Cooling tube with turbulence and spin generating features

Abstract

An example cooling tube has a hollow cylindrical body having a first portion and a second portion, opposite the first portion. In examples, the cooling tube can include one or more turbulence generating indentations formed in the second portion and configured to reshape an interior surface of the cooling tube to increase fluid turbulence. In examples, the cooling tube can include one or more spin generating indentations formed in the second portion as helical indentations that reshape the interior surface of the hollow cylindrical body to cause fluid to swirl.

Description

Cooling Tube with Turbulence and Spin Generating FeaturesCROSS REFERENCE TO RELATED APPLICATION

[0001] The present application claims priority to U.S. Provisional Patent Application No.63 / 610,587, filed on December 15, 2023, the entire contents of which are herein incorporated by reference as if fully set forth in this description.TECHNICAL FIELD

[0002] The present disclosure relates to methods and features for improving heat transfer in tubing. More particularly, the present disclosure relates to features that are pressed into the tube surface to reshape the inner tube surface. Such features promote turbulence and / or spinning of the fluid. Both turbulence and spinning of the fluid promote mixing, and improve heat transfer between the tube and the fluid. Further, the features enhance heat transfer for laminar, turbulent, and mixed flow regimes.BACKGROUND

[0003] It is common to use flowing liquid in tubes to transfer heat from a system. For example, a liquid (typically a water / glycol mixture, water, oil, or other coolants) flowing through copper or aluminum tubes disposed through a stator of an electric motor is used to cool the electric motor. In examples, the tubing could be used to cool or heat an electric motor, motor drivers, or other devices requiring thermal control.

[0004] A cooling tube typically has a round cross section. This style of tubing is readily accessible and cost effective. The tubing can be formed or bent into many configurations, but generally the cross section remains substantially circular.

[0005] However, tubes with circular cross sections might not provide optimized heat transfer. It may thus be desirable to modify the cooling tube with features that enhance heat transfer. It may further be desirable to have such features enhance heat transfer regardless of whether the flow is laminar, turbulent, or mixed. It is with respect to these and other considerations that the disclosure made herein is presented.SUMMARY

[0006] The present disclosure describes implementations that relate to a cooling tube with turbulence and spin generating features.

[0007] In a first example implementation, the present disclosure describes a cooling tube. The cooling tube includes: a hollow cylindrical body having (i) a first portion configured to be disposed in a semi-circular channel, and (ii) a second portion, opposite the first portion; a turbulence generating indentation formed in the second portion at an end of the hollow cylindrical body, wherein the turbulence generating indentation reshapes an interior surface of the hollow cylindrical body to cause back flow and increase fluid turbulence; and a plurality of spin generating indentations formed in the second portion as helical indentations, wherein the plurality of spin generating indentations reshape the interior surface of the hollow cylindrical body to cause fluid to swirl.

[0008] In a second example implementation, the present disclosure describes an electric motor. The electric motor includes: a stator having a lamination stack that includes a semi-circular channel; and the cooling tube of the first example implementation disposed in the semi-circular channel.

[0009] In a third example implementation, the present disclosure describes a method of forming the cooling tube of the first example implementation and / or the electric motor of the second example implementation.

[0010] The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, implementations, and features described above, further aspects, implementations, and features will become apparent by reference to the figures and the following detailed description.BRIEF DESCRIPTION OF THE FIGURES

[0011] The novel features believed characteristic of the illustrative examples are set forth in the appended claims. The illustrative examples, however, as well as a preferred mode of use, further objectives and descriptions thereof, will best be understood by reference to the following detailed description of an illustrative example of the present disclosure when read in conjunction with the accompanying Figures.

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

[0013] Figure 2 illustrates a perspective view of a lamination stack of a stator of the electric motor of Figure 1, according to an example implementation.

[0014] Figure 3A illustrates a perspective view of a cooling tube, according to an example implementation.

[0015] Figure 3B illustrates a top view of the cooling tube of Figure 3A, according to an example implementation

[0016] Figure 4A illustrates a perspective view of a cooling tube having turbulence generating indentations, according to an example implementation.

[0017] Figure 4B illustrates a top view of the cooling tube of Figure 4A, according to an example implementation.

[0018] Figure 4C illustrates an enlarged top view of the cooling tube of Figure 4B, according to an example implementation.

[0019] Figure 5A illustrates a perspective view of a cooling tube having spin generating indentations, according to an example implementation.

[0020] Figure 5B illustrates a top view of the cooling tube of Figure 5A, according to an example implementation.

[0021] Figure 5C illustrates an enlarged top view of the cooling tube of Figure 5B, according to an example implementation.

[0022] Figure 6A illustrates a perspective view of a cooling tube having turbulence generating indentations and spin generating indentations, according to an example implementation.

[0023] Figure 6B illustrates a top view of the cooling tube of Figure 6A, according to an example implementation.

[0024] Figure 6C illustrates an enlarged partial perspective view of the cooling tube of Figure 6A, according to an example implementation.

[0025] Figure 6D illustrates an enlarged top view of the cooling tube of Figure 6B, according to an example implementation.

[0026] Figure 6E illustrates a perspective cross-sectional view of the cooling tube of Figures 6A-6D, according to an example implementation.

[0027] Figure 7A illustrates a perspective view of a cooling tube disposed in a segment of a lamination stack, according to an example implementation.

[0028] Figure 7B illustrates a top view of the cooling tube and the segment of Figure 7A, according to an example implementation.

[0029] Figure 7C illustrates a cross-sectional side view of the cooling tube and the segment of Figures 7A-7B, according to an example implementation.

[0030] Figure 8 is a flowchart of a method of forming a cooling tube and / or an electric motor, according to an example implementation.DETAILED DESCRIPTION

[0031] Within examples, disclosed herein are cooling tubes where their cross section is modified by exterior features pressed into the outside of the cooling tubes, reshaping the inside of the wall of the cooling tube and improving heat transfer (e.g., cooling) to a fluid flowing through the cooling tube. The terms “fluid” and “coolant” are used interchangeably herein.

[0032] Enhanced heat transfer occurs when flow through a cooling tube is turbulent. However, to minimize back pressure on the coolant system in some applications, the fluid flow rate can vary between being laminar and turbulent flow. The disclosed cooling tubes enhance heat transfer when flow is laminar (e.g., when using low flow rates) by spinning the fluid in the cooling tube. This can be accomplished by pressing angled or helical features on a portion of the outside of the cooling tube.

[0033] At higher (turbulent) flow rates, the disclosed cooling tubes enhance heat transfer by including turbulence and / or back flow features. These features can be placed at or near the inlet region where a substantial portion of the thermal transfer may take place. In some examples, placing several of these features along the cooling tube further enhances heat transfer.

[0034] In examples, for mixed or uncertain flow rates (e.g., sometimes laminar, sometimes turbulent), the disclosed cooling tubes combine the spin generating features with the turbulence generating feature. With this configuration, heat transfer (e.g., cooling) is enhanced for both laminar and turbulent flow rates.

[0035] Although the cooling tubes disclosed herein are described in the context of cooling an electric motor, the features and configurations described herein can be used for other coolingapplications. For example, the disclosed cooling tubes can be used to cool or heat electric motor electronics drivers, or other devices requiring thermal controls.

[0036] An electric motor is an electrical machine that converts electrical energy into mechanical energy. Most electric motors operate through the interaction between the motor’s magnetic field and electric current in wire windings to generate force in the form of rotation of a shaft. Electric motors can be powered by direct current (DC) sources, such as batteries or motor vehicles or rectifiers, or by alternating current (AC) sources, such as a power grid, inverters, or electrical generators.

[0037] The torque and power generated at the shaft of the motor are limited by how much current or electric power is input through the wire windings. Increasing current beyond a certain limit can increase the temperature of the wire windings and cause damage to the wires and the electric motor. It may thus be desirable to have an electric motor with enhanced thermal characteristics to enable improved heat transfer from the wire windings, thereby reducing the temperature of the wire windings for a given current input, preventing damage to the motor, and enabling an increase in the current limit

[0038] Figure 1 illustrates a partial perspective view of an electric motor 100, according to an example implementation. A housing of the electric motor 100 is not shown to reveal internal components of the electric motor 100.

[0039] The electric motor 100 includes a stator 102, which is configured to generate a magnetic field. Particularly, the stator 102 includes wire windings such as wire winding 104 (a bundle of wires or coil) wrapped about a lamination stack 106, and when electric current is provided through the wire windings, a magnetic field is generated.

[0040] The electric motor 100 further includes a rotor 108. The stator 102 can have an open annular space in which the rotor 108 is disposed. The rotor 108 can have magnets, such as magnet 109, mounted thereto that can interact with the magnetic field generated by the stator 102, causing the rotor 108 to rotate and produce torque.

[0041] Figure 2 illustrates a perspective view of the lamination stack 106 of the stator 102, according to an example implementation. As illustrated in Figure 2, the lamination stack 106 is generally donut-shaped and has an open annular space 200 in which the rotor 108 can be positioned.

[0042] The lamination stack 106 is formed of laminated electrical steel sheets. Lamination is the technique / process of manufacturing a material in multiple layers, so that the composite material achieves improved strength, stability, sound insulation, appearance or other desirable electrical properties.

[0043] The lamination stack 106 can be made of silicon steel, also known as electrical steel, which comprises steel with silicon added to it. Adding silicon to steel increases its electrical resistance, improves the ability of magnetic fields to penetrate it, and reduces the steel’s hysteresis loss. The lamination stack 106 represents the core of the stator 102, and the lamination stack 106 is laminated and insulated in order to reduce induced circulating currents and associated heat as electric current is modulated through the wire windings of the stator 102.

[0044] In an example, the lamination stack 106 can be made as a single piece or single component that is not segmented. For instance, the lamination stack 106 can have poles or teeth similar to a gear, and the slots or spaces between the teeth can be configured to receive wires therethrough.

[0045] In another example, as shown in Figure 2, the lamination stack 106 includes multiple segments, such as segment 202, segment 204, and segment 206, disposed adjacent to teach other in a circular array and interface with each. The segments are generally formed or shaped as I-beams that have C-shaped side channels or slots on each side thereof. Thus, when two adjacent segments interface with each other, a slot is formed therebetween and includes the C-shaped channels or respective slots of the two adjacent segments. For example, a slot 208 is formed between the segment 202 and the segment 204, and a slot 210 is formed between the segment 204 and the segment 206. Wires are wound through the slots of the lamination stack 106 in wire bundles or coils to form the wire windings such as the wire winding 104 shown in Figure 1.

[0046] Although the description below refers to a multiple segment construction of the lamination stack 106, it should be understood that similar description applies to a lamination stack having unitary construction and made as a single component that is not segmented.

[0047] As electric current is provided through the wire windings of the stator 102, the temperature of the wires increases and heat is generated. The heat can be referred to as winding losses. The rising temperature of the wires can cause damage and limit performance of the electric motor 100.

[0048] In examples, to cool the lamination stack 106 and the wires disposed therein, the lamination stack 106 can be liquid-cooled. As shown in Figure 2, each of the segments can have channels disposed therein that are semi-circular in shape. For instance, the segment 202 has a semi-circular channel 212 that is disposed or extends longitudinally along an exterior peripheral surface of the segment 202. This way, multiple semi-circular channels are formed in a circular array around a periphery of the lamination stack 106.

[0049] Referring back to Figure 1, cooling tubes, such as a cooling tube 110, can be disposed through the semi-circular channels of the lamination stack 106. One more cooling tubes or cooling tube sections or segments can be used such that the cooling tubes loop and bend to traverse all the semi-circular channels of the lamination stack 106.

[0050] As shown, a straight portion 112 of the cooling tube 110 is disposed in the semi-circular channel 212 of the segment 202 of the lamination stack 106. Cooling fluid flows through the cooling tube 110, thereby absorbing some of the heat generated by the wires, cooling the lamination stack 106 and the wire windings disposed therein.

[0051] Figure 3 A illustrates a perspective view of the cooling tube 110, and Figure 3B illustrates a top view of the cooling tube 110, according to an example implementation. The cooling tube 110 has or is configured as a hollow cylindrical body 301 (e.g., a cylindrical shell) with a generally circular cross section, and can be made of a metallic material (e.g., copper or aluminum) that is a good thermal conductor.

[0052] The hollow cylindrical body 301 has a first portion 300 (e.g., inward bottom half of the cooling tube 110) that is received within, and interacts with, the semi-circular channel 212 of the lamination stack 106. The hollow cylindrical body 301 further has a second portion 302 (e.g., outward or top half of the cooling tube 110), opposite the first portion 300. As such, the second portion 302 is not disposed within the semi-circular channel 212 and might not contact the lamination stack 106. Rather, the second portion 302 is configured to be exposed outward from the lamination stack 106 to an external environment of the stator 102.

[0053] When the cooling tube 110 is pressed or inserted into the semi-circular channel 212, the sides of the cooling tube 110 may flatten. Thus, the cooling tube 110 may become somewhat “D” shaped. However, the inner cross section may remain substantially circular.

[0054] When coolant flows through the cooling tube 110 at high flow rates (high Reynolds number flow), the coolant flow may be turbulent. Conversely, when coolant flows through the cooling tube 110 at low flow rates (low Reynolds number flow), the coolant flow may be laminar. It may be desirable to add features to the cooling tube 110 to enhance heat transfer based on the type of flow (laminar, turbulent, or a mix of laminar and turbulent flow).

[0055] Such features can be added to the second portion 302 (e.g., top half) of the cooling tube 110 that is exposed outward from the lamination stack 106. By adding the features to the second portion 302, the thermal contact resistance of the first portion 300 (e.g., bottom half) that is in contact with the lamination stack 106 is not affected.

[0056] Figure 4A illustrates a perspective view of a cooling tube 400 having turbulence generating indentations 402, Figure 4B illustrates a top view of the cooling tube 400, and Figure 4C illustrates an enlarged top view of the cooling tube 400, according to an example implementation. Particularly, Figure 4C depicts an enlarged view of a section of the cooling tube 400 as labelled in Figure 4B.

[0057] The cooling tube 400 represents the cooling tube 110 after the turbulence generating indentations 402 have been pressed or formed in the cooling tube. The turbulence generating indentations 402 are added to the second portion 302 (e.g., top half) of the cooling tube 400 that is exposed outward from (e.g., is not in contact with) the lamination stack 106 of the stator 102.

[0058] The turbulence generating indentations 402 are pressed or formed into the second portion 302 such that an inner surface of the cooling tube 400 protrudes into the flow path within the cooling tube 400 to cause or generate turbulence in the coolant flow. In other words, the interior surface of the cooling tube 400 is reshaped due to the turbulence generating indentations 402, thereby increasing turbulence. Particularly, the protrusions operate as back flow features thatmay increase turbulence. The protrusions also increase surface area of the cooling tube 400 through which heat is transferred.

[0059] In an example, the turbulence generating indentations 402 can each have a substantially dihedral shape. Particularly, referring to Figures 4A, 4C, a turbulence generating indentation 404 of the turbulence generating indentations 402 can have a depressed central portion 406, and two upward inclining portions, an inclined portion 408 and an inclined portion 410, that intersect at the depressed central portion 406. The inclined portions 408, 410 each form an angle with the depressed central portion 406. In examples, the inclined portions 408, 410 can be flat or planar, but angle upward from the depressed central portion 406.

[0060] In examples, the turbulence generating indentations 402 are placed at or near the inlet region where substantial thermal transfer takes place. For example, one or more turbulence generating indentations can be placed at each end of the straight portion of the cooling tube 400. In other examples, several turbulence generating indentations are placed along a length of the cooling tube 400 to increase the heat transfer as shown in Figures 4A-4C.

[0061] In some examples, the turbulence generating indentations 402 are formed along only a portion of the cooling tube 400. For instance, the turbulence generating indentations 402 can be disposed along one third of the cooling tube 400 (e.g., along a part of the straight portion 112 of the cooling tube 110), while other parts might not include the turbulence generating indentations 402.

[0062] When the flow is laminar, other types of features may be pressed onto the second portion 302 of the cooling tube 110. As an example, for laminar flow rates, heat transfer can be improved by spinning or swirling the fluid in the cooling tube 110.

[0063] Figure 5A illustrates a perspective view of a cooling tube 500 having spin generating indentations 502, Figure 5B illustrates a top view of the cooling tube 500, and Figure 5C illustrates an enlarged top view of the cooling tube 500, according to an example implementation. Particularly, Figure 5C depicts an enlarged view of a section of the cooling tube 500 as labelled in Figure 5B.

[0064] The cooling tube 500 represents the cooling tube 110 after the spin generating indentations 502 have been pressed or formed in the cooling tube. The spin generating indentations 502 (such as spin generating indentation 504) are added to the second portion 302 (e.g., top half) of the cooling tube 500 that is exposed outward from (e.g., not in contact with) the lamination stack 106 of the stator 102.

[0065] The spin generating indentations 502 can include angled or helical indentations that are pressed or formed into the second portion 302 of the hollow cylindrical body 301. As such, the interior surface of the cooling tube 500 is reshaped such that it protrudes at respective angles into the flow path within the cooling tube 500 to spin the fluid (e.g., cause the fluid to swirl) as fluid flows through the cooling tube 500.

[0066] As depicted in Figures 5A-5B, several spin generating indentations are placed along a length of the cooling tube 500 to increase the heat transfer. The helical angle shown in Figure 5C is depicted as approximately 16 degree as an example for illustration only, and is not meant to be limiting. The term “approximately” is used herein to indicate an angle within a threshold from the 16 degree angle. For example, the angle can be between 15 and 17 degrees. In another example, the angle can between 14 and 18 degrees.

[0067] Although turbulent flow (or a mix between turbulent and laminar flow) can enhance heat transfer and cooling efficiency, in some cases smaller or laminar low flow rates are used tominimize back pressure on the coolant system. As such, during operation of the electric motor 100, flow can vary between laminar and turbulent. It may thus be desirable in some cases to add features to the cooling tube 110 to enhance heat transfer during both laminar and turbulent flows, or during a mixed flow regime.

[0068] Figure 6A illustrates a perspective view of a cooling tube 600 having turbulence generating indentations and spin generating indentations, Figure 6B illustrates a top view of the cooling tube 600, Figure 6C illustrates an enlarged partial perspective view of the cooling tube 600, Figure 6D illustrates an enlarged top view of the cooling tube 600, and Figure 6E illustrates a perspective cross-sectional view of the cooling tube 600, according to an example implementation. Particularly, Figure 6D depicts an enlarged view of a section of the cooling tube 400 as labelled in Figure 6B.

[0069] The cooling tube 600 represents the cooling tube 110 after the turbulence generating indentations and spin generating features have been added to the second portion 302 that is not in contact with the lamination stack 106.

[0070] For mixed or uncertain flow rates, it may be desirable to combine the spin generating features (e.g., helical features) with the turbulence generating features. With this configuration, enhanced heat transfer may be achieved for both laminar and turbulent flow rates.

[0071] Particularly, the cooling tube 600 includes turbulence generating indentations at both ends of the cooling tube 600 where the fluid inlets are in both directions. For example, a first turbulence generating indentation 602 is formed at a first end of the hollow cylindrical body of cooling tube 600, while a second turbulence generating indentation 604 is placed at the other or second end, opposite the first end.

[0072] In an example, the turbulence generating indentations 602, 604 can be configured to have dihedral shapes similar to the turbulence generating indentation 404 described above. The turbulence generating indentations 602, 604 are pressed or formed into the second portion 302, such that an inner surface of the cooling tube 600 protrudes into the flow path within the cooling tube 600 to cause or generate turbulence in the flow.

[0073] The cooling tube 600 further includes a plurality of spin generating indentations 606 formed along a length of the cooling tube 600, and axially interposed between the turbulence generating indentations 602, 604. The spin generating indentations 606 are similar to the spin generating indentations 502 described above, and can be configured as helical or angled indentations that are pressed into the second portion 302, such that an inner surface of the cooling tube 600 protrudes at respective angles into the flow path within the cooling tube 600 to spin the fluid (e.g., cause the fluid to swirl) as fluid flows through the cooling tube 600.

[0074] With this configuration, by placing the turbulence generating indentations 602, 604 on both ends of the cooling tube 600, while including the spin generating indentations 606 therebetween, heat transfer is enhanced regardless of whether coolant flow is laminar or turbulent. Further, the turbulence and spin generating indentations provide a large surface for heat transfer on the inside of the cooling tube 600, further enhancing the heat transfer capability of the cooling tube 600.

[0075] Computational Fluid Dynamics models estimate that using the spin and turbulence generating indentation features provides approximately 3 to 5 times improvement in the ability of a cooling tube to transfer heat into the coolant compared to a cooling tube without the indentations. It is estimated that in practice the improvement can be in the 1.5 to 3 times range improvement over a cooling tube without the features.

[0076] Advantageously, the tool that presses the cooling tubes (any of the cooling tubes described above) into the semi-circular channels (e.g., the semi-circular channel 212) of the stator 102 can also be used to press the spin and / or turbulence generating indentations. This way, manufacturing efficiency may be enhanced, and cost may be reduced, while enhancing cooling efficiency.

[0077] Figure 7A illustrates a perspective view of the cooling tube 600 disposed in the segment 202 of the lamination stack 106, Figure 7B illustrates a top view of the cooling tube 600 disposed in the segment 202 of the lamination stack 106, and Figure 7C illustrates a cross-sectional side view of the cooling tube 600 disposed in the segment 202 of the lamination stack 106, according to an example implementation. Although Figures 7A-7C are described using the cooling tube 600, the cooling tubes 400, 500 could alternatively be used.

[0078] Most of the heat transfer from the segment 202 to the cooling tube 600 (through which coolant flows and absorbs heat) takes place at the first portion 300 where the cooling tube 600 is in contact with the surface of the segment 202 of the lamination stack 106. The second portion 302 (which is not in contact with the surface of the segment 202) of the coolant tube 600 has the flow modifying features / indentations such as the turbulence generating indentations 602, 604 and the spin generating indentations 606.

[0079] This configuration advantageously avoids forming the flow modifying features in the first portion 300 (the contact area) to avoid reducing the contact surface area between the cooling tube 600 and the segment 202, and thus avoids reducing the heat transfer or cooling efficiency. Rather, the first portion 300 remains smooth for enhanced thermal contact with the segment 202.

[0080] Figure 8 is a flowchart of a method 700 of forming a cooling tube and / or an electric motor, according to an example implementation. The method 700 can be used to form any of thecooling tubes 110, 400, 500, 600 described above or form / assemble the electric motor 100, for example. At least some of the operations of the method 700 can be performed automatically, e.g., via a machine or robot.

[0081] The method 700 may include one or more operations, or actions as illustrated by one or more of blocks 702-710. Although the blocks are illustrated in a sequential order, these blocks may also be performed in parallel, and / or in a different order than those described herein. Also, the various blocks may be combined into fewer blocks, divided into additional blocks, and / or removed based upon the desired implementation. It should be understood that for this and other processes and methods disclosed herein, flowcharts show functionality and operation of one possible implementation of present examples. Alternative implementations are included within the scope of the examples of the present disclosure in which functions may be executed out of order from that shown or discussed, including substantially concurrent or in reverse order, depending on the functionality involved, as would be understood by those reasonably skilled in the art.

[0082] At block 702, the method 700 includes providing the stator 102 of the electric motor 100, wherein the stator 102 has the semi-circular channel 212.

[0083] At block 704, the method 700 includes providing a cooling tube (e.g., any of the cooling tubes 110, 400, 500, 600).

[0084] The term “providing” as used herein, and for example with regard to the stator 102 or the cooling tube includes any action to make the stator 102 or cooling tube available for use, such as bringing the stator 102 or cooling tube to an apparatus or to a work environment for further processing (e.g., mounting other components, forming features such as cooling channels in the stator or the turbulence and spin generating indentations in the cooling tube, etc.).

[0085] At block 706, the method 700 includes forming one or more turbulence generating indentations (e.g., the turbulence generating indentations 404, 602, 604) in the cooling tube.

[0086] At block 708, the method 700 includes forming one or more spin generating indentations (e.g., the spin generating indentations 502, 606) in the cooling tube.

[0087] At block 710, the method 700 includes inserting the cooling tube in the semi-circular channel such that (i) the first portion 300 of the cooling tube is disposed in the semi-circular channel 212 and contacts the stator 102, and (ii) the second portion 302, opposite the first portion 300, of the cooling tube is exposed to an external environment of the stator 102, wherein the one or more turbulence generating indentations and the one or more spin generating indentations are formed in the second portion 302 of the cooling tube, wherein the one or more turbulence generating indentations reshape an interior surface of the cooling tube to increase fluid turbulence, and wherein the one or more spin generating indentations reshape the interior surface of the cooling tube to cause fluid to swirl.

[0088] The method 700 can further include any other steps and operations described throughout herein.

[0089] The detailed description above describes various features and operations of the disclosed systems with reference to the accompanying figures. The illustrative implementations described herein are not meant to be limiting. Certain aspects of the disclosed systems can be arranged and combined in a wide variety of different configurations, all of which are contemplated herein.

[0090] Further, unless context suggests otherwise, the features illustrated in each of the figures may be used in combination with one another. Thus, the figures should be generally viewed ascomponent aspects of one or more overall implementations, with the understanding that not all illustrated features are necessary for each implementation.

[0091] Additionally, any enumeration of elements, blocks, or steps in this specification or the claims is for purposes of clarity. Thus, such enumeration should not be interpreted to require or imply that these elements, blocks, or steps adhere to a particular arrangement or are carried out in a particular order.

[0092] Further, devices or systems may be used or configured to perform actuators presented in the figures. In some instances, components of the devices and / or systems may be configured to perform the actuators such that the components are actually configured and structured (with hardware and / or software) to enable such performance. In other examples, components of the devices and / or systems may be arranged to be adapted to, capable of, or suited for performing the actuators, such as when operated in a specific manner.

[0093] By the term “substantially” it is meant that the recited characteristic, parameter, or value need not be achieved exactly, but that deviations or variations, including for example, tolerances, measurement error, measurement accuracy limitations and other factors known to those with skill in the art, may occur in amounts that do not preclude the effect the characteristic was intended to provide.

[0094] The arrangements described herein are for purposes of example only. As such, those skilled in the art will appreciate that other arrangements and other elements (e.g., machines, interfaces, operations, orders, and groupings of operations, etc.) can be used instead, and some elements may be omitted altogether according to the desired results. Further, many of the elements that are described are functional entities that may be implemented as discrete ordistributed components or in conjunction with other components, in any suitable combination and location.

[0095] While various aspects and implementations have been disclosed herein, other aspects and implementations will be apparent to those skilled in the art. The various aspects and implementations disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope being indicated by the following claims, along with the full scope of equivalents to which such claims are entitled. Also, the terminology used herein is for the purpose of describing particular implementations only, and is not intended to be limiting.

[0096] Embodiments of the present disclosure can thus relate to one of the enumerated example embodiments (EEEs) listed below.

[0097] EEE 1 is a cooling tube comprising: a hollow cylindrical body having (i) a first portion configured to be disposed in a semi-circular channel, and (ii) a second portion, opposite the first portion; a turbulence generating indentation formed in the second portion at an end of the hollow cylindrical body, wherein the turbulence generating indentation reshapes an interior surface of the hollow cylindrical body to cause back flow and increase fluid turbulence; and a plurality of spin generating indentations formed in the second portion as helical indentations, wherein the plurality of spin generating indentations reshape the interior surface of the hollow cylindrical body to cause fluid to swirl.

[0098] EEE 2 is the cooling tube of EEE 1, wherein the end of the hollow cylindrical body is a first end, wherein the turbulence generating indentation is a first turbulence generating indentation, and wherein the cooling tube further comprises: a second turbulence generating indentation formed in the second portion at a second end of the hollow cylindrical body, whereinthe second turbulence generating indentation reshapes the interior surface of the hollow cylindrical body to cause back flow and increase fluid turbulence.

[0099] EEE 3 is the cooling tube of EEE 2, wherein the plurality of spin generating indentations are disposed along a length of the cooling tube, axially interposed between the first turbulence generating indentation and the second turbulence generating indentation.

[0100] EEE 4 is the cooling tube of any of EEEs 1-3, wherein the turbulence generating indentation has a dihedral shape having a depressed central portion and two upward inclining portions that intersect at the depressed central portion.

[0101] EEE 5 is the cooling tube of any of EEEs 1-4, wherein the turbulence generating indentation is formed in at an inlet region of the hollow cylindrical body through which coolant enters the cooling tube.

[0102] EEE 6 is an electric motor comprising the cooling tube of any of EEEs 1-5. For example, the electric motor comprises: a stator having a lamination stack that includes a semicircular channel; a cooling tube having (i) a first portion disposed in the semi-circular channel, and (ii) a second portion, opposite the first portion, exposed from the lamination stack; one or more turbulence generating indentations formed in the second portion, wherein the one or more turbulence generating indentations reshape an interior surface of the cooling tube to increase fluid turbulence; and one or more spin generating indentations formed in the second portion as helical indentations, wherein the one or more spin generating indentations reshape the interior surface of the cooling tube to cause fluid to swirl.

[0103] EEE 7 is the electric motor of EEE 6, wherein at least one of the one or more turbulence generating indentations has a dihedral shape having a depressed central portion and two upward inclining portions that intersect at the depressed central portion.

[0104] EEE 8 is the electric motor of any of EEEs 6-7, wherein the one or more turbulence generating indentations comprises: a first turbulence generating indentation formed in the second portion at a first end of the cooling tube; and a second turbulence generating indentation formed in the second portion at a second end of the cooling tube.

[0105] EEE 9 is the electric motor of EEE 8, wherein the one or more spin generating indentations are axially interposed between the first turbulence generating indentation and the second turbulence generating indentation along a length of the cooling tube.

[0106] EEE 10 is the electric motor of any of EEEs 6-9, wherein the one or more turbulence generating indentations are formed in at an inlet region of the cooling tube through which coolant enters the cooling tube.

[0107] EEE 11 is the electric motor of any of EEEs 6-10, wherein the semi-circular channel is a first semi-circular channel, wherein the stator includes a second semi-circular channel, wherein a first cooling tube section of the cooling tube is disposed in the first semi-circular channel, wherein the first cooling tube section has the one or more turbulence generating indentations and the one or more spin generating indentations, wherein the cooling tube is looped, and a second cooling tube section is disposed through the second semi-circular channels.

[0108] EEE 12 is the electric motor of EEE 11, wherein the second cooling tube section comprises: one or more respective turbulence generating indentations; and one or more respective spin generating indentations.

[0109] EEE 13 is a method comprising: providing a stator of an electric motor, wherein the stator has a semi-circular channel; providing a cooling tube; forming one or more turbulence generating indentations in the cooling tube; forming one or more spin generating indentations in the cooling tube; and inserting the cooling tube in the semi-circular channel such that (i) a first portion of the cooling tube is disposed in the semi-circular channel and contacts the stator, and (ii) a second portion, opposite the first portion, of the cooling tube is exposed to an external environment of the stator, wherein the one or more turbulence generating indentations and the one or more spin generating indentations are formed in the second portion of the cooling tube, wherein the one or more turbulence generating indentations reshape an interior surface of the cooling tube to increase fluid turbulence, and wherein the one or more spin generating indentations reshape the interior surface of the cooling tube to cause fluid to swirl.

[0110] EEE 14 is the method of EEE 13, wherein forming the one or more turbulence generating indentations comprises: forming at least one of the one or more turbulence generating indentations to have a dihedral shape having a depressed central portion and two upward inclining portions that intersect at the depressed central portion.

[0111] EEE 15 is the method of any of EEEs 13-14, wherein forming the one or more turbulence generating indentations comprises: forming a first turbulence generating indentation at a first end of the cooling tube; and forming a second turbulence generating indentation at a second end of the cooling tube.

[0112] EEE 16 is the method of EEE 15, wherein forming the one or more spin generating indentations comprises: forming the one or more spin generating indentations to be axially interposed between the first turbulence generating indentation and the second turbulence generating indentation along a length of the cooling tube.

[0113] EEE 17 is the method of any of EEEs 13-16, wherein forming the one or more turbulence generating indentations comprises: forming the one or more turbulence generating indentation at an inlet region of the cooling tube through which coolant enters the cooling tube.

[0114] EEE 18 is the method of any of EEEs 13-17, wherein the semi-circular channel is a first semi-circular channel, wherein the stator includes a second semi-circular channel, wherein a first cooling tube section of the cooling tube is disposed in the first semi-circular channel, wherein the first cooling tube section has the one or more turbulence generating indentations and the one or more spin generating indentations, wherein the method further comprises: looping the cooling tube; and inserting a second cooling tube section of the cooling tube in the second semi-circular channels.

[0115] EEE 19 is the method of EEE 18, further comprising: forming one or more respective turbulence generating indentations in the second cooling tube section; and forming one or more respective spin generating indentations in the second cooling tube section.

[0116] EEE 20 is the method of any of EEEs 13-19, wherein forming the one or more spin generating indentations comprises: forming the one or more spin generating indentations as helical indentations having an helical angle between 14 and 18 degrees.

Claims

CLAIMSWhat is claimed is:

1. A cooling tube comprising:a hollow cylindrical body having (i) a first portion configured to be disposed in a semicircular channel, and (ii) a second portion, opposite the first portion;a turbulence generating indentation formed in the second portion at an end of the hollow cylindrical body, wherein the turbulence generating indentation reshapes an interior surface of the hollow cylindrical body to cause back flow and increase fluid turbulence; anda plurality of spin generating indentations formed in the second portion as helical indentations, wherein the plurality of spin generating indentations reshape the interior surface of the hollow cylindrical body to cause fluid to swirl.

2. The cooling tube of claim 1, wherein the end of the hollow cylindrical body is a first end, wherein the turbulence generating indentation is a first turbulence generating indentation, and wherein the cooling tube further comprises:a second turbulence generating indentation formed in the second portion at a second end of the hollow cylindrical body, wherein the second turbulence generating indentation reshapes the interior surface of the hollow cylindrical body to cause back flow and increase fluid turbulence.

3. The cooling tube of claim 2, wherein the plurality of spin generating indentations are disposed along a length of the cooling tube, axially interposed between the first turbulence generating indentation and the second turbulence generating indentation.

4. The cooling tube of claim 1, wherein the turbulence generating indentation has a dihedral shape having a depressed central portion and two upward inclining portions that intersect at the depressed central portion.

5. The cooling tube of claim 1, wherein the turbulence generating indentation is formed in at an inlet region of the hollow cylindrical body through which coolant enters the cooling tube.

6. An electric motor comprising:a stator having a lamination stack that includes a semi-circular channel;a cooling tube having (i) a first portion disposed in the semi-circular channel, and (ii) a second portion, opposite the first portion, exposed from the lamination stack;one or more turbulence generating indentations formed in the second portion, wherein the one or more turbulence generating indentations reshape an interior surface of the cooling tube to increase fluid turbulence; andone or more spin generating indentations formed in the second portion as helical indentations, wherein the one or more spin generating indentations reshape the interior surface of the cooling tube to cause fluid to swirl.

7. The electric motor of claim 6, wherein at least one of the one or more turbulence generating indentations has a dihedral shape having a depressed central portion and two upward inclining portions that intersect at the depressed central portion.

8. The electric motor of claim 6, wherein the one or more turbulence generating indentations comprises:a first turbulence generating indentation formed in the second portion at a first end of the cooling tube; anda second turbulence generating indentation formed in the second portion at a second end of the cooling tube.

9. The electric motor of claim 8, wherein the one or more spin generating indentations are axially interposed between the first turbulence generating indentation and the second turbulence generating indentation along a length of the cooling tube.

10. The electric motor of claim 6, wherein the one or more turbulence generating indentations are formed in at an inlet region of the cooling tube through which coolant enters the cooling tube.

11. The electric motor of claim 6, wherein the semi-circular channel is a first semicircular channel, wherein the stator includes a second semi-circular channel, wherein a first cooling tube section of the cooling tube is disposed in the first semi-circular channel, wherein the first cooling tube section has the one or more turbulence generating indentations and the one or more spin generating indentations, wherein the cooling tube is looped, and a second cooling tube section is disposed through the second semi-circular channels.

12. The electric motor of claim 11, wherein the second cooling tube section comprises:one or more respective turbulence generating indentations; andone or more respective spin generating indentations.

13. A method comprising:providing a stator of an electric motor, wherein the stator has a semi-circular channel; providing a cooling tube;forming one or more turbulence generating indentations in the cooling tube; forming one or more spin generating indentations in the cooling tube; andinserting the cooling tube in the semi-circular channel such that (i) a first portion of the cooling tube is disposed in the semi-circular channel and contacts the stator, and (ii) a second portion, opposite the first portion, of the cooling tube is exposed to an external environment of the stator, wherein the one or more turbulence generating indentations and the one or more spin generating indentations are formed in the second portion of the cooling tube, wherein the one or more turbulence generating indentations reshape an interior surface of the cooling tube to increase fluid turbulence, and wherein the one or more spin generating indentations reshape the interior surface of the cooling tube to cause fluid to swirl.

14. The method of claim 13, wherein forming the one or more turbulence generating indentations comprises:forming at least one of the one or more turbulence generating indentations to have a dihedral shape having a depressed central portion and two upward inclining portions that intersect at the depressed central portion.

15. The method of claim 13, wherein forming the one or more turbulence generating indentations comprises:forming a first turbulence generating indentation at a first end of the cooling tube; and forming a second turbulence generating indentation at a second end of the cooling tube.

16. The method of claim 15, wherein forming the one or more spin generating indentations comprises:forming the one or more spin generating indentations to be axially interposed between the first turbulence generating indentation and the second turbulence generating indentation along a length of the cooling tube.

17. The method of claim 13, wherein forming the one or more turbulence generating indentations comprises:forming the one or more turbulence generating indentation at an inlet region of the cooling tube through which coolant enters the cooling tube.

18. The method of claim 13, wherein the semi-circular channel is a first semi-circular channel, wherein the stator includes a second semi-circular channel, wherein a first cooling tube section of the cooling tube is disposed in the first semi-circular channel, wherein the first coolingtube section has the one or more turbulence generating indentations and the one or more spin generating indentations, wherein the method further comprises:looping the cooling tube; andinserting a second cooling tube section of the cooling tube in the second semi-circular channels.

19. The method of claim 18, further comprising:forming one or more respective turbulence generating indentations in the second cooling tube section; andforming one or more respective spin generating indentations in the second cooling tube section.

20. The method of claim 13, wherein forming the one or more spin generating indentations comprises:forming the one or more spin generating indentations as helical indentations having an helical angle between 14 and 18 degrees.

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