Claims:WE CLAIM:
1. A cooling system (10) for an electric motor arrangement comprising:
a shaft (20) operatively coupled to a rotor (30), wherein the shaft (20) comprises a central axis (40);
at least one heat pipe (50) is enclosed within the shaft (20), wherein the at least one heat pipe (50) is parallelly positioned along the central axis (40) of the shaft (20), wherein the at least one heat pipe (50) comprises:
a first end (60); and
a second end (70),
wherein, the at least one heat pipe (50) is configured to cool the rotor (20) by spreading a coolant within an inner surface of the at least one heat pipe (50) from the first end (60) to the second end (70).
2. The system (10) as claimed in claim 1, wherein the shaft (20) is a hollow cylindrical shaft.
3. The system (10) as claimed in claim 1, wherein the at least one heat pipe comprises at least one of a plain heat pipe or a grooved heat pipe.
4. The system (10) as claimed in claim 1, wherein first end (60) acts as a heat emitting end of the at least one heat pipe (50) and the second end (70) acts as a heat absorbing end of the at least one heat pipe (50).
5. The system (10) as claimed in claim 4, wherein the heat absorbing end is configured to vaporise the coolant and the heat emitting end is configured to condense a vaporised coolant within the at least one heat pipe (50).
6. The system (10) as claimed in claim 5, wherein the coolant comprises a liquid coolant, wherein the liquid coolant comprises at least one of water, acetone, methanol and ammonia.
7. The system (10) as claimed in claim 1, wherein the at least one heat pipe (50) is configured to cool the rotor (30) by spreading the coolant within the inner surface of the at least one heat pipe (50) from the first end (60) to the second end (70) using a centrifugal force generated and preventing a formation of a plurality of droplets on the inner surface of the at least one heat pipe (50) by rotation of the shaft (20).
8. An electric vehicle system (80) comprising:
a chassis (90) configured to provide a structure to the electric vehicle;
at least one controller (100) operatively coupled within the chassis (90), and configured to control a plurality of electronic components within the electric vehicle;
an electric motor arrangement (110) placed within the chassis (90) and is operatively coupled to the at least one controller (100), wherein the electric motor arrangement (110) comprises;
a rotor (120);
a shaft (130) operatively coupled to the rotor (120), wherein the shaft (130) comprises a central axis (140);
at least one heat pipe (150) is enclosed within the shaft (130) and is parallelly positioned along the central axis (140) of the shaft (130), and configured to cool the rotor (120) by spreading a coolant (160) within an inner surface of the at least one heat pipe (150), wherein the at least one heat pipe (150) comprises:
a first end (170); and
a second end (180),
wherein, the coolant (160) evaporates at the second end (180) and the evaporated coolant (160) condenses at the first end (170).
9. The electric vehicle system (80) as claimed in claim 8, wherein the coolant (160) spreads from the first end (170) to the second end (180) within the at least one heat pipe (150).
10. The electric vehicle system (80) as claimed in claim 8, wherein the coolant (160) spreads within the inner surface of the at least one heat pipe (150) from the first end (170) to the second end (180) using a centrifugal force generated by rotation of the shaft (130).
, Description:FIELD OF INVENTION
[0001] Embodiments of the present disclosure relates to a cooling system, and more particularly to a cooling system for an electric motor.
BACKGROUND
[0002] A cooling system is a part of an electrical motor of a powertrain of an electric vehicle which is made up of one or more passages inside the powertrain of the electric vehicle. Further, the cooling system is provided with a pump to circulate a coolant inside the electrical motor through the passages provided to keep a rotor of the motor cool while the rotor is functioning.
[0003] One type of electric motor includes a plurality of concentric shafts, wherein each end of the plurality of concentric shafts includes a seal. Further, the electric motor includes an inlet valve and an outlet valve which is coupled to each of the plurality of concentric shafts. A coolant is passed through the inlet valve and is collected at the outlet valve which makes the system complex and hence bulky. Moreover, the flow of the coolant has to be maintained even at a high rotation of the rotor which can be nearly 36000 rotations per minute. In such a case, if the system fails to maintain the flow of coolant, the system shall be at a high risk.
[0004] Another type of electric motor includes heat pipes which are made up of wicking material. Further, the coolant is made to flow through the heat pipes. The coolant at a hotter end of the heat pipes vaporises and a vaporised coolant travels to a cooler end of the heat pipes and gets condensed and returns back to the hotter end due to the usage of the wicking material. However, in such system, the heat pipes have to be specially manufactured to integrate the heat pipes with the electric motor which increases the overall cost of the system. Also, the cost of the system increases due to the usage of the wicking material.
[0005] Hence, there is a need for a cooling system for an electric motor to address the aforementioned issues.

BRIEF DESCRIPTION
[0006] In accordance with one embodiment of the disclosure, a cooling system for an electric motor arrangement is provided. The system includes a shaft operatively coupled to a rotor. Further, the shaft includes a central axis. The system also includes at least one heat pipe is enclosed within the shaft. The at least one heat pipe is parallelly positioned along the central axis of the shaft. The at least one heat pipe includes a first end. The at least one heat pipe also includes a second end. The at least one heat pipe is configured to cool the rotor by spreading a coolant within an inner surface of the at least one heat pipe from the first end to the second end.
[0007] In accordance with another embodiment of the disclosure, an electric vehicle system is disclosed. The electric vehicle system includes a chassis. The chassis is configured to provide a structure to the electric vehicle. The electric vehicle system also includes at least one controller operatively coupled within the chassis. The at least one controller is configured to control a plurality of electronic components within the electric vehicle. The electric vehicle system also includes an electric motor arrangement placed within the chassis and is operatively coupled to the at least one controller. The electric motor arrangement includes a rotor. The electric motor arrangement also includes a shaft operatively coupled to the rotor. The shaft includes a central axis. The electric motor arrangement also includes at least one heat pipe is enclosed within the shaft and is parallelly positioned along the central axis of the shaft. The at least one heat pipe is configured to cool the rotor by spreading a coolant within an inner surface of the at least one heat pipe. The at least one heat pipe includes a first end. The at least one heat pipe also includes a second end. Further, the coolant evaporates at the second end and the evaporated coolant condenses at the first end.
[0008] To further clarify the advantages and features of the present disclosure, a more particular description of the disclosure will follow by reference to specific embodiments thereof, which are illustrated in the appended figures. It is to be appreciated that these figures depict only typical embodiments of the disclosure and are therefore not to be considered limiting in scope. The disclosure will be described and explained with additional specificity and detail with the appended figures.
BRIEF DESCRIPTION OF THE DRAWINGS
The disclosure will be described and explained with additional specificity and detail with the accompanying figures in which:
[0009] FIG. 1 is a schematic representation of a cooling system for an electric motor in accordance with an embodiment of the present disclosure;
[0010] FIG. 2 is a schematic cross-sectional view of at least one heat pipe enclosed in the cooling system of the electric motor of FIG. 1 in accordance with an embodiment of the present disclosure;
[0011] FIG. 3 is a schematic representation of a cooling system for an electric motor having a plurality of heat pipes of FIG. 1 in accordance with an embodiment of the present disclosure;
[0012] FIG. 4 is a schematic cross-sectional view of the plurality of heat pipes enclosed in the cooling system of the electric motor of FIG. 3 in accordance with an embodiment of the present disclosure; and
[0013] FIG. 5 is a block diagram representation of a cooling system enclosed in an electric vehicle in accordance with an embodiment of the present disclosure.
[0014] Further, those skilled in the art will appreciate that elements in the figures are illustrated for simplicity and may not have necessarily been drawn to scale. Furthermore, in terms of the construction of the device, one or more components of the device may have been represented in the figures by conventional symbols, and the figures may show only those specific details that are pertinent to understanding the embodiments of the present disclosure so as not to obscure the figures with details that will be readily apparent to those skilled in the art having the benefit of the description herein.
DETAILED DESCRIPTION
[0015] For the purpose of promoting an understanding of the principles of the disclosure, reference will now be made to the embodiment illustrated in the figures and specific language will be used to describe them. It will nevertheless be understood that no limitation of the scope of the disclosure is thereby intended. Such alterations and further modifications in the illustrated system, and such further applications of the principles of the disclosure as would normally occur to those skilled in the art are to be construed as being within the scope of the present disclosure.
[0016] The terms "comprise", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process or method that comprises a list of steps does not include only those steps but may include other steps not expressly listed or inherent to such a process or method. Similarly, one or more devices or sub-systems or elements or structures or components preceded by "comprises... a" does not, without more constraints, preclude the existence of other devices, sub-systems, elements, structures, components, additional devices, additional sub-systems, additional elements, additional structures or additional components. Appearances of the phrase "in an embodiment", "in another embodiment" and similar language throughout this specification may, but not necessarily do, all refer to the same embodiment.
[0017] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this disclosure belongs. The system, methods, and examples provided herein are only illustrative and not intended to be limiting.
[0018] In the following specification and the claims, reference will be made to a number of terms, which shall be defined to have the following meanings. The singular forms “a”, “an”, and “the” include plural references unless the context clearly dictates otherwise.
[0019] Embodiments of the present disclosure relate to a cooling system for an electric motor. The system includes a shaft operatively coupled to a rotor. Further, the shaft includes a central axis. The system also includes at least one heat pipe is enclosed within the shaft. The at least one heat pipe is parallelly positioned along the central axis of the shaft. The at least one heat pipe includes a first end. The at least one heat pipe also includes a second end. The at least one heat pipe is configured to cool the rotor by spreading a coolant within an inner surface of the at least one heat pipe from the first end to the second end.
[0020] FIG. 1 is a schematic representation of a cooling system for an electric motor in accordance with an embodiment of the present disclosure. As used herein, the electric motor is defined as an electrical machine which converts electrical energy into mechanical energy. The system (10) includes a shaft (20) operatively coupled to a rotor (30). As used herein, the shaft (20) is defined as a circular rotating object which is used to transmit energy from one part to another. Also, the rotor (30) is defined as a rotating part of an electromagnetic system of the electric motor. Further, the shaft (20) includes a central axis (40). As used herein, the central axis (40) is defined as an imaginary line at the centre of a body about which the body rotates. In one embodiment, the shaft (20) may be a hollow cylindrical shaft. In another embodiment, the shaft (20) may be enclosed at one end. In one specific embodiment, the shaft (20) may be locked to a lamination of the rotor (30).
[0021] The system (10) also includes at least one heat pipe (50). As used herein, a heat pipe is defined as a heat-transfer device which combines the principles of both thermal conductivity and phase transaction to effectively transfer the heat between two solid interfaces. Furthermore, the at least one heat pipe (50) is enclosed within the shaft (20) and is parallelly positioned along the central axis (40) of the shaft (20). In one embodiment, the at least one heat pipe (50) may be at least one of a plain heat pipe or a grooved heat pipe. In such embodiment, the plain heat pipe may be circular or elliptical in nature.
[0022] The at least one heat pipe (50) includes a first end (60). In one embodiment, the first end (60) may act as a heat emitting end of the at least one heat pipe (50). The at least one heat pipe (50) also includes a second end (70). In one embodiment, the second end (70) may act as a heat absorbing end of the at least one heat pipe (50). Also, the at least one heat pipe (50) is configured to cool the rotor (30) by spreading a coolant within an inner surface of the at least one heat pipe (50) from the first end (60) to the second end (70).
[0023] In one embodiment, a capillary limit of a diameter of each of the at least one heat pipe (50) may be reduced for the coolant to extract heat at every point of the at least one heat pipe (50). In one exemplary embodiment, the at least one heat pipe (50) may be circular in shape. In another exemplary embodiment, the at least one heat pipe (50) may be elliptical in shape.
[0024] In such embodiments, the heat absorbing end may be configured to vaporise the coolant and the heat emitting end may be configured to condense a vaporised coolant within the at least one heat pipe (50). In one embodiment, the coolant may be at least one of water, acetone, methanol and ammonia. In one exemplary embodiment, the first end (60) of the at least one heat pipe (50) may be extended along the shaft (20) and may be operatively coupled to a cooling subsystem (not shown). The cooling subsystem may be configured to condense the vaporised coolant within the at least one heat pipe (50). In one embodiment, the cooling subsystem may be at least one of a liquid cooling subsystem, an air cooling subsystem and the like.
[0025] In one specific embodiment, the at least one heat pipe (50) may be configured to cool the rotor (30) as the coolant spreads on the inner surface of the at least one heat pipe from the first end (60) to the second end (70) due to a centrifugal force generated henceforth preventing a formation of plurality of droplets on the inner surface of the at least one heat pipe (50) upon the rotation of the shaft (20). As used herein, the centrifugal force is defined as a force which is generated by a body due to inertia of the body, which tends to appear on a moving body in a circular path and is directed away from centre around the body when in motion. Furthermore, the coolant may flow from the first end (60) to the second end (70) and may get evaporated at the second end (70). Further, the evaporated coolant may flow back to the first end (60) and may get condensed. The condensed coolant tends to flow back to the second end (70), thereby keeping the process continuous.
[0026] In operation, as the rotor (30) of the electric motor is in operation, the shaft (20) coupled to the rotor (30) also rotates. As the power produced by the motor is high, an enormous amount of heat is generated in the rotor (30). In order to transfer the heat generated in the rotor (30) away from the system (10), the at least one heat pipe (50) is enclosed within the shaft (20) and is parallelly positioned along the central axis (40) of the shaft (20). wherein the at least one heat pipe (50) is filled with the coolant such as water. Further, as the coolant approaches the second end (70), the heat generated in the rotor (30) is absorbed by the coolant. The coolant tends to move from the first end (60) to the second end (70) due to the centrifugal force generated by the rotation of the shaft (20), henceforth preventing the formation of the plurality of droplets within the inner surface of the at least one shaft (50). Furthermore, due to the heat absorption at the second end (70), the coolant gets evaporated.
[0027] Furthermore, the evaporated coolant tends to flow towards the first end (60) of the at least one heat pipe (50). Further, as the evaporated coolant approaches the first end (60), the at least one heat pipe (50) at the first end (60) is exposed to the cooling subsystem which manages to cool the evaporated coolant, thereby the evaporated coolant tends to condense at the first end (60) of the at least one heat pipe (50). Further, the condensed coolant tends to flow toward the second end (70) again due to the continuous rotation of the shaft (20) and hence due to the centrifugal force produced by the shaft (20). Henceforth, the process is cyclic, thereby continuously removing the heat generated in the rotor (30).
[0028] FIG. 2 is a schematic cross-sectional view of the at least one heat pipe enclosed in the cooling system of the electric motor of FIG. 1 in accordance with an embodiment of the present disclosure. FIG. 2a represents the cross-section view (71) of the first end (60) of the at least one heat pipe (50) enclosed within the shaft (20) and is parallelly positioned along the central axis of the shaft (20). FIG. 2b represents the cross-sectional view (71) of the second end (70) of the at least one heat pipe (50) enclosed within the shaft (20). Further, the at least one heat pipe (50) in the FIG. 2a and the FIG. 2b are circular in nature.
[0029] FIG. 2c represents the cross-section view (71) of the first end (60) of the at least one heat pipe (50) enclosed within the shaft (20) and is parallelly positioned along the central axis of the shaft (20). FIG. 2d represents the cross-sectional view (71) of the second end (70) of the at least one heat pipe (50) enclosed within the shaft (20). Further, the at least one heat pipe (50) in the FIG. 2c and the FIG. 2d are grooved in nature.
[0030] FIG. 3 is a schematic representation of a cooling system for an electric motor having a plurality of heat pipes of FIG. 1 in accordance with an embodiment of the present disclosure. The at least one heat pipe (50) includes a plurality of heat pipes (50) is enclosed within the shaft (20) and is parallelly positioned along the central axis (40) of the shaft (20). FIG. 3 shows two heat pipes (51, 54) of the plurality of heat pipes (50), wherein the other plurality of heat pipes (not shown in FIG. 3) are positioned parallelly along the central axis (40) of the shaft (20).
[0031] Furthermore, the plurality of heat pipes (50) are positioned parallel to each other along the central axis (40). The plurality of heat pipes (50) includes a first end (60) which acts as a heat emitting end of the plurality of heat pipes (50). The plurality of heat pipes (50) also includes a second end (70) which acts as a heat absorbing end of the plurality of heat pipes (50). Also, the plurality of heat pipes (50) is configured to cool the rotor (30) by spreading a coolant within an inner surface of the plurality of heat pipes (50) from the first end (60) to the second end (70).
[0032] Furthermore, the heat absorbing end is configured to vaporise the coolant and the heat emitting end is configured to condense a vaporised coolant within the plurality of heat pipes (50). In one embodiment, the coolant may be at least one of water, acetone, methanol and ammonia. In one exemplary embodiment, the first end (60) of the at least one heat pipe (50) may be extended along the shaft (20) and may be operatively coupled to a cooling subsystem (not shown). The cooling subsystem may be configured to condense the vaporised coolant within the plurality of heat pipes (50). In one embodiment, the cooling subsystem may be at least one of a liquid cooling subsystem, an air cooling subsystem and the like.
[0033] In one specific embodiment, the plurality of heat pipes (50) may be configured to cool the rotor (30) as the coolant spreads on the inner surface of the plurality of heat pipes (50) from the first end (60) to the second end (70) due to the centrifugal force generated, henceforth preventing the formation of the plurality of droplets on the inner surface of the plurality of heat pipes (50) upon the rotation of the shaft (20).
[0034] FIG. 4 is a schematic cross-sectional view of at least one heat pipe enclosed in the cooling system of the electric motor of FIG. 3 in accordance with an embodiment of the present disclosure. FIG. 4a represents the cross-section view (71) of the first end (60) of the plurality of heat pipes (51, 52, 53, 54, 55, 56) enclosed within the shaft (20) and is parallelly positioned along the central axis of the shaft (20). FIG. 4b represents the cross-sectional view (71) of the second end (70) of the plurality of heat pipes (51, 52, 53, 54, 55, 56) enclosed within the shaft (20). Further, the plurality of heat pipes (51, 52, 53, 54, 55, 56) in the FIG. 4a and the FIG. 4b are circular in nature.
[0035] Further, FIG. 4c represents the cross-sectional view (71) of the first end (60) of the plurality of heat pipes (51, 52, 53, 54, 55, 56) enclosed within the shaft (20) and is parallelly positioned along the central axis of the shaft (20). FIG. 4d represents the cross-sectional view (71) of the second end (70) of the plurality of heat pipes (51, 52, 53, 54, 55, 56) enclosed within the shaft (20). Further, the plurality of heat pipes (51, 52, 53, 54, 55, 56) in the FIG. 4c and the FIG. 4d are elliptical in nature.
[0036] Further, FIG. 4e represents the cross-sectional view (71) of the first end (60) of the plurality of heat pipes (51, 52, 53, 54, 55, 56) enclosed within the shaft (20) and is parallelly positioned along the central axis of the shaft (20). FIG. 4f represents the cross-sectional view (71) of the second end (70) of the plurality of heat pipes (51, 52, 53, 54, 55, 56) enclosed within the shaft (20). Further, the plurality of heat pipes (51, 52, 53, 54, 55, 56) in the FIG. 4e and the FIG. 4f are grooved in nature
[0037] FIG. 5 is a block diagram representation of a cooling system enclosed in an electric vehicle in accordance with an embodiment of the present disclosure. As used herein, the electric vehicle is defined as a vehicle which uses one or more electric motors for propulsion of the electric vehicle. The electric vehicle system (80) includes a chassis (90). As used herein, the chassis (90) is defined as a base frame of a wheeled vehicle. The chassis (90) is configured to provide a structure to the electric vehicle. The electric vehicle system (80) also includes at least one controller (100) operatively coupled within the chassis (90). The at least one controller (100) is configured to control a plurality of electronic components within the electric vehicle.
[0038] Furthermore, the electric vehicle system (80) also includes an electric motor arrangement (110) placed within the chassis (90) and is operatively coupled to the at least one controller (100). The electric motor arrangement (110) includes a rotor (120). The electric motor arrangement (110) also includes a shaft (130) operatively coupled to the rotor (120). In one embodiment, the shaft (130) may be a hollow cylindrical shaft. Further, the shaft (130) includes a central axis (140).
[0039] The electric vehicle system (80) also includes at least one heat pipe (150) enclosed within the shaft (130) along the central axis (140) of the electric motor arrangement (110). The at least one heat pipe (150) is parallelly positioned along the central axis (140) of the shaft (130). In one embodiment, the at least one heat pipe (150) may be a plain heat pipe or a grooved heat pipe. In such embodiment, the plain heat pipe may be circular or elliptical in nature.
[0040] The at least one heat pipe (150) is configured to cool the rotor (120) by spreading a coolant (160) within an inner surface of the at least one heat pipe (150). In one embodiment, the coolant (160) may be at least one of water, acetone, methanol and ammonia. In another embodiment, the at least one heat pipe (150) may be at least one of circular heat pipe, oval heat pipe and elliptical heat pipe.
[0041] Furthermore, the at least one heat pipe (150) includes a first end (170). In one embodiment, the first end (170) may act as a heat emitting end of the at least one heat pipe (150). The at least one heat pipe (150) also includes a second end (180). In one embodiment, the second end (180) may act as a heat absorbing end of the at least one heat pipe (150). Also, a distance between the central axis (140) and an external surface of the at least one heat pipe (150) at the first end (170) is equal to the distance between the central axis (140) and the external surface of the corresponding at least one heat pipe (150) at the second end (180). Further, the at least one heat pipe (150) is configured to cool the rotor (120) by spreading the coolant (160) within the inner surface of the at least one heat pipe (150) from the first end (170) to the second end (180) of the at least one heat pipe (150). In such embodiment, the coolant (160) may spread within the inner surface of the at least one heat pipe (150) from the first end (170) to the second end (180) using a centrifugal force generated by rotation of the shaft (130).
[0042] In one embodiment, the vaporised coolant (160) may spread from the second end (180) to the first end (170) within the at least one heat pipe (150). Further, the second end (180) of the at least one heat pipe (150) may be configured to vaporise the coolant (160) by absorbing the heat generated in the rotor (120) upon rotation. Furthermore, the coolant (160) evaporates at the second end (180) and the evaporated coolant (160) condenses at the first end (170). In such embodiment, the evaporated coolant which may spread from the second end (180) to the first end (170). Consequently, the vaporised coolant (160) may get condensed within the first end (170) of the at least one heat pipe (150).
[0043] Various embodiments of the cooling system for an electric motor enables the system to maintain a constant flow of coolant within the at least one heat pipe even at high rotations per minute. Hence making the system highly efficient. Also, due to the structure of the heat pipe which may be plain or grooved and the centrifugal force generated, the cooling process of the rotor is enhanced. In addition, due to the use of the plain or grooved heat pipes, the overall cost of the system is reduced.
[0044] Further, due to the constant distance from the central axis to the external surface from one end of the at least one heat pipe to the other end of the at least one heat pipe, the exchange of the heat generated in the rotor is more efficient and faster. Also, due to the centrifugal force being used, the at least one heat pipe works as thermosyphons.
[0045] While specific language has been used to describe the disclosure, any limitations arising on account of the same are not intended. As would be apparent to a person skilled in the art, various working modifications may be made to the method in order to implement the inventive concept as taught herein.
[0046] The figures and the foregoing description give examples of embodiments. Those skilled in the art will appreciate that one or more of the described elements may well be combined into a single functional element. Alternatively, certain elements may be split into multiple functional elements. Elements from one embodiment may be added to another embodiment. For example, order of processes described herein may be changed and are not limited to the manner described herein. Moreover, the actions of any flow diagram need not be implemented in the order shown; nor do all of the acts need to be necessarily performed. Also, those acts that are not dependant on other acts may be performed in parallel with the other acts. The scope of embodiments is by no means limited by these specific examples.