CN113054802A

CN113054802A - Electric motor with conformal heat pipe assembly

Info

Publication number: CN113054802A
Application number: CN202011547010.9A
Authority: CN
Inventors: N·B·霍斯; K·博拉; B·M·拉什; 尹卫军; A·T·克罗斯; C·布拉萨
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 2019-12-26
Filing date: 2020-12-24
Publication date: 2021-06-29

Abstract

A heat pipe assembly includes a wall having a porous wicking liner, an insulating layer coupled to at least one wall, and an interior chamber sealed by the wall. The liner maintains the working fluid in the inner chamber in a liquid phase. The insulating layer is directly against the electrically conductive member of the electromagnetic power conversion device such that heat from the electrically conductive member vaporizes the working fluid in the porous wicking liner of at least one wall and the working fluid condenses at or within the porous wicking liner of at least one other wall to cool the electrically conductive member of the electromagnetic power conversion device. The components may be placed in direct contact with the device as it operates and/or experiences time-varying magnetic fields that cause the device to operate.

Description

Electric motor with conformal heat pipe assembly

Cross reference to related applications

This application is a continuation-in-part application of U.S. patent application No.16/203,161 filed on 28.11.2018, and U.S. patent application No.16/203,161 claims priority to U.S. provisional application No.62/670,460 filed on 11.5.2018. The entire disclosures of these applications are incorporated herein by reference.

Technical Field

The subject matter described herein relates to electric motors having Heat Pipes (HP).

Background

Electromagnetic (EM) power conversion devices generate heat during operation due to joule heating. Examples of these types of devices include electrical machines, such as motors and generators, inductors and transformers. The effectiveness of thermal management methods may limit the power density, power per unit volume, and/or power per unit weight that can be achieved in these devices. Improved thermal management methods may allow for increased amounts of current in the conductors of the device without exceeding safe operating temperature limits. Increasing the amount of current that can be conducted in the conductors of a device may allow for an increase in the power density of the device.

One method of managing the heat generated in the device is a heat pipe. Some known heat pipes are made of an electrically conductive material such as copper. The conductive material generates additional heat when a high frequency electromagnetic field is present. As a result, precisely such heat pipes that should operate to carry heat away from the device (e.g., away from the device's conductive windings or coils) generate additional heat due to changes in the electromagnetic field near the heat pipe, resulting in reduced power conversion efficiency in addition to potentially increasing temperature.

Disclosure of Invention

In one embodiment, a heat pipe assembly includes a plurality of connected walls having a porous wicking liner along the walls, an insulating layer coupled to at least one wall on a side of the at least one wall opposite the porous wicking liner of the at least one wall, and an interior chamber disposed within and sealed by the walls. The porous wicking liner of the wall is configured to maintain the working fluid in the internal chamber in a liquid phase. The insulating layer of at least one wall is directly against the electrically conductive member of the electromagnetic power conversion device such that heat from the electrically conductive member evaporates the working fluid in the porous wicking lining of at least one wall and the working fluid condenses at or within the porous wicking lining of at least one other wall to cool the electrically conductive member of the electromagnetic power conversion device. The components may be in direct contact with the device as it operates and/or experiences time-varying magnetic fields that result in operation of the device.

In one embodiment, a heat pipe system includes a plurality of heat pipe assemblies configured to be disposed directly against an electrically conductive winding of an electric motor to cool the winding. Each of the heat pipe assemblies includes a plurality of connected walls having a porous wicking liner along the walls. The walls include at least an inner wall, an outer wall, and a connecting wall coupling the inner wall and the outer wall. Each of the heat pipe assemblies also includes an internal chamber disposed within and sealed by the wall. The porous wicking liner of the wall is configured to maintain the working fluid in the internal chamber in a liquid phase. The inner wall of the heat pipe assembly is configured to be positioned directly against the conductive windings of the motor such that heat from the conductive windings evaporates the working fluid in the porous wicking liner of the inner wall of the heat pipe assembly. The working fluid condenses at or within the porous wicking lining of the outer wall of the heat pipe assembly to cool the electrically conductive coil of the motor.

Technical solution 1. an electric motor for an aircraft, the electric motor comprising:

a stator;

a rotor disposed about the stator and configured to receive electrical current from a power source, the rotor operatively coupled with an aircraft propeller, the rotor configured to rotate about the stator to rotate the aircraft propeller and propel an aircraft; and

a heat pipe assembly coupled with one or more of the stator or the rotor, the heat pipe assembly comprising a plurality of connected inner chamber walls having a porous wicking lining along the walls, an insulating layer coupled with at least one inner chamber wall on a side of the at least one inner chamber wall opposite the porous wicking lining of the at least one inner chamber wall, and an inner chamber disposed within and sealed by the inner chamber wall,

wherein the porous wicking liner of the inner chamber wall is configured to maintain a working fluid in the inner chamber in a liquid phase,

wherein the insulating layer of the at least one inner chamber wall is directly against one or more of the stator or the rotor such that heat from one or more of the stator or the rotor vaporizes the working fluid in the porous wicking lining of the at least one inner chamber wall and the working fluid condenses at or within the porous wicking lining of at least one other inner chamber wall to cool one or more of the stator or the rotor.

Solution 2. the electric motor of solution 1 wherein one or more of the stator or the rotor includes one or more conductive windings such that heat from the one or more conductive windings vaporizes working fluid in the porous wicking lining of the at least one inner chamber wall and the working fluid condenses at or within the porous wicking lining of the at least one other inner chamber wall to cool the one or more conductive windings.

Solution 3. the electric motor of any preceding solution, wherein the inner chamber wall forms an elongated interior of the inner chamber that is located between and directly adjacent to adjacent ones of the one or more conductive windings.

Claim 4 the electric motor according to any preceding claim, wherein the interior of the internal chamber is elongate along the axis of rotation of the rotor.

Solution 5. the electric motor according to any preceding solution, wherein the inner chamber wall also forms an elongated exterior of the inner chamber, which is located outside the electrically conductive coil.

Claim 6 the electric motor according to any preceding claim, wherein the exterior of the inner chamber is elongate.

Claim 7 the electric motor of any preceding claim, further comprising elongated fins extending outwardly from the outer portion.

Technical solution 8 an aircraft motor, comprising:

a rotor configured to rotate about a stator and rotate an electrically driven propeller of an aircraft, the rotor comprising an electrically conductive coil through which an electrical current is conducted to rotate the rotor about the stator; and

a heat pipe assembly engaged with the electrically conductive coil of the rotor, the heat pipe assembly comprising a plurality of connected inner chamber walls having a porous wicking lining along the inner chamber walls forming and sealing an inner chamber, the porous wicking lining of the inner chamber walls configured to maintain a working fluid in the inner chamber in a liquid phase,

wherein at least one inner chamber wall is configured to be positioned such that heat from an electrically conductive coil of the rotor at least partially vaporizes a working fluid in a porous wicking liner of the at least one inner chamber wall, and the working fluid condenses at or within a porous wicking liner of at least one other inner chamber wall to cool the electrically conductive coil.

The aircraft motor of any preceding claim wherein the inner chamber wall forms an elongate fin that projects radially away from the axis of rotation of the rotor, and wherein the inner chamber extends into the fin.

The aircraft motor of any preceding claim, further comprising support posts between the interior chamber walls to structurally support the interior chamber walls away from each other.

Solution 11 the aircraft motor according to any preceding solution, wherein the inner chamber wall forms a rotor sleeve and an end plate, the rotor of the motor being located in the rotor sleeve and the end plate.

The aircraft motor of any preceding claim wherein the end plate comprises an elongated fin projecting axially away from the end plate in a direction parallel to the axis of rotation of the rotor, wherein the inner chamber extends into the elongated fin.

Technical solution 13 an electric aircraft motor comprising:

an electrically conductive winding configured to receive an electrical current to rotate the rotor about the stator; and

a plurality of heat pipe assemblies configured to be disposed directly against the conductive winding to cool the conductive winding, each of the heat pipe assemblies comprising:

a plurality of connected walls having a porous wicking liner along the walls, the walls comprising at least an inner wall, an outer wall, and a connecting wall coupling the inner wall with the outer wall; and

an interior chamber disposed within and sealed by the wall,

wherein the porous wicking liner of the wall is configured to maintain a working fluid in the internal chamber in a liquid phase,

wherein the inner wall of the heat pipe assembly is configured to be positioned directly against the electrically conductive winding such that heat from the electrically conductive winding evaporates working fluid in the porous wicking liner of the inner wall of the heat pipe assembly and the working fluid condenses at or within the porous wicking liner of the outer wall of the heat pipe assembly to cool the electrically conductive coil.

The aircraft motor of any preceding claim, wherein the walls of the heat pipe assembly form an elongated interior of the interior chamber between and directly adjacent ones of the one or more conductive windings, and the walls of the heat pipe assembly also form an elongated exterior of the interior chamber outside of the conductive windings.

The aircraft motor of any preceding claim, wherein the interior of the internal chamber is elongate in a direction parallel to the axis of rotation of the rotor.

The aircraft motor of any preceding claim, wherein the exterior of the interior chamber is elongated in a direction perpendicular to the axis of rotation of the rotor.

The aircraft motor of any preceding claim, further comprising an elongated fin extending outwardly from an exterior of the heat pipe assembly.

The aircraft motor according to any preceding claim wherein the electrically conductive winding extends around the axis of rotation of the rotor along a circular ring and wherein the exterior of a first set of heat pipe assemblies is located on a first side of the ring and the exterior of a second, non-overlapping set of heat pipe assemblies is located on a second, opposite side of the ring.

Solution 19. the aircraft motor according to any preceding solution, wherein the heat pipe assembly helps to automatically level the temperature differential of the conductive winding during operation of the electric motor.

Solution 20. the aircraft motor according to any preceding solution, wherein the heat pipe assemblies automatically level temperature differentials by receiving more current in a first set of electrically conductive windings that are cooler because the working fluid in the respective first set of heat pipe assemblies is directed closer to the electrically conductive windings in the first set of electrically conductive windings due to one or more of gravity or acceleration forces and less current in a different second set of electrically conductive windings that are hotter because the working fluid in the respective second set of heat pipe assemblies is directed farther away from the electrically conductive windings in the second set of electrically conductive windings due to one or more of gravity or acceleration forces.

Drawings

The subject matter of the invention will be better understood by reading the following description of non-limiting embodiments with reference to the attached drawings, in which:

fig. 1 shows one example of a cross-sectional view of a heat pipe assembly;

FIG. 2 illustrates a perspective view of one embodiment of a conformal heat pipe assembly with a conductive coil of a motor;

FIG. 3 is a perspective view of a portion of the electrically conductive coil and heat pipe assembly shown in FIG. 2;

FIG. 4 is a front view of a portion of the electrically conductive coil and heat pipe assembly shown in FIG. 2;

FIG. 5 illustrates a perspective view of another embodiment of a conformal heat pipe assembly and the electrically conductive coil of the motor shown in FIG. 2;

FIG. 6 is a perspective view of a portion of the electrically conductive coil and heat pipe assembly shown in FIG. 5;

FIG. 7 is a front view of a portion of the electrically conductive coil and heat pipe assembly shown in FIG. 5;

FIG. 8 illustrates a perspective view of another embodiment of a conformal heat pipe assembly and the electrically conductive coil of the motor shown in FIG. 2;

FIG. 9 is a perspective view of a portion of the electrically conductive coil and heat pipe assembly shown in FIG. 8;

FIG. 10 is a front view of a portion of the electrically conductive coil and heat pipe assembly shown in FIG. 8;

FIG. 11 is another perspective view of a portion of the electrically conductive coil and heat pipe assembly shown in FIG. 8;

FIG. 12 illustrates a cross-sectional view of one embodiment of a heat pipe assembly and the coil of the motor shown in FIG. 2;

FIG. 13 illustrates a cross-sectional view of another embodiment of a heat pipe assembly and the coil of the motor shown in FIG. 2;

FIG. 14 illustrates a cross-sectional view of another embodiment of a heat pipe assembly and the coil of the motor shown in FIG. 2;

FIG. 15 illustrates one embodiment of an end cap (end bell) conformal heat pipe assembly;

FIG. 16 illustrates a first cross-sectional view of an embodiment of a motor housing heat pipe assembly;

FIG. 17 is a second cross-sectional view of the motor housing heat pipe assembly shown in FIG. 16;

FIG. 18 illustrates a first cross-sectional view of an embodiment of a rotor sleeve heat pipe assembly;

FIG. 19 is a second cross-sectional view of the rotor sleeve heat pipe assembly shown in FIG. 18;

FIG. 20 illustrates a cross-sectional view of one embodiment of a rotor heat pipe assembly for an internal permanent magnet motor;

FIG. 21 illustrates a cross-sectional view of one embodiment of a rotor heat pipe assembly for an induction motor of the field wound motor;

FIG. 22 illustrates a cross-sectional view of one embodiment of a transformer winding or inductor winding heat pipe assembly;

FIG. 23 illustrates operation of one or more of the heat pipe assemblies shown in FIG. 8 in the motor disposed on the mobile system shown in FIG. 2;

FIG. 24 also illustrates operation of one or more of the heat pipe assemblies shown in FIG. 8 in the motor disposed on the mobile system shown in FIG. 2;

FIG. 25 also illustrates operation of one or more of the heat pipe assemblies shown in FIG. 8 in the motor disposed on the mobile system shown in FIG. 2;

FIG. 26 illustrates a flow diagram of one embodiment of a method for forming a heat pipe assembly for cooling a motor;

FIG. 27 illustrates an aircraft having a propulsion system; and

fig. 28 shows a power supply system.

Detailed Description

The subject matter described herein relates to heat pipes formed from one or more materials having a lower electrical conductivity than known heat pipes (e.g., significantly lower than copper). For example, the electrical conductivity of one or more materials used to form the heat pipes described herein may be at least an order of magnitude less than copper, and may be two or more orders of magnitude less than copper (in one embodiment). One or more embodiments of the heat pipe described herein may be formed from titanium, which has a significantly lower electrical conductivity than copper. High thermal conductivity ceramic insulation may be conformally coated onto the heat pipe by electrophoretic deposition (EPD) to achieve electrical isolation, which may both preserve the thermal performance of the heat pipe and improve the insulation performance of the heat pipe.

One embodiment of the inventive subject matter described herein provides a method that involves coating a surface of a heat pipe with a ceramic material comprising a nitride by an electrophoretic process to form a first coating. The method further includes contacting the first coating deposited by the electrophoretic process with a thermosetting resin to form a second coating; and curing the second coating to form an electrically insulating coating comprising a ceramic material dispersed in a polymer matrix. Suitable thermally conductive ceramic materials include aluminum nitride, boron nitride, diamond, alumina, or combinations thereof. Suitable thermosetting resins in the ceramic matrix include epoxy, silicone, polyester, polyurethane, cyanate ester, polyimide, polyamide, polyamideimide, polyesterimide, polyvinyl ester, or combinations thereof. Furthermore, by additive manufacturing, the conformal heat pipe may be form-fit to virtually any winding or coil shape of a machine. Finally, forming the heat pipe from high strength titanium allows for the replacement of structural elements in the heat pipe, such as the slot wedge, end caps, and/or motor housing, resulting in a dual thermo-mechanical structure with enhanced performance and reduced weight.

Thermal management in electrical machines typically involves the extraction of heat out of the magnetically active region by employing methods such as liquid or air cooled heat sinks. This approach may be referred to as "remote cooling". That is, heat generated in the machine is conducted from the heat source to the heat sink through multiple zones before the heat can be extracted. For example, in an electric motor, heat generated in the copper conductor may be conducted through inter-strand insulation, inter-turn insulation, potting resin, ground-wall insulation, winding-core interfaces, core laminations, core-shell interfaces, and fins before the heat can be expelled to the surrounding working fluid. The thermal conductivity of these different regions is limited (e.g. winding-0.5W/m-K, insulation-0.15W/m-K, encapsulation-resin-0.2W/m-K, lamination-25W/m-K). This approach therefore limits the amount of heat that can be extracted, and therefore the current that can be maintained in the device.

Improvements to the above approach may also be employed when higher performance and power density are desired, such as bringing the working fluid closer to the conductor where feasible (e.g., using a hollow conductor and flowing a heat absorbing working fluid directly adjacent to a heat generating conductor in the device). This method, known as "embedded cooling" or "direct conductor cooling", is currently used in high-pressure machines where the thickness of the insulating layer is significantly increased and the heat extracted by conventional methods is severely limited. This approach relies on a clean dielectric working fluid and requires additional infrastructure (e.g., flow distribution manifolds, hoses, and filters) to complete the flow, thereby increasing overall cost and design complexity and reducing overall power density.

In other applications, such as electronic cooling, heat pipes or internal chambers are increasingly being used to address similar heat extraction challenges. These devices operate on the principle of phase change heat transfer in a sealed tube or enclosure and, when properly designed, efficiently conduct heat from a remote, hard-to-reach heat source to a nearby convenient heat sink where heat can be more easily extracted with minimal or reduced temperature drop. Thus, a properly designed heat pipe may operate as a "hot superconductor" in a thermal management system. However, the adoption and acceptance of heat pipes in electromagnetic power conversion applications has been limited for a number of reasons, for example, commercially available heat pipes are typically made of copper. When such heat pipes are used in the vicinity of high frequency electromagnetic fields, significant eddy current induced heat generation is induced, resulting in an overall reduction in efficiency and performance. Furthermore, the area available for windings or coils in these devices is compact and the winding profile is non-standard (i.e., the windings are not always circular or rectangular).

Some known heat pipes or chambers may only be available in rectangular or cylindrical tube configurations, further limiting the use of these types of heat pipes or chambers in these applications. Furthermore, electrical insulation may need to be employed due to the voltage difference between the windings at the design potential and the heat pipes at ground potential. Typical electrical insulation materials (e.g., NOMEX, KAPTON, mica, and fiberglass) also have thermal insulation properties that, when used in the vicinity of the windings, reduce the overall efficiency of the heat pipe.

One or more embodiments of the inventive subject matter described herein address many, if not all, of the shortcomings of copper heat pipes described above. In addition, a form-fitting structural-thermo-mechanical element can be formed to further improve the thermal performance of the heat pipe while reducing the overall weight. The inventive heat pipe assembly described herein may be used as a heat pipe and internal chamber to cool electrically conductive coils of an electric motor (including motors with concentrated and/or distributed windings). The assembly may be a compliant inner chamber end cap assembly for use in a motor to cool end turns of motor windings of the motor. The assembly may be compliant in that the assembly has an external shape and/or dimensions that conform to (e.g., complement or match) the shape of at least a portion of the electric machine, such as the end windings.

The assembly may form a housing of the motor, wherein the housing has an inner chamber conforming to the shape of the motor. One embodiment of the assembly includes a sleeve or end plate of the rotor in the motor that includes a compliant inner chamber that cools the rotor. The assembly may provide rotor cooling for an Interior Permanent Magnet (IPM), a Surface Permanent Magnet (SPM), a single or dual excitation Induction Machine (IM), a Switched Reluctance Machine (SRM), a synchronous reluctance machine (SynRM) or a Field Winding Machine (FWM). The assembly may provide cooling for the windings of the transformer and/or inductor by means of a heat pipe or internal chamber built or formed in the bobbin of the transformer, with optional extension to the heat sink of the heat pipe to assist in the removal of heat from the windings.

Although many examples of the use of heat pipe assemblies are described herein, not all uses of heat pipe assemblies are limited to these examples. The heat pipe assembly may be used to cool other magnetic devices, machines or applications.

In one embodiment, the heat pipe assembly is formed of titanium or a titanium alloy. The heat pipe assembly may be formed by additive manufacturing the shape of the assembly so that it conforms to the shape of the device being cooled by the assembly. For example, the components may be created using three-dimensional (3D) printing, Rapid Prototyping (RP), Direct Digital Manufacturing (DDM), Selective Laser Melting (SLM), Electron Beam Melting (EBM), Direct Metal Laser Melting (DMLM), and the like.

The heat pipe assembly may be formed of another material instead of or in addition to titanium. For example, the heat pipe assembly may be formed of another thermally conductive but electrically resistive material, such as stainless steel.

The heat pipe assembly may be placed or formed in direct contact with the electrically conductive coil of the magnetic device described herein. This is in contrast to some known heat pipe assemblies, which may require the placement of an insulating material between the outer surface of the heat pipe assembly and the electrically conductive coil of the magnetic device. In contrast to some known heat pipe assemblies that are located outside of the time-varying electromagnetic fields, these heat pipe assemblies may be placed in these time-varying electromagnetic fields, which are generated for the device to operate. By applying the heat pipe assembly directly to the heat source in these devices, significant thermal performance advantages can be achieved over certain known heat pipe assemblies.

One or more embodiments of the inventive subject matter described herein relate to integrated thermal and mechanical assemblies that may be used in devices to cool conductive windings of the devices, including three-dimensionally printed, conformal interior chambers.

Fig. 1 shows one example of a cross-sectional view of a heat pipe assembly 100. An assembly 100 is shown in fig. 1 to describe the basic operation of how the conformal heat pipe assembly described herein removes thermal energy from an electrical and/or mechanical heat source (e.g., conductive windings of an electromagnetic device, such as a motor, an inductor, a transformer, an induction heating coil, etc.) under stable and/or unstable cooling conditions.

The assembly 100 includes a vapor enclosure 102 having a low thermal resistance. The housing 102 may be formed using additive manufacturing (e.g., three-dimensional printing), and/or the housing 102 may be formed from a material having low thermal resistance and low electrical conductivity (e.g., titanium, stainless steel, etc.). The vapor shell 102 defines and encloses an inner chamber 104. The chamber 104 may be hermetically sealed from the external environment such that working fluid (e.g., water) within the chamber 104 cannot exit the chamber 104 through the housing 102 and/or cannot enter the chamber 104 through the housing 102.

The housing 102 is defined by

several walls

106, 108, 110, 112 extending around the chamber 104 and surrounding the chamber 104. The

walls

106, 108, 110, 112 are provided merely as examples of how the various heat pipe assemblies described herein may operate to remove heat from the electromagnetic device. The number, size, and/or arrangement of the

walls

106, 108, 110, 112 may vary based on the shape of the electromagnetic device to which the heat pipe assembly is to conform. Additionally, if desired, additive manufacturing may be used to build support walls in specific locations within vapor space 104 to mechanically support outer shell 102 and provide additional rigidity to the structure. The support wall may be configured to allow continuous flow of vapor to provide minimal or reduced clogging.

Optionally, one or more exterior surfaces of

walls

106, 108, 110, and/or 112 may include insulation layer 116 or be coupled with insulation layer 116. The insulating layer 116 may be formed of a dielectric material, i.e., a material that is not thermally conductive (or less thermally conductive than the

walls

106, 108, 110, and/or 112) and/or is not electrically conductive (or less electrically conductive than the

walls

106, 108, 110, and/or 112). Examples of materials from which insulating layer 116 can be formed include polyamide, KAPTON, or NOMEX. In one embodiment, the insulating layer 116 is formed on one or more of the

walls

106, 108, 110, and/or 112 using electrophoretic deposition. Alternatively, another deposition technique is used.

In one embodiment, the interior surface of one or more of

walls

106, 108, 110, and/or 112 includes a porous wicking structure or liner 114, formed from or lined with porous wicking structure or liner 114. Porous wicking structure 114 may be formed using additive manufacturing, and may be formed from sintered powder. Alternatively, porous wicking structure 114 may be formed using another technique and/or from another material. Porous wicking structure 114 may line the entire interior surface of chamber 104 and may hold a liquid working fluid. Optionally, not all walls may include insulating layer 116 and/or porous wicking structure 114. For example, one or more walls may not include wicking structure 114, or a portion of at least one wall may not include wicking structure 114. As another example, one or more walls may not include insulating layer 116, or a portion of at least one wall may not include insulating layer 116. Optionally, one or more internal support rails or posts may extend from one wall to the opposite wall to mechanically support the walls away from each other.

Depending on which wall is adjacent to the device, the housing 102 conducts thermal energy from the electromagnetic device through the

walls

106, 108, 110, and/or 112. In some embodiments,

multiple walls

106, 108, 110, 112 may be in contact with the same or different devices at the same time. In one example of operation of the assembly 100, the wall 108 may be in direct contact with a heat source (e.g., a conductive winding of a device).

As the wall 108 absorbs thermal energy, the wall 108 transfers the thermal energy to a working fluid (e.g., water, ammonia, etc.) held within the chamber 104 and/or within the pores of the porous wicking structure 114 along the wall 108. The working fluid may be in a liquid state in the porous wicking structure 114. As the working fluid absorbs thermal energy, the fluid changes from a liquid phase to a gas phase and enters inner chamber 104. As the working fluid enters the chamber 104 and/or flows toward the

cooler walls

106, 110, and/or 112, the working fluid cools and condenses (e.g., changes phase from a vapor to a liquid). The liquid phase of the fluid then recirculates by gravity and/or capillary forces back to the chamber 104, where the fluid again absorbs thermal energy from the wall 108, thereby continuing the evaporation-condensation cycle.

For example, the sealed chamber 104 may maintain the liquid phase of the working fluid and the vapor phase of the working fluid in thermodynamic equilibrium. A very efficient heat transfer process occurs when heat is introduced into the chamber 104 (e.g., at one or more of the

walls

106, 108, 110, 112) and removed from the chamber 104 (e.g., at one or more of the

other walls

106, 108, 110, 112 that are further from the heat source). This process involves heat entering the

wall

106, 108, 110 or 112 and reaching the liquid working fluid in the porous wicking lining 114 of the

wall

106, 108, 110 or 112. The liquid working fluid is at least partially evaporated by the heat and the vapor moves to where the vapor can condense, such as the interior of the chamber 104 and/or another

wall

106, 108, 110, 112 that is further from the heat source. The vapor condenses back into the liquid phase and thereafter releases heat back to the

walls

106, 108, 110, 112 that are farther from the heat source. The liquid working fluid returns into porous wicking liner 114 and may be drawn back into inner chamber 104 by capillary action (e.g., capillary suction).

Fig. 2 illustrates a perspective view of one embodiment of the conformal heat pipe assembly 204 and the electrically conductive coil 200 of the motor 202. Fig. 3 is a perspective view of a portion of the conductive coil 200 and heat pipe assembly 204. Fig. 4 is a front view of a portion of the conductive coil 200 and heat pipe assembly 204. The motor 202 is one example of an electromagnetic power conversion device described herein. Only the annular portion 206 of the stator of the motor 202 is shown in fig. 2, and the motor 202 may include additional components. The annular portion 206 may represent a portion of the inner diameter or inner diameter of the stator. The loop 206 includes a plurality of conductive coils or windings 200 that, when current is passed, generate a magnetic field that interacts with the rotor (not shown) to cause the rotor to move.

The coil 200 may generate heat during operation of the motor 202. This heat may be dissipated or otherwise removed from the coil 200 by the heat pipe assembly 204. In the illustrated embodiment, heat pipe assembly 204 is an L-shaped body. Heat pipe assembly 204 includes an inner portion 210 and an outer portion 208, inner portion 210 extending between adjacent coils 200 of motor 202, and outer portion 208 disposed outside of coils 200 (e.g., not between coils 200). The inner portion 210 is elongated in an axial direction parallel to a central or rotational axis 216 of the motor 202. The outer portion 208 is elongated in a radial direction perpendicular to a central or rotational axis 216 of the motor 202. In the illustrated embodiment, the exterior 208 of the heat pipe assembly 204 is entirely located on one side of the annular portion 206 of the stator of the motor 202. Further, in the illustrated embodiment, the exterior of the heat pipe assembly 204 extends entirely radially outward (e.g., away from a central or rotational axis 216 of the motor 202).

As shown in fig. 1, heat pipe assembly 204 may include an interior chamber 104 having a porous wicking liner 114 with a working fluid therein. As described above in connection with the heat pipe assembly 100 shown in fig. 1, the heat pipe assembly 204 may help to quickly cool the coil 200 by removing heat from the coil 200. For example, the opposing

walls

106, 108 in the interior 210 of the heat pipe assembly 204 may be in direct contact with the adjacent coil 200. Heat from coil 200 evaporates the working fluid held in porous wicking liner 114 of

walls

106, 108, and the vapor working fluid can then move within inner chamber 104 of heat pipe assembly 204 into the less heated outer portion 208 of heat pipe assembly 204. The vapor working fluid may then condense back to a liquid working fluid (as described below), and then flow or be pulled (e.g., by capillary action) back into porous wicking liner 114 of interior 210.

The

walls

106, 108 of the interior 210 of each of the heat pipe assemblies 204 are in direct contact with the coil 200 on opposite sides of the heat pipe assembly 204, as shown in fig. 4. For example, no other material than the material forming the

walls

106, 108 may be disposed between the walls 106 and/or 108 and the nearest coil 200.

An exterior 208 of heat pipe assembly 204 includes a plurality of fins 212. These fins 212 may be hollow, elongated extensions that protrude outward from inner chamber 104 of exterior 208 of heat pipe assembly 204. This may allow the working fluid in inner chamber 104 of heat pipe assembly 204 to flow into fins 212. In operation, heat from coil 200 may evaporate the liquid phase of the working fluid in porous wicking liner 114 in plate 208 of interior 210 of heat pipe assembly 204, plate 208 being adjacent to or otherwise in contact with coil 200. The vaporized coolant may move in the portion of the internal chamber 104 located in the interior 210 of the heat pipe assembly 204 to the portion of the internal chamber 104 located in the exterior 208 of the heat pipe assembly 204.

The vaporized working fluid may condense in the portion of the inner chamber 104 located in the exterior 208 of the heat pipe assembly 204. At least some of the vaporized working fluid may flow into the hollow fins 212 of the exterior 208 of the heat pipe assembly 204 to reduce the time required for the vaporized working fluid to condense. This can rapidly cool the heat generated by the coil 200. The condensed working fluid may then flow back into the porous wicking liner 114 in the interior 210 of the heat pipe assembly 204. As shown, the heat pipe assembly 204 interfaces with fins 212 that conform to an air-cooled arrangement. Alternatively, heat pipe assembly 204 may instead interface with a liquid heat exchanger that conforms to a liquid-cooled arrangement. In an alternative embodiment, the fins 212 may be separate entities, and the fins 212 are attached to the heat pipe using epoxy, solder, or similar bonding operations, thereby ensuring thermal communication between the heat pipe body and the fins.

Fig. 5 illustrates a perspective view of another embodiment of the conformal heat pipe assembly 504 and the conductive coil 200 of the motor 202. Fig. 6 is a perspective view of a portion of the conductive coil 200 and heat pipe assembly 504. Fig. 7 is a front view of a portion of the conductive coil 200 and heat pipe assembly 504.

In the illustrated embodiment, the heat pipe assembly 504 is an L-shaped body. The heat pipe assembly 504 includes an inner portion 510 and an outer portion 508, the inner portion 510 extending between adjacent coils 200 of the motor 202, the outer portion 508 being disposed outside of the coils 200 (e.g., not between the coils 200). The inner portion 510 is elongated in an axial direction parallel to the central or rotational axis 216 of the motor 502. The outer portion 508 is elongated in a radial direction perpendicular to the central or rotational axis 216 of the motor 202. In the illustrated embodiment, the exterior 508 of the heat pipe assembly 504 is entirely located on one side of the annular portion 206 of the stator of the motor 202. Additionally, in the illustrated embodiment, the exterior of the heat pipe assembly 504 extends entirely radially inward (e.g., toward the central or rotational axis 216 of the motor 202), as opposed to the heat pipe assembly 204 illustrated in fig. 2-4.

As shown in fig. 1, heat pipe assembly 504 may include an interior chamber 104 having a porous wicking liner 114 with a working fluid therein. As described above, the heat pipe assembly 504 may help to quickly cool the coil 200 by removing heat from the coil 200. For example, the opposing

walls

106, 108 in the interior 510 of the heat pipe assembly 504 may be in direct contact with the adjacent coil 200. Heat from the coil 200 evaporates the working fluid held in the porous wicking liner 114 of the

walls

106, 108, and then the vapor working fluid can move within the interior chamber 104 of the heat pipe assembly 504 into the less heated exterior 508 of the heat pipe assembly 504. As described above, at least some of the vapor working fluid may enter the fins 212 of the exterior 508 of the heat pipe assembly 504. The vapor working fluid may then condense back to a liquid working fluid and then flow or be pulled (e.g., by capillary action) back into the porous wicking liner 114 of the interior 510.

The

walls

106, 108 of the interior 510 of each of the heat pipe assemblies 504 are in direct contact with the coil 200 on opposite sides of the heat pipe assembly 504, as shown in fig. 8. For example, no other material than the material forming the

walls

Fig. 8 illustrates a perspective view of another embodiment of the conformal heat pipe assembly 804 and the conductive coil 200 of the motor 202. Fig. 9 is a perspective view of a portion of the conductive coil 200 and heat pipe assembly 804. Fig. 10 is a front view of a portion of the conductive coil 200 and heat pipe assembly 804. Fig. 11 is another perspective view of a portion of the conductive coil 200 and heat pipe assembly 804.

In the illustrated embodiment, the heat pipe assembly 804 is an L-shaped body. The heat pipe assembly 804 includes an inner portion 810 and an outer portion 808, the inner portion 510 extending between adjacent coils 200 of the motor 202, and the outer portion 508 disposed outside of the coils 200 (e.g., not between the coils 200). The inner portion 810 is elongated in an axial direction parallel to the central or rotational axis 216 of the motor 502. The outer portion 808 is elongated in a radial direction perpendicular to the central or rotational axis 216 of the motor 202. In the illustrated embodiment, the exterior 808 of the heat pipe assembly 804 is located on the opposite side of the annular portion 206 of the stator of the motor 202. For example, the outer portions 808 may alternate between sides of the annular portion 206 such that the heat pipe assemblies 804 adjacent to each other have the outer portions 808 on opposite sides of the annular portion 206. Heat pipe assemblies 804 adjacent to each other may have an interior 810 in contact with opposite sides of the same coil 200. Further, the exterior of the heat pipe assembly 804 all extends radially outward (e.g., away from the central or rotational axis 216 of the motor 202).

As shown in fig. 1, heat pipe assembly 804 may include an interior chamber 104 having a porous wicking liner 114 with a working fluid therein. As described above, the heat pipe assembly 804 may help to rapidly cool the coil 200 by removing heat from the coil 200. For example, the opposing

walls

106, 108 in the interior 810 of the heat pipe assembly 804 may be in direct contact with the adjacent coil 200. Heat from the coil 200 evaporates the working fluid held in the porous wicking liner 114 of the

walls

106, 108, and then the vapor working fluid can move within the interior chamber 104 of the heat pipe assembly 804 into the less heated exterior 808 of the heat pipe assembly 804. As described above, at least some vapor working fluid can enter fins 212 of exterior 808 of heat pipe assembly 804. The vapor working fluid may then condense back to a liquid working fluid and then flow or be pulled (e.g., by capillary action) back into the porous wicking liner 114 of the interior 810.

As shown in fig. 9, 10 and 11, the

walls

106, 108 of the interior 810 of each of the heat pipe assemblies 804 are in direct contact with the coil 200 on opposite sides of the heat pipe assembly 804. For example, no other material than the material forming the

walls

Fig. 12 shows a cross-sectional view of one embodiment of a heat pipe assembly 1204 with the coil 200 of the motor 202. The cross-sectional view may represent a two-dimensional plane oriented perpendicular to the rotational axis 216 of the motor 202. In the illustrated embodiment, the motor 202 has coils 200 arranged in concentrated windings. The heat pipe assembly 1204 may represent one or more of the

heat sink assemblies

204, 504, 804 described above. The cross-sectional view of fig. 12 only shows a cross-section of the interior of the heat pipe assembly 1204. As shown, heat pipe assembly 1204 has a hollow interior chamber 104 with

walls

106, 108 adjacent to and/or in contact with coil 200. In the illustrated embodiment, the interior of the heat pipe assembly 1204 has a rectangular cross-sectional shape. The annular portion 206 of the stator of the motor 202 may optionally include a mandrel 1200, and the mandrel 1200 may be magnetic or non-magnetic in various embodiments.

Fig. 13 illustrates a cross-sectional view of another embodiment of the heat pipe assembly 1304 with the coil 200 of the motor 202. The cross-sectional view may represent a two-dimensional plane oriented perpendicular to the rotational axis 216 of the motor 202. In the illustrated embodiment, the motor 202 has coils 200 arranged in concentrated windings. The heat pipe assembly 1304 may represent one or more of the

heat sink assemblies

204, 504, 804 described above. The cross-sectional view of fig. 13 only shows a cross-section of the interior of the heat pipe assembly 1304. As shown, the heat pipe assembly 1304 has a hollow interior chamber 104, with the walls of the assembly 1304 adjacent to and/or in contact with the coil 200. In the illustrated embodiment, the interior of the heat pipe assembly 1304 has a T-shaped cross-sectional shape. This shape causes a radial portion 1300 of the inner chamber 104 to elongate in a direction perpendicular to the axis of rotation 216, and a circumferential portion 1302 of the inner chamber 104 to elongate in a direction that encircles the axis of rotation 216 or otherwise does not intersect the axis of rotation 216. For example, the inner chamber 104 may be elongated in a direction orthogonal to the axis of rotation 216. Such a shape of the heat pipe assembly 1304 may provide more contact between the coil 200 and the heat pipe assembly 1304 relative to the embodiment shown in fig. 12. This may result in heat being transferred more quickly from the coil 200 to the heat pipe assembly 1304 to more quickly cool the coil 200. Alternatively, the heat pipe assembly 1304 may operate as an integrated ram of a motor.

Fig. 14 shows a cross-sectional view of another embodiment of the heat pipe assembly 1404 with the coil 200 of the motor 202. The cross-sectional view may represent a two-dimensional plane oriented perpendicular to the rotational axis 216 of the motor 202. In the illustrated embodiment, the motor 202 has coils 200 arranged to distribute windings. The annular portion 206 of the stator of the motor 202 may optionally include the push rod 1200 described above.

The heat pipe assembly 1404 may represent one or more of the

heat sink assemblies

204, 504, 804 described above. The cross-sectional view of fig. 14 only shows a cross-section of the interior of the heat pipe assembly 1404. As shown, heat pipe assembly 1404 has a hollow interior chamber 104, with

walls

106, 108 of assembly 1404 adjacent to and/or in contact with coil 200. In the illustrated embodiment, the interior of the heat pipe assembly 1404 has a rectangular cross-sectional shape. While the interior of the heat pipe assembly 1204 shown in fig. 12 is elongated in a direction extending radially toward or away from the rotational axis 216 of the motor 202, the interior of the heat pipe assembly 1404 is elongated in a circumferential direction along the circumferential axis 216.

Fig. 15 illustrates one embodiment of an end cap conformal heat pipe assembly 1500. The heat pipe assembly 1500 is formed in an end cap 1502 coupled to the motor 202 or formed as an end cap 1502 coupled to the motor 202. The end cap 1502 is coupled with the stator housing 1504 of the stator 1506 of the motor 202. The end cap 1502 includes a recess 1508 whose shape conforms to the shape of the coil 200 of the motor 202. For example, the recess 1508 may have a U-shape or other concave shape that individually receives the individual coils 200 of the motor 202.

The end cap 1502 may be formed (e.g., using additive manufacturing) to include a heat sink assembly 1510 in the end cap 1502. The assembly 1510 may be shaped to match the curved shape of the coil 200, as shown in fig. 15. For example, the convex shape of coil 200 may extend into the concave shape of assembly 1510. These components 1510 include an interior chamber 104 defined and surrounded by the inner porous wicking liner described above. For example, one curved wall 1512 of assembly 1510 can be an evaporator wall of assembly 1510 that includes a porous wicking liner, while the opposite curved or flat wall 1514 of assembly 1510 can be a condenser wall that includes another porous wicking liner. The end cap 1502 may optionally include a gap pad 1516, which gap pad 1516 may be a flexible, thermally conductive material that engages the coil 200. The gap pads 1516 can engage the coil 200 without causing mechanical damage to the end turns of the coil 200 (e.g., the visible portion of the coil 200 in fig. 15), while also conducting heat from the coil 200 to the assembly 1510.

In operation, heat from the end turns of coil 200 is received by evaporator wall 1512 of assembly 1510. This heat vaporizes the liquid working fluid in the porous wicking liner of the evaporator wall 1512. The working fluid moves toward the condenser wall 1514 where it condenses to form a liquid working fluid. By this evaporation and condensation, heat from the end turns of the coil 200 is discharged from the coil 200. The heat pipe assembly 1500 formed in the end cap 1502 of the motor 202 can be used alone or in combination with one or more of the other heat pipe assemblies described herein to rapidly cool the electrically conductive coil of the motor.

Fig. 16 illustrates a first cross-sectional view of one embodiment of a motor housing heat pipe assembly 1600. Fig. 17 shows a second cross-sectional view of the motor housing heat pipe assembly 1600. The view shown in fig. 16 is along a two-dimensional plane parallel to or including the axis of rotation 216 of the motor 202. The view shown in fig. 17 is along another two-dimensional plane perpendicular to the axis of rotation 216. As shown, the motor 202 may include an end cap 1502. Optionally, the end cap 1502 may be formed as the end cap conformal heat pipe assembly 1500 described above.

The heat pipe assembly 1600 is formed in or as an exterior housing 1602 of the motor 202. The heat pipe assembly 1600 may be formed using additive manufacturing. The heat pipe assembly 1600 may be used to cool the motor 202, and may be used in combination with one or more of the other heat pipe assemblies described herein. The housing 1602 includes an inner wall 1604 and an opposing wall 1606 with a sealed interior chamber 1608 between the

walls

1604, 1606. The

walls

1604, 1606 may comprise a porous wicking liner as described herein. The working fluid may be disposed in the pores of the chamber 1608 and/or the

walls

1604, 1606.

The inner wall 1604 may be directly adjacent to the stator housing 1504 to cool the stator housing 1504. The opposing wall 1606 optionally includes elongated fins 1610 that project outwardly from the stator housing 1504. The fins 1610 may be hollow extensions of the internal chamber 1608 such that working fluid may flow within the fins 1610. In operation, heat from the stator housing 1504 causes the liquid working fluid to evaporate in the pores of the porous lining of the wall 1604. The vaporized working fluid flows radially inward from the wall 1604 into the inner chamber 1608, and optionally to portions of the inner chamber 1608 that are within the fins 1610. The fins 1610 allow the vaporized working fluid to move farther away from the heat source (e.g., motor), and a plurality of fins 1610 are provided so that smaller portions of the vaporized working fluid are separately cooled. These features can rapidly condense the vaporized working fluid by transferring heat from the motor 202 out of the assembly 1600, and thereby rapidly cool the motor 202.

As shown in fig. 17, heat pipe assembly 1600 may optionally include one or more support posts 1700. Post 1700 is a structural member that helps

separate walls

1604, 1606 from one another by mechanically supporting wall 1606 outside of wall 1604. The posts 1700 may be formed from the same material and/or using additive manufacturing. Alternatively, the post 1700 may divide the inner chamber 1608 into several smaller chambers 1608. The column 1700 may include a porous wicking liner 114 to help move the condensed working fluid from the side where the fluid condenses back to the side where the fluid evaporates after being heated.

Fig. 18 shows a first cross-sectional view of an embodiment of a rotor sleeve heat pipe assembly 1800. Fig. 19 shows a second cross-sectional view of rotor sleeve heat pipe assembly 1800. The view shown in fig. 18 is along a two-dimensional plane parallel to or including the axis of rotation 216 of the motor 202. The view shown in fig. 19 is along another two-dimensional plane perpendicular to the axis of rotation 216. The rotor 1802 of the motor 202 (shown in fig. 16) is disposed within the stator 1506 (shown in fig. 15). The rotor 1802 is coupled to the elongate shaft 1804, and both the rotor 1802 and the shaft 1804 rotate about the axis of rotation 216.

The heat pipe assembly 1800 may be formed as a sleeve and/or end plate on the rotor 1802. Heat pipe assembly 1800 can be disposed between rotor 1802 and stator 1506 to cool rotor 1802 and optionally stator 1506. The heat pipe assembly 1800 includes a sleeve portion 1808 and an end plate portion 1806. The sleeve portion 1808 is elongated in a direction parallel to the axis 216, while the end plate portion 1806 is elongated in a direction perpendicular to the axis 216. The end plate portion 1806 may be formed as a circular plate having an opening through which the shaft 1804 extends. In fig. 18, only half of the sleeve and

end plate portions

1808, 1806 are shown.

The heat pipe assembly 1800 may be formed using additive manufacturing. The heat pipe assembly 1800 can be used to cool the rotor 1802 and can be used in conjunction with one or more other heat pipe assemblies described herein. The

portions

1806, 1808 of the heat pipe assembly 1800 include an inner wall 1810 and an opposing wall 1812 with a sealed interior chamber 1814 between the

walls

1810, 1812. The

walls

1810, 1812 may include a porous wicking liner as described herein. The working fluid may be disposed in the chamber 1814 and/or the pores of the

walls

1810, 1812.

The inner wall 1810 may directly abut an outer surface of the rotor 1802, as shown in fig. 18. The end plate portion 1806 optionally includes an elongated fin 1610 that projects outwardly from an outer wall 1812 of the end plate portion 1806. As described above, the fins 1610 may be hollow extensions of the internal chamber 1814 such that the working fluid may flow within the fins 1610. In operation, heat from the rotor 1802 vaporizes the liquid working fluid in the pores of the porous lining of the wall 1810. The vaporized working fluid flows radially (in the sleeve portion 1808) and axially (in the end plate portion 1806) from the wall 1810 to portions of the internal chambers 1814 and optionally to portions of the internal chambers 1814 within the fins 1610. The vaporized working fluid may then condense and return to the pores in the wall 1810. In one embodiment, centrifugal force may help return the working fluid to one side of the heat pipe assembly where evaporation of the working fluid occurs.

As shown in fig. 19, the heat pipe assembly 1800 optionally may include one or more support posts 1700. As described above, post 1700 is a structural member that helps

separate walls

1810, 1812 from one another by mechanically supporting walls 1812 outside of walls 1810. The posts 1700 may be formed from the same material and/or using additive manufacturing. Alternatively, the column 1700 may divide the interior chamber 1814 into several smaller chambers 1814.

Fig. 20 illustrates a cross-sectional view of one embodiment of a rotor heat pipe assembly 2000 for an internal permanent magnet motor. The view shown in fig. 20 is along a two-dimensional plane perpendicular to the axis of rotation of the rotor of the interior permanent magnet motor. Only a portion of the rotor 2001 and shaft 2003 of the inner permanent magnet motor is shown in fig. 20.

The heat pipe assembly 2000 is formed as a rectangular box in which the permanent magnet 2006 of the inner permanent magnet motor is placed. A plurality of heat pipe assemblies 2000 may be provided, for example one assembly 2000 for each permanent magnet in an internal permanent magnet motor. The heat pipe assembly 2000 may be formed using additive manufacturing. The heat pipe assembly 2000 may be used to cool the magnet 2006. The heat pipe assembly 2000 includes an inner wall 2002 and an opposing wall 2004 with a sealed inner chamber 2006 between the

walls

2002, 2004. The

walls

2002, 2004 may include a porous wicking liner as described herein. The working fluid may be disposed in the chamber 2006 and/or the pores of the

walls

2002, 2004.

The inner wall 2002 may directly abut the outer surface of the magnet 2006. In operation, heat from the magnet 2006 vaporizes the liquid working fluid in the pores of the porous lining of the inner wall 2002. The vaporized working fluid flows radially from the inner wall 2002 to the inner chamber 2008 and the outer wall 2004. This can help to carry heat away from the magnet 2006 and cool it. The vaporized working fluid may condense and return to the inner wall 2002 as described herein.

Fig. 21 schematically illustrates a cross-sectional view of one embodiment of a rotor heat pipe assembly 2100 for an induction motor of a field wound motor. The view shown in fig. 21 is along a two-dimensional plane perpendicular to the rotational axis 2126 of the rotor 2102 of the induction motor. Only a portion of the rotor 2102 is shown in fig. 21.

The rotor 2102 includes a plurality of conductive rods or bars 2104 that are elongated in a direction parallel to the rotational axis 2126 of the rotor 2102. This axis 2126 is oriented perpendicular to the view of fig. 21 (e.g., into and out of the page of fig. 21). These strips 2104 are placed in openings in the rotor 2102. Several heat pipe assemblies 2100 may be formed around the strip 2104. The heat pipe assembly 2100 may be in direct contact with the strip 2104. For example, as shown in fig. 21, each heat pipe assembly 2100 is formed as a cylindrical sleeve with one of the strips 2104 positioned therein, the heat pipe assembly 2100 and the strips 2104 being placed in an opening in the rotor 2102.

Additive manufacturing may be used to form the heat pipe assembly 2100. The heat pipe assembly 2100 may be used to cool the strip 2104; the strips 2104 may become hot during operation due to the varying magnetic field in which the strips 2104 are exposed to rotate the rotor 2102. Although only five strips 2104 are shown including the heat pipe assembly 2100, the heat pipe assembly 2100 may alternatively be provided for a different number of strips 2104 or all strips 2104.

Each of the heat pipe assemblies 2100 may include an inner wall 2106 and an opposing outer wall 2108 with a sealed inner chamber 2110 between the

walls

2106, 2108. The

walls

2106, 2108 may include a porous wicking liner as described herein. The working fluid may be disposed within the chamber 2110 and/or the apertures of the

walls

2106, 2108. Inner wall 2106 may be directly adjacent the outer surface of strip 2104. In operation, heat from the strips 2104 causes the liquid working fluid to evaporate in the pores of the porous lining of the inner wall 2106. The vaporized working fluid flows radially from the inner wall 2106 to the inner chamber 2110 and the outer wall 2108. This can help to carry heat away from the strips 2104 and cool them. The working fluid may condense and return to the inner wall 2106 as described herein.

Fig. 22 illustrates a cross-sectional view of one embodiment of a transformer winding or inductor winding heat pipe assembly 2200. The heat pipe assembly 2200 may be used to cool the conductive winding 2202 of the transformer or inductor device 2204. The winding 2202 may be helically wound on the bobbin 2206, and the heat pipe assembly 2200 may be located at least partially between the winding 2202 and the bobbin 2206. Magnetic core 2208 of device 2204 is positioned such that winding 2202 extends around opposing sections of magnetic core 2208 separated by an insulating gap. Alternatively, the heat pipe assembly 2200 may form the bobbin 2206. For example, the heat pipe assembly 2200 may be formed as a cylinder wrapped with windings 2202.

As shown, the heat pipe assembly 2200 may be formed to include a ridge 2201, the ridge 2201 extending radially away from a central axis of the heat pipe assembly 2200 or the bobbin 2206. The ridges may be sized and positioned to accommodate different windings 2202. The ridges increase the surface area of the windings 2202 that engages the heat pipe assembly 2200, which can increase the rate at which heat is transferred from the windings 2202 to the heat pipe assembly 2200. The ridges may optionally provide guidance for where the windings 2202 will be located during transformer manufacturing.

In operation, winding 2202 may become hot due to the changing magnetic field generated around magnetic core 2208 by the current flowing through winding 2202. The heat pipe assembly 2200 may help cool the windings 2202. The heat pipe assembly 2200 may be wound around the bobbin 2206 between the winding 2202 and the bobbin 2206. The heat pipe assembly 2200 includes opposing inner and

outer walls

2210, 2212, with a sealed interior chamber 2214 between the

walls

2210, 2212. The

walls

2210, 2212 may include a porous wicking lining 114 as described herein, with a working fluid in the pores of the lining 114 and the chamber 2214. Wall 2212 may be in direct contact with windings 2202. For example, there may not be any other material between wall 2212 and winding 2202.

The heat pipe assembly 2200 may also include a chamber extension 2216 that is an extension of the interior chamber 2214 that is not disposed between the winding 2202 and the bobbin 2206. In the illustrated embodiment, the extension 2216 is formed by the

walls

2210, 2212 and the portion of the chamber 2214 that extends beyond the windings 2202 along the length of the bobbin 2206, as shown in fig. 22. The

walls

2210, 2212 may surround the coil bobbin 2206 such that the heat pipe assembly 2200 forms a cylindrical sleeve with the coil bobbin 2206 disposed therein. Chamber extension 2216 may be the portion of this cylindrical sleeve that extends beyond windings 2202.

Additive manufacturing may be used to form the heat pipe assembly 2200. The heat pipe assembly 2200 may be used to cool the winding 2202, which winding 2202 may become hot during operation of the device 2204. In operation, heat from windings 2202 vaporizes liquid working fluid in the pores of the porous lining of wall 2212 and potentially in the pores of wall 2210. The vaporized working fluid flows axially in the chamber 2214 along the length of the bobbin 2206 toward the chamber extension 2216. For example, the vaporized working fluid increases the air pressure within chamber 2214 in the location between windings 2202 and bobbin 2206. This increased pressure may cause the vaporized working fluid to flow along the length of the bobbin 2206 in the chamber 2214 to the chamber extension 2216.

The temperature within chamber extension 2216 may be reduced relative to the temperature within chamber 2214 between winding 2202 and bobbin 2206. This may be due to the heated windings 2202 being farther from the chamber extension 2216. The colder temperature in chamber extension 2216 may cause the vaporized working fluid to condense, thereby transferring thermal energy out of heat pipe assembly 2200 and helping to cool winding 2202. The liquid working fluid may then flow back into the pores of the

walls

2210, 2212 and into the chamber 2214 at a location between the winding 2202 and the bobbin 2206 to continue to cool the winding 2202.

Fig. 23-25 illustrate operation of one or more heat pipe assemblies 804 disposed in the motor 202 on the mobile system. Although the description and illustration focus on the heat pipe assembly 804, the description may also apply to other heat pipe assemblies described herein. The motor 202 may be subject to different gravitational and other forces due to acceleration of the vehicle on a moving system such as a vehicle (e.g., an aircraft such as a fixed wing aircraft or a helicopter). For example, during takeoff of an aircraft from the ground (as shown in FIG. 23), pull to the ground due to gravity (e.g., due to gravity)g) And acceleration of the aircraft away from the ground (e.g. acceleration of the aircraft away from the ground)a) The motor 202 may experience acceleration forcesa+g. These forces may cause the working fluid in the heat pipe assembly 804 to be drawn to one wall or side of the internal chamber within the assembly 804 rather than another wall or side.

For example, the heat pipe assembly 804 (relative to the direction of vehicle acceleration, or below the motor 202 in fig. 23) below the motor 202 may pull the working fluid away from a location between the electrically conductive coils 200 of the motor 202. This may result in reduced cooling of the coil 200 by the heat pipe assembly 804 located below the motor 202 (relative to a heat pipe assembly 804 operating without acceleration forces a and/or gravity g acting on the working fluid). However, the heat pipe assembly 804 above the motor 202 (relative to the direction of vehicle acceleration, or above the motor 202 in fig. 23) may cause the working fluid to be pulled into position between the electrically conductive coils 200 of the motor 202. This results in increased cooling of the coil 200 by the heat pipe assembly 804 located above the motor 202 (relative to a heat pipe assembly 804 operating without acceleration forces a and/or gravity g acting on the working fluid).

The net effect of reduced cooling of one half of heat pipe assembly 804 and increased cooling of the other half of heat pipe assembly 804 may result in cooling of coil 200 without acceleration forces on coil 200aAnd/or gravitygThe cooling obtained under the influence of the action of the working fluid has the same rate and/or the same amount. For example, the increased cooling of the heat pipe assembly 804 above the motor 202 may offset and compensate for the reduced cooling of the heat pipe assembly 804 below the motor 202.

As another example, during constant-speed cruising of an aircraft (as shown in fig. 24), the direction of movement of the aircraft may be parallel to the ground, rather than away from the ground (e.g., takeoff) or toward the ground (e.g., landing). The motor 202 may experience gravity due to the pulling force of gravity toward the groundg. These forces may cause the working fluid in the heat pipe assembly 804 on the lower half of the motor 202 (e.g., below the bisecting plane 2400) to be drawn to one wall or side of the internal chamber within the assembly 804 rather than the other wall or side. For example, the heat pipe assembly 804 below the plane 2400 may pull the working fluid away from a location between the conductive coils 200 of the motor 202. This results in reduced cooling of the coil 200 by the heat pipe assembly 804 located below the motor 202 (relative to the absence of gravity)gA heat pipe assembly 804 operating under the action of a working fluid). However, the heat pipe assembly 804 above the plane 2400 may cause the working fluid to be pulled into position between the conductive coils 200 of the motor 202. This results in increased cooling of coil 200 by heat pipe assembly 804 located below plane 2400 (relative to when there is no gravity force)gA heat pipe assembly 804 operating under the action of a working fluid).

The coils of the motor may be wound with parallel paths such that the upper half of the motor forms one parallel path, andthe lower half of the motor forms a second parallel path. By adding parallel winding paths to the motor, the net effect of reduced cooling of one half of heat pipe assembly 804 and increased cooling of the other half of heat pipe assembly 804 may result in cooling of coil 200 from the force of gravity on coil 200gThe cooling obtained under the influence of the action of the working fluid has the same rate and/or the same amount. For example, the increased cooling of heat pipe assembly 804 above plane 2400 may offset and compensate for the reduced cooling of heat pipe assembly 804 below plane 2400. This temperature leveling occurs because the positive temperature coefficient of resistivity of copper is a function of temperature.

If the temperature of the coils in the upper half of the motor is lower than the temperature of the coils in the lower half of the motor, the current conducted in the coils is redistributed because the amount of current conducted in the coils in the upper half of the motor increases while the amount of current conducted in the coils in the lower half of the motor decreases. This occurs because the current is more easily conducted in the lower half of the motor where the temperature is lower than in the lower half of the motor where the temperature is higher. This will result in an increase in the temperature of the cooler coils on the upper half of the motor (due to the greater current conducted in these coils) and a decrease in the temperature of the warmer coils on the lower half of the motor (due to the smaller current conducted in these coils). In effect, the combination of parallel winding paths and heat pipe cooling forms a "self-leveling" process that compensates for increased or decreased cooling (where applicable) due to the orientation of the heat pipe assembly.

Although only two parallel winding paths of the coil (e.g., an upper half coil and a lower half coil) are shown and described, the motor windings may be split into different numbers of parallel winding paths up to and including each motor winding being parallel to all other windings. For example, the winding in the upper half of the motor may be one parallel conductive path, while the winding in the lower half of the motor may be another different parallel conductive path. Alternatively, more than two parallel paths may be provided.

As another example, during cruise of the aircraft, the aircraft may be parallel to the groundAccelerating in the direction (as shown in fig. 25). During this lateral or horizontal acceleration, the motor 202 may experience acceleration forces in different directionsaAnd gravityg. Acceleration forceaThe working fluid may be pulled in one direction (e.g., opposite the "cruise acceleration" arrow in FIG. 25), while gravity pullsgThe working fluid may be pulled in a vertical direction (e.g., toward the ground). These forces may cause the working fluid in the heat pipe assembly 804 to be drawn in different directions.

For example, the heat pipe assembly 804 along the leading side of the motor 202 (e.g., the right side of the motor 202 in fig. 25) and above the bisecting plane 2400 may let acceleration forcesaAnd gravitygBoth of which pull the working fluid in these assemblies 804 to a position between the coils 200. This may result in significantly improved cooling of the coil 200 relative to the other heat pipe assemblies 804. Conversely, the heat pipe assembly 804 along the opposite trailing end side of the motor 202 (e.g., the left side of the motor 202 in fig. 25) and below the bisecting plane 2400 may let acceleration forcesaAnd gravitygBoth of which pull the working fluid in these assemblies 804 away from the coil 200. This may result in a substantial reduction in cooling of the coil 200 relative to the other heat pipe assemblies 804.

The heat pipe assembly 804 along the leading side of the motor 202 and below the bisecting plane 2400 may let acceleration forcesaThe working fluid in these assemblies 804 is pulled to a position between the coils 200, but gravitygPulling the working fluid away from the location between the coils 200. This may result in improved cooling of the coil 200 relative to other heat pipe assemblies 804 above the plane 2400 and along the lead side of the motor 202 than the heat pipe assembly 804. The heat pipe assembly 804 along the trailing end side of the motor 202 and above the bisecting plane 2400 may let gravity passgThe working fluid in these assemblies 804 is pulled to a position between the coils 200, but acceleration forces may also be permittedaThe working fluid in these assemblies 804 is pulled to a location not between the coils 200. This may result in improved cooling of the coil 200 relative to the heat pipe assembly 804 outside of the heat pipe assembly 804 above the plane 2400 and along the lead-in side of the motor 202.

The difference in the different number of cooling heat pipe assemblies 804The net effect of the quadrants may result in cooling of the coil 200 and the coil 200 being free of acceleration forcesaAnd/or gravitygThe cooling obtained under the influence of the action of the working fluid has the same rate and/or the same amount.

Fig. 26 illustrates a flow diagram of one embodiment of a method 2600 for forming a heat pipe assembly for cooling an electric machine. The method 2600 may be used to create one or more of the heat pipe assemblies shown and/or described herein. Two or more of the operations described in connection with method 2600 may be performed concurrently (e.g., concurrently or synchronously) or may be performed sequentially.

At 2602, the interior of the heat pipe assembly is formed. The interior of the heat pipe assembly may define a portion of a vapor chamber shaped to abut or be proximate to the electrically conductive portion of the motor. For example, the interior may be sized to fit between coils of the stator, may be configured to fit against coils of the stator, may be configured to be placed outside of a stator of the motor, may be configured to be placed between a rotor and a stator of the motor, may be configured to be placed around or between a magnet inserted into the rotor and a surrounding portion of the rotor in the motor, may be configured to be placed around or between a conductive rod inserted into the rotor and a surrounding portion of the rotor in the motor, may be configured to be placed around or against a conductive coil of a transformer, and so forth. The interior may be formed with a porous wicking structure on one or more interior surfaces of the interior. As described above, the wicking structure may retain a working fluid to help cool the motor. Additive manufacturing may be used in one embodiment to create the interior of the heat pipe assembly.

Alternatively, the inner portion may be formed with one or more inner support posts. As mentioned above, these posts may mechanically support opposite sides of the heat pipe assembly from moving relative to each other during operation of the motor.

At 2604, an exterior of the heat pipe assembly is formed. The outer portion may be formed together with the inner portion, for example by additive manufacturing the inner and outer portions simultaneously or in the same printing process. Alternatively, the inner and outer portions may be formed at different times. The outer portion may also include an inner porous wicking structure to retain or assist in condensing the working fluid.

The exterior may be formed remote from a heat source that vaporizes the working fluid in the interior of the heat pipe assembly. For example, the inner and outer portions may be formed in an L-shape, with the inner portion shaped to fit between adjacent coils of a stator of the motor and the outer portion disposed outside of the coils (e.g., not between the coils). As another example, the outer portion may be a portion of the heat pipe assembly that is further from the coil in the end cap heat pipe assembly, further from the magnet or conductive bar in the rotor than the inner portion, further from the rotor than the inner portion, and so on. In one embodiment, the exterior may be formed as an extension of the transformer bobbin to allow the working fluid to be removed from the transformer coil and cooled outside of the heat pipe assembly.

In one embodiment, the heat pipe assembly includes a plurality of connected walls having a porous wicking liner along the walls, an insulating layer coupled with at least one of the walls on a side of the at least one wall opposite the porous wicking liner of the at least one wall, and an interior chamber disposed within and sealed by the walls. The porous wicking liner of the wall is configured to maintain the working fluid in the internal chamber in a liquid phase. The insulating layer of at least one wall is directly against the electrically conductive member of the electromagnetic power conversion device such that heat from the electrically conductive member evaporates the working fluid in the porous wicking lining of at least one wall and the working fluid condenses at or within the porous wicking lining of at least one other wall to cool the electrically conductive member of the electromagnetic power conversion device.

Optionally, the electrically conductive member comprises one or more electrically conductive windings of the electromagnetic power conversion device, such that heat from the one or more electrically conductive windings evaporates the working fluid in the porous wicking lining of the inner wall and the working fluid condenses at or in the porous wicking lining of the outer wall to cool the one or more electrically conductive windings of the electromagnetic power conversion device.

Optionally, the wall forms an elongated interior of the internal chamber that is located between and directly adjacent to adjacent ones of the one or more conductive windings.

Optionally, the interior of the inner chamber is elongated along the axis of rotation of the electromagnetic power conversion device.

Optionally, the wall also forms an elongated exterior of the internal chamber, which is located outside the electrically conductive coil.

Optionally, the outer portion of the inner chamber is elongated in a direction perpendicular to the rotational axis of the electromagnetic power conversion device.

Optionally, the assembly further comprises an elongate fin extending outwardly from the exterior.

Optionally, the elongated outer portion of the inner chamber is elongated in a direction oriented radially towards the rotational axis of the electromagnetic power conversion device.

Optionally, the elongated outer portion of the inner chamber is elongated in a direction oriented radially away from the rotational axis of the electromagnetic power conversion device.

Optionally, the interior of the inner chamber has a rectangular cross-sectional shape in locations between adjacent conductive coils.

Optionally, the interior of the internal chamber extends between and is in contact with adjacent conductive coils on a plurality of different planes of conductive coils.

Optionally, the interior of the inner chamber has a T-shaped cross-sectional shape.

Optionally, the interior of the internal chamber is located between and in contact with opposing surfaces of adjacent electrically conductive coils that are concentrated windings of the electric motor.

Optionally, the interior of the internal chamber is located between and in contact with opposing surfaces of adjacent electrically conductive coils that are distributed windings of the electric motor.

Optionally, the interior of the inner chamber has an H-shaped cross-sectional shape.

Optionally, the assembly further comprises an end cap coupled with the conductive windings of the motor as the electromagnetic power conversion device. The wall and the inner chamber may be located within the end cap.

Alternatively, the wall is located outside and in direct contact with the stator of the motor, which is the electromagnetic power conversion device.

Optionally, the wall forms an elongate fin projecting radially away from the rotational axis of the motor, and wherein the inner chamber extends into the fin.

Optionally, the assembly further comprises a support post between the walls to structurally support the walls away from each other.

Optionally, the wall forms a rotor sleeve and an end plate as the electromagnetic power conversion device in which the rotor of the motor is located.

Optionally, a rotor sleeve formed by walls surrounds the rotor about its axis of rotation.

Optionally, the end plate formed by the wall is oriented perpendicular to the rotational axis of the rotor.

Optionally, the end plate comprises elongated fins projecting axially away from the end plate in a direction parallel to the axis of rotation. The inner chamber may extend into the elongated fin.

Optionally, the wall extends around a permanent magnet in an internal permanent magnet motor as the electromagnetic power conversion device.

Optionally, the wall extends around a magnet in an induction motor as the motor around the field of the electromagnetic power conversion device.

Optionally, the wall extends around a bobbin of a transformer as the electromagnetic power conversion device, the wall and the inner chamber being disposed between a conductive winding of the transformer and the bobbin.

Optionally, the wall forms an extension of the internal chamber that extends along the length of the bobbin but is not located between the bobbin and the conductive winding of the transformer.

In one embodiment, a heat pipe system includes a plurality of heat pipe assemblies configured to be disposed directly against an electrically conductive winding of an electric motor to cool the winding. Each of the heat pipe assemblies includes a plurality of connected walls having a porous wicking liner along the walls. The walls include at least an inner wall, an outer wall, and a connecting wall coupling the inner wall and the outer wall. Each of the heat pipe assemblies also includes an internal chamber disposed within and sealed by the wall. The porous wicking liner of the wall is configured to maintain the working fluid in the internal chamber in a liquid phase. The inner wall of the heat pipe assembly is configured to be located directly against the conductive windings of the motor such that heat from the conductive windings evaporates the working fluid in the porous wicking liner of the inner wall of the heat pipe assembly. The working fluid condenses at or within the porous wicking lining of the outer wall of the heat pipe assembly to cool the electrically conductive coil of the motor.

Optionally, the wall of the heat pipe assembly forms an elongated interior of the interior chamber that is located between and directly adjacent to adjacent ones of the one or more conductive windings. The walls of the heat pipe assembly may also form an elongated exterior of the interior chamber located outside of the conductive windings of the motor.

Optionally, the interior of the inner chamber is elongated in a direction parallel to the axis of rotation of the motor.

Optionally, the outer portion of the inner chamber is elongated in a direction perpendicular to the rotational axis of the motor.

Optionally, at least one of the heat pipe assemblies further comprises an elongated fin extending outwardly from an exterior of the heat pipe assembly.

Optionally, the electrically conductive windings of the motor extend along an annular ring around the rotational axis of the motor. The exterior of the heat pipe assembly may be located on a single side of the ring.

Optionally, the electrically conductive windings of the motor extend along an annular ring around the rotational axis of the motor. The exterior of the first set of heat pipe assemblies may be located on a first side of the ring, while the exterior of the second non-overlapping set of heat pipe assemblies may be located on an opposite second side of the ring.

Optionally, the outer portion of the heat pipe assembly is elongated in a direction oriented radially inward toward the rotational axis of the motor.

Optionally, the outer portion of the heat pipe assembly is elongated in a direction oriented radially outward toward the rotational axis of the motor.

Optionally, the heat pipe assembly automatically levels temperature differences of the conductive windings of the electric motor during operation of the electric motor by receiving more current in a first set of conductive windings and less current in a second, different set of conductive windings; the first set of electrically conductive windings is cooler because the working fluid in the respective first set of heat pipe assemblies is directed closer to the electrically conductive windings in the first set of electrically conductive windings due to one or more of gravity or acceleration forces; the second set of electrically conductive windings are hotter because the working fluid in the respective second set of heat pipe assemblies is directed to a location that is further away from the electrically conductive windings in the second set of electrically conductive windings due to one or more of gravity or acceleration forces.

Fig. 27 shows an aircraft 2700 with

propulsion systems

2702, 2704. Aircraft 2700 includes two

propulsion systems

2702, 2704, but may alternatively have a

single propulsion system

2702 or 2704, or may have more than two

propulsion systems

2702, 2704. Each

propulsion system

2702, 2704 may include an electric motor 2706 that is powered by electric current received from the same or different power sources 2708. These power sources 2708 may include batteries, fuel cells, alternators, generators, and the like. The motor 2706 includes a rotor 2710 that rotates within or relative to the stator 2712 during operation. Rotor 2710 is coupled with shaft 2714 to rotate shaft 2714. The shaft 2714 is coupled with a plurality of airfoils 2716 of an aircraft propeller 2718. Rotation of shaft 2714 by rotor 2710 also rotates airfoil 2716, which may generate thrust to move aircraft 2700.

One or more of the motors 2706 can include a heat pipe assembly 2716, the heat pipe assembly 2716 representing one or more embodiments of the heat pipe assembly described herein. For example, motor 2706 may represent motor 202 having conductive coil 200 with

heat pipe assemblies

204, 504, 804, 1204, 1304, and/or 1404. Alternatively, motor 2706 may represent motor 202 with stator 1506, with heat pipe assembly 1504. Alternatively, the motor 2706 may represent the motor 202 with the housing heat pipe assembly 1600. In another embodiment, motor 2706 may represent motor 202 with sleeve heat pipe assembly 1800. Optionally, the motor 2706 may include a rotator heat pipe assembly 2000. In another embodiment, the motor 2706 may be an induction motor with a rotor heat pipe assembly 2100. As described herein, during operation of the motor 2706, the heat pipe assembly may operate to cool the motor 2706 of the aircraft 2700.

Fig. 28 shows a power supply system 2800. The power supply system 2800 includes a power source 2802 that provides mechanical energy to a power conversion device 2804. Power source 2802 may represent an engine, turbine, or the like that rotates a shaft coupled to power conversion device 2804. The power conversion device 2804 may convert the mechanical energy to electrical energy, such as an electrical current. For example, power conversion device 2804 may represent an alternator, generator, or the like having a rotor coupled to a shaft and rotated by power source 2802. Rotation of the rotor within the stator of the power conversion device 2804 generates a current that may be provided to one or more loads 2806. The load 2806 may be an auxiliary load, such as a heating system, a cooling system, an entertainment system, a navigation system, etc., on the aircraft 2700.

The power conversion device 2804 can include one or more embodiments of the heat pipe assembly described herein. For example, the power conversion apparatus 2804 may include a conductive coil 200 having

heat pipe assemblies

204, 504, 804, 1204, 1304, and/or 1404. Optionally, the power conversion device 2804 may include a stator 1506 with a heat pipe assembly 1504. Optionally, the power conversion device 2804 may include a housing heat pipe assembly 1600. In another embodiment, the power conversion device 2804 may include a sleeved heat pipe assembly 1800. Optionally, the power conversion device 2804 may include a rotator heat pipe assembly 2000. In another embodiment, the power conversion device 2804 may include a rotator heat pipe assembly 2100. The heat pipe assembly may operate during operation to cool the power conversion device 2804.

It is to be understood that the above description is intended to be illustrative, and not restrictive. For example, the above-described embodiments (and/or aspects thereof) may be used in combination with each other. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the inventive subject matter without departing from its scope. While the dimensions and types of materials described herein are intended to define the parameters of the inventive subject matter, they are by no means limiting and are exemplary embodiments. Many other embodiments will be apparent to those of ordinary skill in the art upon reading the above description. The scope of the inventive subject matter should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. In the appended claims, the terms "including" and "in which" are used as the plain-language equivalents of the respective terms "comprising" and "wherein". Furthermore, in the appended claims, the terms "first," "second," and "third," etc. are used merely as labels, and are not intended to impose numerical requirements on their objects. Furthermore, the limitations of the following claims are not written in a "means plus function" format, nor are they to be construed based on 35 u.s.c. § 112(f), unless and until such claim limitations explicitly use the term "means for … …," followed by a functional description lacking further structure.

This written description uses examples to disclose several embodiments of the inventive subject matter, including the best mode, and also to enable any person skilled in the art to practice embodiments of the inventive subject matter, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the inventive subject matter is defined by the claims, and may include other examples that occur to those of ordinary skill in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.

The foregoing description of certain embodiments of the inventive subject matter will be better understood when read in conjunction with the appended drawings. The various embodiments are not limited to the arrangements and instrumentality shown in the drawings.

As used herein, an element or step recited in the singular and proceeded with the word "a" or "an" should be understood as not excluding plural said elements or steps, unless such exclusion is explicitly recited. Furthermore, references to "one embodiment" of the present invention are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. Furthermore, unless explicitly stated to the contrary, embodiments "comprising," "including," or "having" one or more elements having a particular property may include additional such elements having that particular property.

Claims

1. An electric motor for an aircraft, the electric motor comprising:

a stator;

2. The electric motor of claim 1, wherein one or more of the stator or the rotor includes one or more conductive windings such that heat from the one or more conductive windings vaporizes working fluid in the porous wicking lining of the at least one inner chamber wall and the working fluid condenses at or within the porous wicking lining of the at least one other inner chamber wall to cool the one or more conductive windings.

3. The electric motor of claim 2, wherein the inner chamber wall forms an elongated interior of the inner chamber that is located between and directly adjacent to adjacent ones of the one or more conductive windings.

4. The electric motor of claim 3, wherein the interior of the internal chamber is elongated along the axis of rotation of the rotor.

5. The electric motor of claim 3, wherein the inner chamber wall also forms an elongated exterior of the inner chamber that is located outside of the conductive coil.

6. The electric motor of claim 5, wherein the exterior of the interior chamber is elongated.

7. The electric motor of claim 5, further comprising elongated fins extending outwardly from the outer portion.

8. An aircraft motor comprising:

9. The aircraft motor of claim 8 wherein the inner chamber wall forms an elongated fin projecting radially away from the axis of rotation of the rotor, and wherein the inner chamber extends into the fin.

10. The aircraft motor of claim 8 further comprising support posts located between the interior chamber walls to structurally support the interior chamber walls away from each other.