 or from the end plate 210. Figure 4 The angle shown is defined by a portion extending to the left. Thus, a portion of the end plate 210 may be received within the coolant jacket 202.

[0055] refer to Figures 2 to 4, the rotor shaft 208 may be supported by the transmission housing assembly 62, the motor housing 200, the end plate 210, or a combination thereof. For example, the rotor shaft 208 may be supported by the rotor bearing 110 disposed on the outer transmission housing 80, the rotor bearing 110' which may be supported by the divider wall 142 and the end plate 210, and the rotor bearing 110" which may be supported by the end wall 220 of the motor housing 200. The rotor shaft 208 may be housed within each of the rotor bearings 110, 110', 110". The rotor bearings 110 , 110 ′, 110 ″ may be spaced apart from one another and may be arranged such that rotor bearing 110 is disposed at a first end of rotor shaft 208 , rotor bearing 110 ″ is disposed at an opposite end of rotor shaft 208 , and rotor bearing 110 ′ is positioned between the other two rotor bearings 110 , 110 ″ along rotor axis 120 such that rotor shaft 208 extends through rotor bearing 110 ′ and the rotor shaft aperture 150 of inner transmission housing 82 and the central aperture 270 of end plate 210 .

[0056] refer to Figure 4 and Figure 5 The cover 212 can extend over the central aperture 230 in the end wall 220 and can cover or conceal the central aperture. For example, the cover 212 can be mounted to a side of the end wall 220 that faces the vehicle body structure defining the floor or tunnel 52. The rotor shaft 208 can extend through the central aperture 230 such that the rotor shaft 208 is partially contained within the cover 212. In at least one configuration, the cover 212 can have a tapered portion 280.

[0057] Main references Figure 4 The tapered portion 280 may extend about the rotor axis 120 or may wrap around the rotor axis. The tapered portion 280 may taper away from the rotor axis 120 such that the tapered portion 280 progressively moves closer to the end wall 220 as the distance from the rotor axis 120 increases. Tapering in this manner may help provide body roll clearance between the electric motor module 66 and the body structure 50 defining the floor or tunnel 52.

[0058] The electric motor module 66 as described above can allow the electric motor to be pre-assembled, adjusted, and tested prior to installation or assembly with the rest of the axle assembly 24. For example, the coolant jacket 202 and the stator 204 can be secured to each other and can be inserted and secured to the motor housing 200 such that the coolant jacket 202 and the stator 204 protrude from the motor housing 200. The rotary transformer 226, the rotor 206, and the rotor shaft 208 can be inserted into the cavity defined by the stator 204 and can be supported by the rotor bearing 110", which can be received in the central bore 230 of the end wall 220. The end plate 210 can then be fastened to the end of the coolant jacket 202 that protrudes from the motor housing 200 such that the rotor shaft 208 can be supported by the rotor bearing 110', which can be received in the central bore 270 of the end plate 210.

[0059] The axle assembly described above can help position the vehicle's aisle closer to the ground by positioning the wheel axis above the rotor axis, which may be desirable on vehicles such as low-floor buses. Furthermore, the axle assembly described above can help increase the width of the aisle by reducing the axial length of the axle assembly, which can increase the lateral distance available between axle assemblies disposed on a common support structure. Providing an electric motor module that is only partially contained within another housing (such as an inner transmission housing) can facilitate cost and weight reduction and increase available packaging space, compared to providing an electric motor with components (such as a coolant jacket, stator, and rotor) completely enclosed within the motor housing. Furthermore, enclosing the motor within another housing assembly can reduce or limit the size or diameter of the electric motor that can be provided, which in turn can reduce or limit the performance of the electric motor. Providing an electric motor module that is only partially contained within another housing assembly can improve accessibility to internal components for servicing, simplify assembly, and facilitate reducing associated costs. Partially enclosing the coolant jacket in a different housing so that the coolant jacket and its passages are not completely contained within one housing can facilitate reducing the width and weight of the transmission housing and can make it easier to position and package the junction box in a manner that does not reduce or interfere with the width of the aisle.

[0060] While exemplary embodiments have been described above, these embodiments are not intended to describe all possible forms of the present invention. Rather, the terms used in this specification are illustrative rather than restrictive, and it should be understood that various changes may be made without departing from the spirit and scope of the present invention. Furthermore, the features of various implemented embodiments may be combined to form additional embodiments of the present invention.

Claims

1. An axle assembly comprising: An electric motor module, the electric motor module comprising: a rotor rotatable about a rotor axis; a rotor shaft extending from the rotor and rotatable with the rotor about the rotor axis; a stator surrounding the rotor; a coolant jacket surrounding the stator and having a set of passages opening in a direction away from the rotor axis; an end plate engaging and fixedly attached to an end of the coolant jacket, wherein the end plate supports the rotor shaft; and a motor housing surrounding a portion of the coolant jacket, wherein the motor housing is spaced apart from the end plate, the end plate not being received within the motor housing, and wherein the end plate does not surround the coolant jacket; Wherein, a plurality of channels in the set of channels are accommodated inside the motor housing, and the remaining channels in the set of channels are not accommodated inside the motor housing.

2. The axle assembly of claim 1, wherein: The motor housing includes an outer wall surrounding and engaging the coolant jacket, and an end wall extending from an end of the outer wall toward the rotor axis, the end wall defining a central bore extending about the rotor axis, wherein the rotor shaft is rotatably supported by a first rotor bearing received within the central bore of the end wall.

3. The axle assembly of claim 2, wherein: A cover is mounted to the end wall of the motor housing and extends over and closes the central aperture of the end wall.

4. The axle assembly of claim 3, wherein: The rotor shaft extends through the central aperture of the end wall such that the rotor shaft is partially contained within the cover.

5. The axle assembly of claim 3, wherein: The cover has a tapered portion that surrounds and tapers away from the rotor axis such that the tapered portion progressively approaches the end wall with increasing distance from the rotor axis to provide body roll clearance for a body structure defining the tunnel.

6. The axle assembly of claim 1 , further comprising: a wheel end assembly rotatable about a wheel axis disposed above the rotor axis, wherein the wheel end assembly includes a hub adapted to facilitate mounting of a wheel; and An inner transmission housing having: a first outer wall adjacent to the motor housing and extending around and partially accommodating the coolant jacket, the stator, and the rotor; a partition wall extending from an end of the first outer wall toward the rotor axis; and a second outer wall extending from the partition wall in an axial direction extending away from the first outer wall, wherein the first outer wall and the second outer wall extend around the rotor axis and the wheel axis.

7. The axle assembly of claim 6, wherein: The inboard transmission housing is positioned along the wheel axis between the motor housing and the wheel end assembly.

8. The axle assembly of claim 6, wherein: The motor housing defines a first port in fluid connection with the coolant jacket, and the inner transmission housing defines a second port separate from the first port and in fluid connection with the coolant jacket.

9. The axle assembly of claim 6, further comprising a transmission that transmits torque between the electric motor module and the wheel end assembly, wherein The transmission is housed inside the inner transmission housing.

10. The axle assembly of claim 9, wherein: The transmission is partially surrounded by the second outer wall.

11. The axle assembly of claim 9, wherein: The second outer wall is partially received within an interior of a wheel mounted to the wheel end assembly.

12. The axle assembly of claim 9, wherein: The divider wall is positioned between the electric motor module and the transmission.

13. The axle assembly of claim 9, wherein: The first outer wall surrounds remaining channels of the set of channels that are not contained within the motor housing.

14. The axle assembly of claim 6, wherein: The end plate is positioned axially between the dividing wall and the rotor, the stator, and the coolant jacket.

15. The axle assembly of claim 6, wherein: The end plate is housed entirely within the inner transmission case and / or partially within the coolant jacket.

16. The axle assembly of claim 6, wherein: The rotor shaft is rotatably supported by a second rotor bearing extending from the partition wall and the end plate.

17. The axle assembly of claim 16, wherein: The second rotor bearing is accommodated inside the rotor shaft hole of the partition wall and inside the central hole of the end plate.

18. The axle assembly of claim 9, wherein: The partition wall has a recessed portion that is arranged along the wheel axis and extends from a side of the partition wall facing the transmission, wherein the recessed portion accommodates a bearing that rotatably supports an upper gear of the transmission that is rotatable about the wheel axis.

19. The axle assembly of claim 18, wherein: The transmission includes a lower gear meshing with the upper gear, mounted to the rotor shaft, and rotatable about the rotor axis.

20. A method of manufacturing an axle assembly, comprising: Assemble the electric motor module using the following steps: partially inserting a coolant jacket, a stator, a rotor, and a rotor shaft into an interior of a motor housing, wherein the stator surrounds the rotor, the coolant jacket surrounds the stator, and the coolant jacket has a set of channels disposed around the stator; attaching an end plate to an end of the coolant jacket disposed outside the motor housing such that the rotor shaft extends through and is supported by the end plate; mounting the electric motor module on the transmission housing assembly by inserting the portion of the coolant jacket not partially contained within the motor housing into the transmission housing assembly; and The motor housing is secured to the transmission housing assembly, wherein the end plate is completely contained within the transmission housing assembly, a plurality of passages in the set of passages are contained within the motor housing, and the remaining passages in the set of passages are contained within the transmission housing assembly.

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