Electric vehicle drive module cooling

Abstract

A drive module is employed for use in a hybrid electric vehicle (HEV) powertrain or for use in a battery electric vehicle (BEV) powertrain. The drive module is used to propel movement of an accompanying hybrid electric vehicle or battery electric vehicle. In implementations, the drive module includes a housing, an electric motor, a gear assembly, a coolant reservoir, and a coolant passage. The electric motor has a stator and a rotor. The rotor has a shaft. The gear assembly has its movement driven by the shaft. The coolant passage is in a wall of the housing. During use, coolant is drawn from the coolant reservoir through the coolant passage.

Description

Technical Field

[0001] This application relates to drive modules equipped in hybrid electric vehicle (HEV) power systems and battery electric vehicle (BEV) power systems, and more particularly, to cooling measures employed in such drive modules. Background Technology

[0002] Hybrid electric vehicles and battery electric vehicles in the automotive industry are typically equipped with drive modules to drive their wheels and for vehicle propulsion. Depending on the larger powertrain architecture, a drive module typically includes an electric motor and a reduction gear and / or differential assembly, and may further include cooling and lubrication systems. An electric motor typically has a rotor and a stator. The rotor is caused to rotate while the stator remains stationary relative to the rotor. In these arrangements, the rotation of the rotor typically drives the rotation of the drive shaft. Significant heat is typically generated at the electric motor. The cooling system distributes coolant within the components of the electric motor to dissipate this heat. Summary of the Invention

[0003] In one implementation, the electric vehicle drive module may include a housing, an electric motor, a gear assembly, a coolant reservoir, and a coolant passage. The electric motor is located within the housing. The electric motor has a stator and a rotor. The rotor has a shaft. The gear assembly is driven to rotate by the rotor's shaft. The coolant reservoir is constructed within the housing. The coolant passage is located within the walls of the housing. The coolant passage is in fluid communication with the rotor's shaft and with the coolant reservoir. During use of the electric vehicle drive module, coolant is drawn from the coolant reservoir and passes through the coolant passage.

[0004] In another implementation, a method for providing coolant in an electric motor of an electric vehicle drive module may include several steps. One step involves providing a first volumetric flow rate of coolant to the electric motor via a pump. The pump operates to pump coolant from a coolant reservoir of the electric vehicle drive module and into a coolant circuit of the electric motor. Another step involves drawing coolant from the coolant reservoir through a coolant passage via rotation of the rotor shaft of the electric motor. The coolant passage is in fluid communication with the coolant circuit. Yet another step involves providing a second volumetric flow rate of coolant to the coolant circuit via a pump. The second volumetric flow rate is provided after the coolant has been drawn from the coolant reservoir through the coolant passage via rotation of the rotor shaft of the electric motor. The second volumetric flow rate of the coolant is less than the first volumetric flow rate of the coolant.

[0005] In another implementation, the electric vehicle drive module may include a housing, an electric motor, a gear assembly, a coolant reservoir, a coolant passage, a lower pressure region, and a pump. The housing has an inner wall, end walls, or both. The electric motor is located within the housing and has a stator and a rotor. The rotor has a shaft. The gear assembly is rotatably driven by the rotor shaft. The coolant reservoir is established within the housing. The coolant passage is located within the inner wall, end walls, or both. The coolant passage is in fluid communication with the coolant reservoir and with the coolant circuit of the electric motor. The lower pressure region is adjacent to the shaft. The lower pressure region is in fluid communication with the coolant passage. The pump is in fluid communication with the coolant reservoir. The pump operates to pump coolant fluid from the coolant reservoir and into the coolant circuit of the electric motor. Attached Figure Description

[0006] Figure 1 A schematic layout illustrating an embodiment of the coolant circuit of an electric vehicle drive module;

[0007] Figure 2 This is a cross-sectional view of an embodiment of an electric vehicle drive module;

[0008] Figure 3 This is a cross-sectional view of an electric vehicle drive module, showing a first embodiment of the coolant passage;

[0009] Figure 4 This is a cross-sectional view of an electric vehicle drive module, showing a second embodiment of the coolant passage;

[0010] Figure 5 It is a graph showing the volumetric flow rate modeled for the drive module of an electric vehicle; and

[0011] Figure 6 This is a flowchart of an embodiment of a method for providing coolant in an electric motor of an electric vehicle drive module. Detailed Implementation

[0012] An embodiment of the electric vehicle drive module 10 with enhanced rotor cooling measures is shown in the accompanying drawings and detailed in this specification. Unlike previous arrangements, the rotation of the rotor of the electric vehicle drive module 10 participates in and directly affects the supply of coolant within the components of the electric vehicle drive module 10. The increased volumetric flow rate of coolant within the components, along with enhanced cooling effects and efficiency at the rotor and stator of the electric vehicle drive module 10, results in improved cooling. According to various embodiments, when the increased coolant flow is supplied by the rotation of the rotor, the pumping of coolant through portions of the electric vehicle drive module 10 can be throttled, or otherwise reduced or completely stopped. The overall system efficiency of the electric vehicle drive module 10 can thus be improved, ultimately reducing energy consumption from the accompanying vehicle battery.

[0013] Furthermore, as used herein and unless otherwise specifically stated, the terms “axially,” “radially,” and “circumferentially,” and their associated grammatical forms, are generally used with reference to the circular and cylindrical shapes of some of the electric motors and their components shown. In this sense, “axially” refers to a direction generally along or parallel to the central axis of the circular and cylindrical shape, “radially” refers to a direction generally along or parallel to the radius of the circular and cylindrical shape, and “circumferentially” refers to a direction generally along the circumference of the circular and cylindrical shape or in a direction similar to the circumference of the circular and cylindrical shape. Additionally, the terms “downstream” and “upstream” are used herein with respect to the direction of coolant flow from the coolant reservoir, such that “downstream” refers to coolant flow in the direction of movement from the coolant reservoir, while “upstream” refers to coolant flow in the opposite direction. Furthermore, the phrase “fluidly connected” and its associated grammatical forms are used herein to refer to the convenience of fluid flow (e.g., coolant flow) between and within the relevant components and locations.

[0014] In general, depending on different automotive industry applications, the electric vehicle drive module 10 can be equipped in hybrid electric vehicle (HEV) powertrain systems and battery electric vehicle (BEV) powertrain systems. The electric vehicle drive module 10 is used to drive the rotation of the wheels for hybrid electric vehicles or battery electric vehicles. Depending on different embodiments and their applications, the electric vehicle drive module 10 can exhibit various designs and constructions and can have various components. Its components are integrated together in a larger packaged unit. In the embodiments shown in the accompanying drawings, and with reference to... Figure 2 The electric vehicle drive module 10 includes a power electronics assembly 12, a gear assembly 14, and an electric motor 16 as its main components; however, in other embodiments, the electric vehicle drive module 10 can have more, fewer, and / or different components. Furthermore, a housing 18 is provided to support and mount the components of the electric vehicle drive module 10 together. The housing 18 can be made of a plurality of walls 20, covers, plates, and / or other structures (depending on the embodiment) that can be connected to each other, such as via bolts or via another connection technique. Specifically, the housing 18 has a main portion and a wall 22 surrounding the electric motor 16, and an inner wall 24 that radially extends to the shaft of the electric motor 16 (described below) and axially lies between the electric motor 16 and the gear assembly 14. End walls 26 of the housing 18 are located on the opposite side of the electric motor 16 with respect to the gear assembly 14.

[0015] Power electronics 12 is used to control and convert the electrical power in the electric vehicle drive module 10. Power electronics 12 can include one or more of the following components: an onboard charger, a controller, an inverter, and a converter, among others. Gear assembly 14 is used to transmit rotation and torque from the electric motor 16 to the output shaft. The output shaft can be connected to the axle shaft of the accompanying vehicle's wheels. Gear assembly 14 can have various designs, configurations, and components depending on different embodiments and is partly or more dependent on the architecture of the powertrain in which the electric vehicle drive module 10 is equipped. Figure 2 In this embodiment, the gear assembly 14 and the shaft of the electric motor 16 are coaxially arranged and take the form of a planetary gear set and a differential. The planetary gear set can include a sun gear, multiple planetary gears, a ring gear, and a planet carrier. For the wheels driven to rotate by the electric vehicle drive module 10, the differential is used to allow one wheel to rotate faster than the other wheel during vehicle cornering. Furthermore, as... Figure 2 As illustrated, a gear assembly housing 28 is provided to house the gear assembly 14. The gear assembly housing 28 can be mounted onto the housing 18. However, in other embodiments, the gear assembly 14 may have more, fewer, and / or different components compared to that presented herein. For example, the gear assembly 14 may have an off-axis arrangement relative to the shaft of the electric motor 16, rather than... Figure 2 The coaxial arrangement is depicted in the figure.

[0016] An electric motor 16 is used to provide the rotation and torque that ultimately drives the vehicle wheels. The electric motor 16 imparts movement and rotation to the gear assembly 14 and is housed within a housing 18. The electric motor 16 can have various designs, configurations, and components depending on different embodiments and is partly or more dependent on the architecture of the powertrain in which the electric vehicle drive module 10 is located. The electric motor 16 can be an alternating current (AC) motor and can be a synchronous motor. In the embodiments shown in the accompanying drawings, and continuing to refer to... Figure 2 The electric motor 16 includes a stator 30 and a rotor 32 as its main components. The stator 30 receives electricity from the vehicle battery via a power electronics assembly 12, thereby causing the rotor 32 to rotate while the stator 30 remains stationary relative to it. The stator 30 has a plurality of windings 34 with winding ends 36, and the rotor 32 has a shaft 42. When the electric motor 16 is activated, the shaft 42 rotates, and the input gear portion 40 of the shaft 42 drives the movement and rotation of the gear assembly 14. Figure 2In one embodiment, shaft 42 and inner shaft 38 are arranged in a through-shaft configuration; however, in other embodiments, shaft 38 may have other arrangements lacking inner shaft 38. Furthermore, bearing 44 is capable of providing support and facilitating the rotation of certain components in various locations during the use of the electric vehicle drive module 10. However, in other embodiments, electric motor 16 may be other types of motors and may have more, fewer, and / or different components compared to those presented herein.

[0017] Excessive heat is typically generated by the electric motor 16 during the use of the electric vehicle drive module 10, which can ultimately degrade performance. To dissipate this heat, conventional electric vehicle drive modules are equipped with cooling systems that distribute coolant to certain parts and locations of their electric motors. These cooling systems may include a coolant supply source, a coolant pump, and a series of channels and nozzles near the stator of the electric motor, among other possibilities. While sufficient in some environments, increased cooling has been observed to be generally beneficial, and the coolant pump can constitute an inefficient use of energy throughout the system.

[0018] refer to Figure 1 and Figure 2The electric vehicle drive module 10 is equipped with a cooling system 46 to dissipate heat generated in the electric motor 16 and other locations, as well as in other components of the electric vehicle drive module 10. According to this embodiment, the cooling system 46 includes a coolant reservoir 48, a coolant pump 50, and a coolant circuit 52; however, in other embodiments, the cooling system 46 may have more, fewer, and / or different components. The coolant reservoir 48 is established within the housing 18 and houses a supply source of coolant fluid 54. The coolant fluid 54 can be in the form of oil. The coolant reservoir 48 is defined within the housing 18 and is defined by one or more of the walls 20. During and outside use of the electric vehicle drive module 10, the coolant fluid 54 may arrive at and / or deposit in the coolant reservoir 48 at different times. The coolant pump 50 operates to pump the coolant fluid 54 from the coolant reservoir 48 and through the coolant circuit 52. A pump supply passage 56 is fluidly connected to the coolant reservoir 48 and to the coolant pump 50. The coolant pump 50 is also fluidly connected to a coolant circuit 52, which can be located downstream of the coolant pump 50. According to this embodiment, the coolant circuit 52 includes a distribution box 58, a coolant passage 60, a constriction section 62, a stator spray section 64, a rotor spray section 66, and a rotor feed passage (not shown) that feeds coolant fluid from the pump 50 to the rotor 32; however, in other embodiments, the coolant circuit may have other configurations with more, fewer, and / or different components. Coolant fluid 54 is distributed throughout the coolant circuit 52. The coolant fluid 54 can travel downstream from the distribution box 58 for auxiliary purposes, such as to the gear assembly 14 in the electric vehicle drive module 10. Figure 1 (Ref. 68) and flows downstream via coolant passage 60 to stator spray section 64 for discharge and through constriction section 62. According to an example, discharge via stator spray section 64 can be directed to winding end 36. Further downstream, coolant fluid 54 travels to and through rotor passage and proceeds to rotor spray section 66 for discharge. Rotor passage can be located inside rotor 32 to distribute coolant fluid 54 within rotor stacks, and other possibilities exist.

[0019] To increase the volumetric flow rate of the coolant fluid 54 in the cooling system 46—and particularly the volumetric flow rate of the coolant fluid 54 to the rotor 32—to enhance the cooling effect and efficiency of the electric motor 16, a coolant passage 70 is introduced. The coolant passage 70 more directly and immediately connects the shaft 42 of the rotor 32 and the rotor's cooling infrastructure, as well as the coolant reservoir 48, together. The coolant fluid 54 in the coolant reservoir 48 can therefore flow more directly and immediately to the rotor 32 via the coolant passage 70, as described in more detail below. The coolant passage 70 can form part of a larger cooling system 46. The coolant passage 70 is located within the housing 18 and at least partially spans between the shaft 42 and the coolant reservoir 48, with an inlet 72 in fluid communication with the coolant reservoir 48. The outlet 74 of the coolant passage 70 is located downstream of the inlet 72 and in fluid communication with the coolant passage of the rotor 32. In different embodiments, depending in part on the design and construction of the electric vehicle drive module 10 and its components, the coolant passage 70 can have various designs and constructions. The coolant passage 70 is located in one or more of the walls 20 of the housing 18 and is therefore at least partially defined by one or more of the walls 20 of the housing 18. In at least some embodiments, the wall(s) defining the coolant passage 70 also defines a coolant reservoir 48.

[0020] Figure 3 and Figure 4 An example embodiment of coolant passage 70 is presented. Figure 3 In one embodiment, the coolant passage 70 is located in the inner wall 24 and extends vertically from the coolant reservoir 48 to the shaft 42 (here, "vertically" refers to...) Figure 2(The electric vehicle drive module 10 is used for orientation). At the inlet 72, the coolant passage 70 is open to the coolant reservoir 48 to receive and receive the coolant fluid 54 within the coolant passage 70. At the outlet 74, the coolant passage 70 is fluidly connected to a second coolant passage 76 for the flow of coolant fluid 54 thereto. The second coolant passage 76 is located in the shaft 42 and is arranged collinearly with the coolant passage 70. Downstream of the second coolant passage 76, the coolant fluid 54 travels to a third coolant passage 78 at the third inner shaft 38. The third coolant passage 78 is located inside the shaft 42. From there, the coolant fluid 54 is distributed to and passes through the rotor passage and to the rotor spray section 66. Furthermore, a sealing section 80 can be provided near the joint of the coolant passages 70 and 76, and at the joint at the axial end of the shaft 42, both of which, according to this embodiment, prevent unwanted coolant leakage. According to this embodiment, between inlet 72 and outlet 74, coolant passage 70 exhibits both linear and radial paths (“radial” is used here relative to the cylindrical shape of shaft 42). In other embodiments where shaft 42 lacks an internal shaft, coolant passage 70 may be in direct fluid communication with a third coolant passage 78.

[0021] exist Figure 4 In this embodiment, the coolant passage 70 is located in the end wall 26 and extends from the coolant reservoir 48 to the shaft 42, particularly to the inner shaft 38. At the inlet 72, the coolant passage 70 is open to the coolant reservoir 48 to receive and receive the coolant fluid 54 within the coolant passage 70. At the outlet 74, the coolant passage 70 is fluidly in communication with the cavity 82 for supplying a flow of coolant fluid 54 thereto. The cavity 82 is partially formed by the surface of the end wall 26 and the outer surface 84 of the inner shaft 38. Downstream of the cavity 82, the coolant fluid 54 reaches the third coolant passage 78 for distribution to and through the rotor passage and to the rotor spray section 66. Furthermore, according to this embodiment, the cavity 82 is pressurized by the coolant pump 50 and receives the coolant fluid 54 downstream of the distribution tank 58 via the coolant passage 60. Between the inlet 72 and the outlet 74, the coolant passage 70 exhibits a non-linear path with multiple bends along its course.

[0022] Furthermore, in this embodiment, a check valve 86 is located and disposed within the coolant passage 70. The check valve 86 is positioned downstream of the inlet 72 and upstream of the outlet 74. The check valve 86 allows the flow of coolant fluid 54 through the coolant passage 70 in a downstream direction from the inlet 72 to the outlet 74, and prevents the flow of coolant fluid 54 in the opposite, upstream direction from the outlet 74 to the inlet 72. Undesired backflow to the coolant reservoir 48 is thus prevented via the check valve 86. Backflow has been observed to occur when the coolant passage 70 is not affected by lower pressure conditions and the coolant fluid 54 does not flow downstream of the inlet 72, as described below. Additionally, the check valve may also be located in… Figure 3 The coolant passage 70 is implemented in the embodiment. However, in other embodiments, the coolant passage 70 may be located in other walls of the housing 18 and / or more than a single coolant passage 70 may exist in the same housing 18, such as having Figure 3 and Figure 4 Both of them are in the coolant passage 70.

[0023] During the use of the electric vehicle drive module 10, coolant fluid 54 is drawn from the coolant reservoir 48 and flows through the coolant passage 70 to the rotor 32. Without intending to limit it to a particular theory of causality, it is considered that the rotation of the shaft 42 and the pressure difference between the coolant flow pumped into the rotor passage via the coolant pump 50 and the coolant flow exiting the rotor 32 (such as via the rotor spray section 66 or otherwise) contribute to and induce the conditions under which the coolant fluid 54 flows through the coolant passage 70. During the rotational motion of the rotor 32, the centrifugal force experienced by the coolant fluid 54 within the rotor 32 is also considered to affect the coolant fluid flow through the coolant passage 70. Internal constraints within the rotor 32—some intentionally, some not—limit the coolant flow exiting the rotor 32 compared to the pumped coolant flow that can be used to enter the rotor passage.

[0024] Therefore, a lower pressure region 88 or a negative pressure region may be created. The lower pressure region 88 operates to draw coolant fluid 54 through the coolant passage 70. The lower pressure region 88 can be formed downstream of the coolant passage 70 and fluidly communicate with it. According to various embodiments, the fluid communication can be direct and immediate without intervening gaps and / or channels, or it can be indirect, such as through intervening gaps and / or channels downstream of the coolant passage 70. Once formed, the accompanying lower pressure conditions of the lower pressure region 88 are used to draw coolant fluid 54 from the coolant reservoir 48 and through the coolant passage 70. Figure 3 and Figure 4In one embodiment, the lower pressure region 88 can be located adjacent to the inner shaft 38, such as near the outer surface 84 and near the outer diameter of the inner shaft 38, and can be located adjacent to the shaft 42, such as near the outer diameter of the shaft 42. Figure 3 For example, a lower pressure region 88 can be positioned adjacent to and downstream of the outlet 74 of the second coolant passage 76, or at least these locations can be subjected to lower pressure conditions. Figure 4 As another example, a lower pressure region 88 can be located downstream of outlet 74 and adjacent to cavity 82, or at least these locations can be subjected to lower pressure conditions. In this respect, Figure 3 and Figure 4 The guide line for the lower pressure region 88 is intended to indicate the approximate location of the lower pressure conditions and is not necessarily the precise and unique location of the lower pressure region 88.

[0025] Figure 5 The graph illustrates the increased volumetric flow rate of coolant at rotor 32, which can be provided by the implementation of coolant channel 70 in electric vehicle drive module 10. Figure 5 The images were generated by simulations performed on a rotor with coolant passages similar to those described herein. As described, a coolant pump delivering coolant fluid is included in the simulation. The rotor was simulated at a rotational speed of 5000 revolutions per minute (RPM). Those skilled in the art should be aware that other simulations may produce different results. Figure 5 In the graph, the x-axis represents the cumulative time step, which can be expressed in seconds (sec), where 1000 = 1 sec, 2000 = 2 sec, 3000 = 3 sec, 4000 = 4 sec, 5000 = 5 sec, and 6000 = 6 sec. The y-axis represents the volumetric flow rate in liters per minute (lpm). Line 110 (rotor-sump inflow (positive)) represents the flow of coolant fluid from the coolant reservoir and through the coolant passages. Line 120 (rotor left outlet (negative)) represents the flow of coolant fluid leaving the rotor on its left side (here, "left side" refers to...). Figure 2 The orientation of the electric vehicle drive module 10 is used. Line 130 (rotor right-side outlet (negative)) indicates the flow of coolant fluid exiting the rotor on its right side (here, "right side" refers to...). Figure 2 (The orientation of the electric vehicle drive module 10 is used).

[0026] As illustrated in the figure, at time 0 seconds, there is no coolant flow. At approximately time 0.5 seconds, coolant flow begins at the coolant passage and on the left and right sides of the rotor. At approximately time 1.0 seconds, a flow of approximately 15.5 lpm of coolant fluid is observed at the coolant passage, approximately 7 lpm on the left side of the rotor, and approximately 9 lpm on the right side of the rotor. Furthermore, at approximately time points of 2.0, 3.0, 4.0, 5.0, and 6.0 seconds, a flow of approximately 15.5 lpm of coolant fluid is maintained at the coolant passage, approximately 8 lpm on the left side of the rotor, and approximately 9.5 lpm on the right side of the rotor. The additional 2.0 lpm of coolant fluid flowing from the left and right sides of the rotor—relative to the coolant fluid at the coolant passage—is assumed to be supplied by the coolant pump in the simulation. Furthermore, simulations showed that once the rotor is primed with coolant fluid and the coolant fluid completely fills the rotor, the rotor coolant passage provides a pumping function for the flow of coolant fluid to the rotor. Priming was observed at 5 seconds and thereafter. In the primed state, the coolant fluid flow rate was maintained at approximately 15.5 lpm. Enhanced cooling can therefore be affected at both the rotor and stator. In summary, the implementation of coolant passage 70 in the embodiments described herein demonstrates an increase in the volumetric flow rate of coolant fluid through rotor 32 by approximately 15 lpm. Furthermore, it has been found that the volumetric flow rate of coolant fluid 54 through coolant passage 70 is at least partially a function of the rotational speed of rotor 32—an increased rotational speed provides an increased volumetric flow rate.

[0027] According to various embodiments, the increased volumetric flow rate of the coolant fluid 54 via the coolant passage 70 can supplement, or replace, the coolant flow pumped by the coolant pump 50. For example, the coolant pump 50 can be throttled to reduce the flow rate to the coolant passage 60. Referring now... Figure 6This describes an embodiment of method 210 for providing coolant fluid 54 in an electric motor 16. Method 210 involves multiple steps and may have more, fewer, and / or different steps compared to those presented in other embodiments herein. In a first step 220, a first volumetric flow rate of coolant fluid 54 is provided to the electric motor 16 and to the stator 30 and rotor 32 via coolant pump 50. This may constitute a first operating state of coolant pump 50. According to an example, first step 220 may be performed without coolant fluid 54 being provided to rotor 32 via coolant passage 70. In other words, according to different examples, coolant pump 50 may pump coolant fluid 54 at a first volumetric flow rate before, and after, and before the second step 230, a filling state is established in rotor 32. The second step 230 of method 210 involves coolant fluid 54 being drawn from coolant reservoir 48 and through coolant passage 70 by means of rotation of shaft 42 and pressure differential as described above. The third step 240 involves providing a second volumetric flow rate of coolant fluid 54 to the electric motor 16 and to the stator 30 and rotor 32 via the coolant pump 50. This can constitute a second operating state of the coolant pump 50. The second volumetric flow rate can begin after the coolant fluid 54 is drawn from the coolant reservoir 48 and through the coolant passage 70 by the rotation of the shaft 42 and the pressure difference described above. That is, the third step 240 can be performed after the second step 230. The second volumetric flow rate in the third step 240 can have a smaller value than the first volumetric flow rate in the first step 220. However, other steps of method 210 can involve terminating the supply of coolant fluid 54 via the coolant pump 50. The supply of coolant fluid 54 can be terminated after the coolant fluid 54 is drawn from the coolant reservoir 48 and through the coolant passage 70 by the rotation of the shaft 42 and the pressure difference. This can involve deactivating the coolant pump 50, where no volumetric flow rate of coolant is pumped to the electric motor 16. Instead, coolant fluid 54 is drawn from coolant reservoir 48 and supplied to electric motor 16 via coolant passage 70. Furthermore, in other embodiments, coolant pump 50 may have other operating states that provide other volumetric flow rates.

[0028] It should be understood that the foregoing description is a description of one or more embodiments of the present invention. The present invention is not limited to the specific embodiments disclosed herein, but is defined solely by the following claims. Furthermore, the statements contained in the foregoing description relate to specific embodiments and should not be construed as limiting the scope of the invention or the definition of terms used in the claims, unless the terms or phrases are expressly defined above. Various other embodiments and various variations and modifications to the disclosed embodiments will become apparent to those skilled in the art. All such other embodiments, variations, and modifications are intended to fall within the scope of the appended claims.

[0029] As used in this specification and claims, the terms “for example,” “like,” “for instance,” “such as,” and “like,” as well as the verbs “comprising,” “having,” “including,” and other verb forms thereof, when used in conjunction with a list of one or more components or other items, shall each be interpreted as open-ended, meaning that the list should not be considered to exclude other additional components or items. Other terms shall be interpreted using their broadest reasonable meaning, unless they are used in a context that requires a different understanding.

Claims

1. An electric vehicle drive module, comprising: case; An electric motor, located within the housing, the electric motor having a stator and a rotor, the rotor having a shaft; A gear assembly that is rotatably driven by the shaft; A coolant reservoir, which is built into the housing; A coolant passage is located in the wall of the housing and is in fluid communication with the shaft and the coolant reservoir, wherein coolant is drawn from the coolant reservoir and through the coolant passage when the shaft rotates; A check valve located in the coolant passage allows coolant to flow from the coolant reservoir and through the coolant passage to the downstream of the coolant reservoir, and prevents coolant from flowing through the coolant passage into the coolant reservoir. and A pump in fluid communication with the coolant reservoir, the pump supplying coolant from the coolant reservoir and to the coolant circuit of the electric motor, the pump having a first operating state when no coolant is drawn from the coolant reservoir through the coolant channel, and a second operating state when coolant is drawn from the coolant reservoir through the coolant channel.

2. The electric vehicle drive module as claimed in claim 1, wherein the wall of the housing is the inner wall of the housing, and the coolant passage is located in the inner wall.

3. The electric vehicle drive module as described in claim 2, wherein the inner wall is axially located between the electric motor and the gear assembly.

4. The electric vehicle drive module as claimed in claim 1, wherein the wall of the housing is an end wall of the housing, and the coolant passage is located in the end wall.

5. The electric vehicle drive module of claim 1, further comprising a lower pressure region adjacent to the shaft and in fluid communication with the coolant passage.

6. The electric vehicle drive module as claimed in claim 1, further comprising a second coolant passage located at the shaft, the coolant passage being in fluid communication with the second coolant passage.

7. The electric vehicle drive module as claimed in claim 6, wherein the second coolant passage is located in the shaft.

8. The electric vehicle drive module of claim 1, wherein coolant is drawn from the coolant reservoir and travels through the coolant passage into the downstream coolant circuit of the electric motor.

9. The electric vehicle drive module of claim 1, wherein the first operating state of the pump provides a greater volumetric flow rate of coolant to the cooling circuit compared to the second operating state.

10. A method for providing coolant in an electric motor of an electric vehicle drive module, the method comprising: A first volumetric flow rate of coolant is provided to the electric motor via a pump, the pump pumping coolant from the coolant reservoir of the electric vehicle drive module and pumping it into the coolant circuit of the electric motor; Coolant is drawn from the coolant reservoir through the coolant channel via the rotation of the rotor shaft of the electric motor, and the coolant channel is in fluid communication with the coolant circuit; as well as After the coolant is drawn from the coolant reservoir through the coolant passage via the rotation of the rotor shaft of the electric motor, a second volumetric flow rate of coolant is provided to the coolant circuit via the pump, the second volumetric flow rate of coolant being less than the first volumetric flow rate of coolant.

11. The method of providing coolant in the electric motor of the electric vehicle drive module as described in claim 10, wherein a first volumetric flow rate of coolant is provided to the electric motor via the pump when no coolant is drawn from the coolant reservoir through the coolant passage.

12. The method of providing coolant in the electric motor of the electric vehicle drive module as described in claim 10, further comprising terminating the supply of coolant to the coolant circuit via the pump after the coolant is drawn from the coolant reservoir through the coolant passage by the rotation of the rotor shaft of the electric motor, and supplying coolant to the coolant circuit only via the coolant passage.

13. The method of providing coolant in the electric motor of the electric vehicle drive module as described in claim 10, further comprising fluidly communicating a lower pressure generated when the rotor shaft of the electric motor rotates with the coolant passage.

14. The method of providing coolant in the electric motor of the electric vehicle drive module as described in claim 10, further comprising communicating the coolant reservoir and the rotor shaft via the coolant channel.

15. An electric vehicle drive module, comprising: A housing having an inner wall, an end wall, or both the inner wall and the end wall; An electric motor, located within the housing, the electric motor having a stator and a rotor, the rotor having a shaft; A gear assembly that is rotatably driven by the shaft; A coolant reservoir, which is built into the housing; A coolant passage is located in the inner wall, the end wall, or both the inner wall and the end wall, and the coolant passage is in fluid communication with the coolant reservoir and the coolant circuit of the electric motor. A lower pressure region adjacent to the shaft, the lower pressure region being in fluid communication with the coolant passage; and A pump, which is in fluid communication with the coolant reservoir, pumps coolant from the coolant reservoir and into the coolant circuit of the electric motor, wherein the pump has a first operating state when no coolant is drawn from the coolant reservoir through the coolant channel, and a second operating state when coolant is drawn from the coolant reservoir through the coolant channel, the first operating state of the pump providing a greater volumetric flow rate of coolant to the cooling circuit than the second operating state.

16. The electric vehicle drive module of claim 15, wherein the lower pressure in the lower pressure region draws coolant from the coolant reservoir and through the coolant passage.

17. The electric vehicle drive module as claimed in claim 15, further comprising a check valve located in the coolant passage.

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