Method, system and apparatus for passive end turn cooling of electric motors using gravity

Abstract

In various embodiments, methods, systems, and vehicle devices are provided. A system providing a gravity driver to distribute a flow of coolant oil includes a nozzle to direct a flow of coolant oil over a surface of an electric motor, wherein the flow of coolant oil is caused by the gravity driver; a connector coupled to the nozzle, the connector enabling the nozzle to sway in response to external forces encountered by operation of the device and to distribute coolant oil over an outer surface of the electric motor; and a counterweight coupled to the nozzle, the counterweight providing opposition to the external forces encountered by the operation to enable the nozzle to sway in a manner that enables the coolant oil to be distributed evenly over the outer surface of the electric motor.

Description

TECHNICAL FIELD

[0001] The technical field generally relates to oil-cooled motors, and more particularly to methods, systems, and apparatus for flow control of cooling oil to distribute the cooling oil evenly over the windings of a motor stator to prevent hot spots that affect the operability and life of the motor. BACKGROUND

[0002] Electric vehicles (EVs) are in common use and are a replacement for internal combustion engine (ICE) vehicles to reduce carbon emissions in the atmosphere. EVs operate via electric motors powered by battery energy. In some cases, the electric motor of an EV can use an oil cooling system. In such cases, engine oil is used as a coolant to remove heat from the motor. Heat from the motor system is transferred via a heat exchanger from the entire surface of the windings of the electric motor.

[0003] In direct oil-cooled motor systems, the coolant (oil) directly contacts the hot surface (i.e., winding end turns as an example in an oil motor). To obtain the best cooling performance of an oil motor, it is necessary or optimal to have an even distribution of cooling oil over the hot surface of the winding end turns of the oil motor to remove heat from the desired target area.

[0004] However, in gravity-driven coolant oil flow systems, the direction of the coolant oil flow is affected by external conditions that cause the gravity-driven coolant oil flow to not be evenly distributed over the planar surface exposed to the coolant oil flow or the desired hot surface. For example, the gravity-driven oil flow can be disrupted or disturbed by external factors such as road slope (inclination of the road) and lateral acceleration when the vehicle is turning. When the vehicle is in this type of motion, the effect of the transition is that the oil flow is no longer a continuous even flow over the winding surface or covering the target area. Instead, the oil flow is uneven and can even miss the target area, and thus the oil coverage can or will be significantly reduced; this in turn results in a degrading effect on the cooling efficiency. For example, due to the uneven distribution of the oil flow, hot spots can occur due to poor cooling of the motor windings, which can result in early failure of the electrical insulation, as compared to the failure typically expected for the particular type of insulation used in the oil-cooled motor; this can also result in overall failure of the oil-cooled motor.

[0005] It is desirable to have a mechanism to improve the cooling oil distribution for a gravity-driven end turn coolant system for a motor that is subject to the common negative effects of external forces or disturbances to the cooling oil flow that can be caused, for example, by the vehicle traversing uneven surfaces or exhibiting lateral acceleration effects that interrupt or prevent the continuous even flow of the cooling oil over the motor windings.

[0006] It is desirable to vary the cooling oil flow direction in a manner that counteracts the effects of oil flow disturbances caused by different (i.e., uneven) road slopes and lateral accelerations experienced by the vehicle jolted oil to enhance oil distribution and improve cooling efficiency.

[0007] Further features and characteristics of the present application will become apparent from the subsequent detailed description and appended claims, taken in conjunction with the accompanying drawings and the foregoing background. SUMMARY

[0008] A system, apparatus, and method for implementing a counterweight to provide opposition to external forces and direct a flow of coolant oil of a gravity driven coolant system to a target area of an electric motor are disclosed.

[0009] In one example embodiment, a system to provide gravity driven to distribute a flow of coolant oil in an apparatus is provided, comprising: a nozzle to direct a flow of coolant oil over a surface of an electric motor, wherein the flow of coolant oil is caused by gravity driven; a connector coupled to the nozzle, the connector enabling the nozzle to sway in response to external forces encountered by operation of the apparatus and to distribute the coolant oil over an outer surface of the electric motor; and a counterweight coupled to the nozzle, the counterweight providing opposition to the external forces encountered by operation to enable the nozzle to sway in a manner that enables the coolant oil to be distributed evenly over the outer surface of the electric motor.

[0010] In at least one example embodiment, the system includes the nozzle coupled to the connector, the connector including a pivot to enable the nozzle to sway in opposite directions by torque applied from the counterweight in response to external forces encountered by operation of the vehicle.

[0011] In at least one example embodiment, the system includes the counterweight coupled to a set of gears, the set of gears providing counter-clockwise and clockwise torque in response to the external forces to enable the nozzle to sway in a manner that enables the coolant oil to be distributed evenly over the outer surface of the electric motor.

[0012] In at least one example embodiment, the system includes the outer surface of the electric motor, the outer surface including winding end turns of a stator, wherein the end turns are evenly distributed with coolant oil by the nozzle swaying that is partially controlled by the counterweight.

[0013] In at least one example embodiment, the system includes the counterweight, the counterweight including a passive device that senses vehicle motion and implements opposition by providing counter-clockwise and clockwise torque in response to the external forces to enable the nozzle to sway in a manner that enables the coolant oil to be distributed evenly over the outer surface of the electric motor.

[0014] In at least one example embodiment, the system includes a linkage that couples the set of gears to a counterweight to reverse the direction of the nozzle swing in response to an external force on the nozzle resulting from vehicle operation.

[0015] In at least one example embodiment, the system includes the set of gears, the set of gears including a first gear coupled to a counterweight, the first gear providing a counter-clockwise torque, and a second gear coupled to the first gear and a linkage, the second gear providing a clockwise torque driver to counteract an external force causing the nozzle to swing to receive a reverse force.

[0016] In at least one example embodiment, the connector includes a rubber connector.

[0017] In another example embodiment, a vehicle apparatus is provided. The vehicle apparatus includes a gravity driver to distribute a flow of coolant oil from a nozzle onto an outer surface of an electric motor; a connector coupled to the nozzle, the connector enabling the nozzle to swing in response to an external force encountered by vehicle operation and to distribute the coolant oil on the outer surface of the electric motor; and a counterweight coupled to the nozzle, the counterweight providing opposition to the external force encountered by the vehicle operation to cause the nozzle to swing in a manner that enables the coolant oil to be distributed evenly on the outer surface of the electric motor.

[0018] In at least one example embodiment, the vehicle apparatus includes a nozzle coupled to a connector, the connector including a pivot to enable the nozzle to swing in an opposite direction by a torque applied from a counterweight in response to an external force encountered by vehicle operation.

[0019] In at least one example embodiment, the vehicle apparatus includes a counterweight coupled to a set of gears, the set of gears providing counter-clockwise and clockwise torque in response to an external force to cause the nozzle to swing in a manner that enables the coolant oil to be distributed evenly on an outer surface of an electric motor.

[0020] In at least one example embodiment, the vehicle apparatus includes an outer surface of an electric motor, the outer surface including a winding end turn of a stator, wherein the end turn is evenly distributed with coolant oil by a nozzle swing that is partially controlled by a counterweight.

[0021] In at least one example embodiment, the vehicle apparatus includes a counterweight including a passive system that senses vehicle motion and implements opposition by providing counter-clockwise and clockwise torque in response to an external force to cause the nozzle to swing in a manner that enables the coolant oil to be distributed evenly on an outer surface of an electric motor.

[0022] In at least one example embodiment, the vehicle apparatus includes a lever that couples a set of gears to a counterweight to reverse the direction of the nozzle swing in response to an external force on the nozzle resulting from vehicle operation.

[0023] In at least one example embodiment, the set of gears includes a first gear coupled to the counterweight that provides a counter-clockwise torque and a second gear coupled to the first gear and the link that provides a clockwise torque driver to counteract the external force causing the nozzle swing to receive a reversing force.

[0024] In at least one example embodiment, the vehicle apparatus includes a lever that acts like a swing lever to resist nozzle movement.

[0025] In yet another example embodiment, a method of uniformly distributing coolant oil on an outer surface of an electric motor is provided. The method includes directing a flow of coolant oil on an outer surface of an electric motor using gravity driven through a nozzle; coupling the nozzle to a rubber connector that enables the nozzle to swing in response to an external force encountered by vehicle movement, and that enables the nozzle to distribute coolant oil on the outer surface of the electric motor, wherein the external force results from road grade and vehicle acceleration; and coupling a counterweight to the nozzle to provide opposition to the external force to cause the nozzle to swing in a manner that enables the coolant oil to be uniformly distributed on the outer surface of the electric motor.

[0026] In at least one example embodiment, the method includes a connector that includes a pivot mechanism to enable the nozzle to swing in an opposite direction by responding to torque exerted from the counterweight in response to the external force.

[0027] In at least one example embodiment, the method includes coupling the counterweight to a set of gears that provide counter-clockwise and clockwise torque in response to the external force to cause the nozzle to swing in a manner that enables the coolant oil to be uniformly distributed on the outer surface of the electric motor.

[0028] In at least one example embodiment, the method includes the outer surface of the electric motor including a winding end turn of a stator; and the end turn is uniformly distributed with coolant oil by the nozzle swing that is partially controlled by the counterweight. BRIEF DESCRIPTION OF DRAWINGS

[0029] In the following exemplary embodiments will be described with reference to the following drawings, wherein like numbers like elements refer to, and wherein:

[0030] Figure 1A and Figure 1BAn exemplary side view showing a wetted area of a surface of an end turn winding of a stator of an electric motor, which varies according to different accelerations of an electric vehicle of an exemplary embodiment is shown;

[0031] Figure 2 A side view schematic showing a wetted area of a surface of an end turn winding of a stator of an electric motor according to an exemplary embodiment is shown;

[0032] Figure 3A 、 Figure 3B and Figure 3C An exemplary diagram showing application of a counterweight in response to different external forces caused by vehicle operation for achieving flow distribution of coolant oil on an outer surface of an electric motor via nozzles according to an exemplary embodiment is shown;

[0033] Figure 4A 、 Figure 4B and Figure 4C A side view schematic of a gravity driven coolant system according to an exemplary embodiment is shown, wherein flow passes through an end turn winding of a stator of an electric motor; and

[0034] Figure 5 An exemplary flow diagram showing implementation of counterweight torque in response to different external forces caused by vehicle operation for achieving flow distribution of coolant oil on an outer surface of an electric motor via nozzles according to an exemplary embodiment is shown. DETAILED DESCRIPTION

[0035] The following detailed description is merely exemplary in nature and is not intended to limit the application and use. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, summary or the following detailed description.

[0036] Embodiments of the present disclosure can be described herein in terms of functional and / or logical block components and various processing steps. It should be appreciated that such block components can be realized by any number of hardware, software, and / or firmware components configured to perform the specified functions. For example, an embodiment of the present disclosure can employ various integrated circuit components, e.g., memory elements, digital signal processing elements, logic elements, look-up tables, or the like, which can carry out a variety of functions under the control of one or more microprocessors or other control devices. In addition, those skilled in the art will appreciate that embodiments of the present disclosure can be practiced with

[0037] The present disclosure describes systems, devices, and methods for a gravity driven coolant flow system to prevent the design goal of coolant oil missing the hot surface of an electric motor in the presence of external disturbances such as non-zero road slope and / or lateral acceleration due to cornering. In this case, the flow direction is controlled by the torque force from the counterweight to counteract the disturbance caused by external forces.

[0038] The present disclosure describes systems, devices, and methods for a gravity driven coolant flow system that operates as a passive system and does not require active sensors, actuators, and controllers that can add cost and complexity to the cooling oil system.

[0039] The present disclosure describes systems, devices, and methods for a gravity driven coolant flow system that operates as a passive system and does not require active sensors, actuators, and controllers that can add cost and complexity to the cooling oil system.

[0040] Figure 1A and Figure 1B A side view of a wetted area of an end turn winding surface of a stator of an electric motor (of coolant oil) is shown, which varies depending on different accelerations of an electric vehicle according to exemplary embodiments. In Figure 1A In, a nozzle 10 is shown for distributing a coolant oil flow over a hot surface or planar area (e.g., an end turn winding) of an electric motor, wherein the coolant oil flow is caused by a gravity driven induction. The coolant oil flow 30 is evenly distributed over the surface 20, wherein the coolant oil is directed to a plurality of target areas on the surface 20, as there is no external disturbance caused by zero lateral acceleration. In Figure 1B In, a significant reduction of coolant oil over a plurality of target areas of the surface 20 is shown, as the coolant oil flow 30 is swung away from the target areas due to forces imposed by vehicle acceleration (in this case, 1 G lateral acceleration). This results in a significant reduction of the wetted area exposed to coolant oil, and this in turn results in poor cooling performance.

[0041] Figure 2 An exemplary schematic of a side view of a wetted area of a surface of an end turn winding of a stator of an electric motor is shown according to exemplary embodiments. In Figure 2In the exemplary side view, there is a coolant oil gravity driven system 200 that includes a dampening element or connector 40 (which includes a pivot mechanism for swinging the nozzle 10) that can be made of rubber for dampening effect to absorb the energy of the external force caused by perturbation to enable the nozzle 10 to operate with a pivoting or back and forth operation and control the nozzle direction. A first gear 105 is connected to a counterweight 120 and exerts a downward force 130 and a second gear 110 that is coupled to the first gear 105 and a connecting rod 135 (or alternatively, a swing rod). The connecting rod 135 exerts a clockwise torque force to the nozzle 10 coupled to the connecting rod 135 that directs the flow of coolant oil over the hot surface of the electric motor.

[0042] Figure 3A 、 Figure 3B and Figure 3C Exemplary figures are shown of the application of a counterweight in response to different external forces caused by vehicle operation for achieving a flow distribution of coolant oil via a nozzle over the outer surface of an electric motor, according to exemplary embodiments. In Figure 3A the first gear 105 and the second gear 110 are in a relaxed position that does not exert a clockwise or counter clockwise torque on the nozzle 10 to cause any directional change to a forward or backward position. That is, the nozzle 10 is positioned in a vertical position to direct and distribute the coolant oil at a target area on the surface 20 without any counterweight force to counteract any external force caused by acceleration or road slope. The counterweight (dip plate) 120 directs a vertical force downward and there is no lateral force directed through the connecting rod 125 to position the target area and the target area in this neutral position is below the nozzle 10 and the coolant oil is directed directly, directionally changed to the surface 20 of the electric motor.

[0043] In Figure 3B the exemplary scenario of a tilted road or a road with a slope, the counterweight 120 is pointing downward, the exemplary directional arrows indicate the net force. In the exemplary embodiment, the first gear 105 exerts a (clockwise) torque 107 and a (counter clockwise) torque 112 (via the second gear 110) is exerted to the connecting rod 135 to cause the nozzle to direct the flow 75 of coolant oil from the initial nozzle position 122 to a new nozzle position 127 and distribute the coolant oil on the target area of the surface 20, which is an outer surface. In this case, the clockwise torque 107 of the first gear 105 created by the counterweight 120 is responsive to the lateral force to direct an opposite lateral force 141 to the nozzle 10 via the connecting rod 135 to change the nozzle direction.

[0044] In Figure 3CIn an exemplary scenario in which the vehicle is moving at a turn motion path, the first gear 105 exerts (counter-clockwise) torque 107 and (clockwise) torque 111 is exerted to the link 135 via the second gear 110 to cause the nozzle to direct the oil coolant flow 153 from the initial nozzle position 151 to the new nozzle position 142 and distribute the coolant oil over the target area of the surface 20. In this case, the counter-clockwise rotation torque 107 of the first gear is generated by the counterweight 120 in response to the sensed lateral force to direct the opposite lateral force 145 to the nozzle 10 via the link 135 to change the nozzle direction.

[0045] Figure 4A 、 Figure 4B and Figure 4C shows a side view schematic of a gravity driven oil coolant system according to an exemplary embodiment, in which the end turn winding flows past the stator of the electric motor; and

[0046] Figure 4A shows a side view of an electric motor with a gravity driven oil coolant system including the nozzle 10, the end turn winding 405, the surface 20, and the directed coolant oil flow 30. In this case, the end turn is where a conductor (winding) turns around a connection to another straight section. The majority of the cooling from the oil coolant flow occurs on the end turn because it is the only area exposed to the oil coolant via the nozzle 10. Figure 4B shows another side of the electric motor including the stator 410, the nozzle 10, and the end turn winding 405. Finally, Figure 4C includes the stator 410, the end turn winding 405, and the coolant oil flow 30 over the exposed end turn (i.e., the target area).

[0047] Figure 5 shows an exemplary flowchart of implementing counterweight torque in response to different external forces caused by vehicle operation for implementing the flow distribution of coolant oil via the nozzle over the outer surface of the electric motor according to an exemplary embodiment. In Figure 5 the flowchart, at step 510, the counterweight senses an external force disturbance that causes the coolant oil flow to move away from the target area and prevents the uniform distribution of the coolant oil over the end turn winding of the stator of the electric motor. The sensed external forces include acceleration and forces from road grade changes.

[0048] In response to the sensed external force, at step 520, the gravity driven mechanism is passively actuated via a counterweight coupled to a set of gears. The set of gears includes a first gear that applies a torque (e.g., clockwise torque) and a second gear that applies a different torque (e.g., counterclockwise torque). At step 530, the nozzle direction is repositioned to evenly distribute the coolant oil over the outer surface of the end turns of the electric motor, which is directed to the nozzle stream. At step 540, the nozzle direction is switched or pivoted across the exposed surface of the electric motor to effectively direct the coolant oil onto the exposed surface or evenly distribute the coolant oil over the exposed surface.

[0049] In an example embodiment, the nozzle is connected to a rubber connector that exhibits a dampening effect to lateral forces that cause the nozzle to sway. Further, the nozzle exhibits a swaying motion in response to external forces encountered by the vehicle motion to distribute the coolant oil over the outer surface of the electric motor. The external forces are a result of road grade and vehicle acceleration. A counterweight connected to the nozzle through a set of gears provides opposition to the external forces to cause the nozzle to sway to evenly direct and distribute the coolant oil over the outer surface of the electric motor. The rubber connector includes a pivot mechanism to enable the nozzle to sway in opposite directions by responding to the external forces through the torque applied from the counterweight. The set of gears provides counterclockwise and clockwise torque in response to the external forces to cause the nozzle to sway such that the coolant oil is evenly distributed over the entire outer surface of the electric motor.

[0050] It should be understood that Figure 5 the processes outlined in the figures can include any number of additional or Figure 5 the tasks shown in the figures need not be performed in the order indicated, Figure 5 the processes outlined in the figures can be incorporated into a more Figure 5 can be omitted from the embodiments of the processes described Figure 5 one or more of the tasks shown in the figures.

[0051] The foregoing detailed description has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the subject matter's embodiments to the precise form disclosed. As utilized herein the term "exemplary" means "serving as an example, instance, or illustration." Any implementation described herein as exemplary is not necessarily to be construed as preferred or advantageous over other implementations. Furthermore, the present subject matter is not intended to be limited to the particular forms shown, but on the contrary, it is intended to cover all modifications, equivalents, and alternatives falling within the scope of the appended claims.

[0052] While at least one exemplary embodiment has been presented in the foregoing detailed description of the application, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or embodiments are only examples, and are not intended to limit the scope, applicability or configuration of the 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 or embodiments. It should be understood that various changes can be made in the function and arrangement of elements without departing from the scope of the disclosure as set forth in the appended claims and their legal equivalents.

[0053] It should be understood that various changes can be made to the function and arrangement of elements without departing from the scope of the disclosure as set forth in the appended claims and their legal equivalents.

Claims

1. A system for providing gravity-driven distribution of coolant oil flow in a device, comprising: A nozzle for guiding a flow of coolant oil on the outer surface of an electric motor, wherein the flow of coolant oil is caused by gravity. A connector, attached to the nozzle, the connector enabling the nozzle to oscillate in response to external forces encountered during operation of the device, and distributing coolant oil onto the outer surface of the electric motor; and A counterweight, attached to the nozzle, provides resistance to external forces encountered during operation, causing the nozzle to oscillate in a manner that allows the coolant oil to be evenly distributed on the outer surface of the electric motor.

2. The system according to claim 1, further comprising: The nozzle is coupled to a connector that includes a pivot to enable the nozzle to oscillate in the opposite direction in response to external forces encountered during operation by a torque applied from the counterweight.

3. The system according to claim 2, further comprising: The counterweight is connected to a set of gears that respond to the external force by providing counterclockwise and clockwise torques to cause the nozzle to oscillate in a manner that allows the coolant oil to be evenly distributed on the outer surface of the electric motor.

4. The system according to claim 3, further comprising: The outer surface of the electric motor includes the stator winding end turns, wherein coolant oil is uniformly distributed on the end turns by the oscillation of nozzles partially controlled by a counterweight.

5. The system according to claim 4, further comprising: The counterweight includes a passive device that senses the movement of the device and responds to external forces by providing counter-clockwise and clockwise torques to cause the nozzle to oscillate in a manner that allows coolant oil to be evenly distributed on the outer surface of the electric motor.

6. The system according to claim 5, further comprising: A connecting rod connects the set of gears to the counterweight to reverse the direction of the nozzle oscillation in response to an external force on the nozzle generated by the operation.

7. The system according to claim 6, wherein, The set of gears includes a first gear and a second gear. The first gear is coupled to the counterweight and provides a counterclockwise torque. The second gear is coupled to the first gear and the connecting rod and provides a clockwise torque drive to counteract the external force causing the nozzle to oscillate and to receive a reverse force.

8. The system of claim 7, wherein the connector comprises a rubber connector.

9. A method for uniformly distributing coolant oil on the outer surface of an electric motor of a device, comprising: Gravity is used to guide the flow of coolant oil through nozzles on the outer surface of the electric motor. The nozzle is connected to a rubber connector that allows the nozzle to oscillate in response to external forces encountered by the movement of the device and to dispense coolant oil onto the outer surface of the electric motor, wherein the external forces are generated by gradients and device acceleration. as well as A counterweight is attached to the nozzle to provide resistance to the external force, causing the nozzle to oscillate in a manner that allows the coolant oil to be evenly distributed on the outer surface of the electric motor.

10. The method of claim 9, further comprising: in, The connector includes a pivot mechanism to enable the nozzle to oscillate in the opposite direction in response to an external force through a torque applied from the counterweight; as well as The counterweight is connected to a set of gears that respond to the external force by providing counterclockwise and clockwise torques to cause the nozzle to oscillate in a manner that allows the coolant oil to be evenly distributed on the outer surface of the electric motor.

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