FORM2
THE PATENTS ACT 1970
39 OF 1970
&
THE PATENT RULES 2003
COMPLETESPECIFICATION
(SEE SECTIONS 10 & RULE 13)
1. TITLEOF THE INVENTION “AN INTEGRATED ASSEMBLY FOR IMPROVING HEAT DISSIPATION IN MOTOR ASSEMBLY OF A VEHICLE”

2. APPLICANTS (S)
(a) Name:
(b) Nationality:
(c) Address:

Varroc Engineering Limited
Indian
L-4, Industrial Area,
Waluj MIDC, Aurangabad-431136,
Maharashtra, India

3. PREAMBLETOTHEDESCRIPTION
COMPLETESPECIFICATION
The following specification particularly describes the invention and the manner in which it is to be performed.

FIELD OF THE INVENTION
[001] The present invention generally relates to a vehicle motor assembly, and more particularly relates to an integrated assembly with a unique design and construction for improving heat dissipation in the motor assembly of vehicles, such as, electric vehicles.
BACKGROUND OF THE INVENTION
[002] Electric vehicles (EVs) are gaining popularity among masses with the advent and modernization of such vehicles. Due to ever increasing demand of EVs in the market, the power requirement of a traction motor (used for propulsion of such electric vehicles) has also increased. Although, certain customers are still habituated to long ranges with the conventional Internal Combustion (IC) based vehicles, however, with the advancement in the traction motors of such electric vehicles, there is a lot of potential to attract more customers to use electric vehicles. One aspect which has the potential to increase the performance of EVs is cooling of the traction motor.
[003] Cooling is a critical design consideration for traction motors in EVs. The high-power densities of these motors can generate significant amounts of heat which may lead to demagnetization of magnet (used in rotor), and therefore a system must be designed to effectively dissipate this heat to prevent overheating and maintain the efficiency of the motor. The basic components of an EV traction motor include a rotor (rotating part) and a stator (stationary part). The stator contains windings that generate a magnetic field when supplied with electric current. The rotor, which is attached to the drive shaft of the vehicle, contains a set of permanent magnets. When the magnetic field generated by the rotor, it interacts with the magnetic field of the stator assembly, causing rotor assembly to rotate as well. The interaction of the magnetic fields between the rotor and the stator is what generates the torque required to propel the vehicle. In the existing designs, an internal traction motor fan is installed in a rotor’s rear-end of the traction motor to circulate the air for cooling the traction motor. The fan is used only to create turbulence inside the traction motor which causes noise and drag to the rotating component. Further, the cooling efficiency of the fan is usually insignificant. In order to overcome the aforementioned problems and for cooling of the traction motor, various fans and associated designs for supporting of fans have been devised to reduce fan-generated noise and to move air more efficiently. Also, various modified fan blade designs have been
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conventionally deployed in order to reduce noise and increase efficiency, but none of these existing designs are able to flow the air across rotating part of the traction motor.
[004] In the existing literature, US 09/723,498 dated November 28, 2000 titled “Slip ring end (SRE) fan having coil lead retention feature” discloses a fan for a dynamoelectric machine wherein said dynamoelectric machine includes a rotor with a rotatable shaft, said fan comprising a hub having a central aperture configured to accommodate said shaft. In this document, the construction and design of the fan is totally different. The fan is designed in such a way that the blades of the fan have decreasing thickness towards a radially distal edge in order to improve rigidity and to decrease flexing and oscillation of the fan during use. In addition to this, the design is used only for creating swirling or turbulence in available space and not to dissipate the generated heat. Overall, the objective of dissipation of heat is not achieved by the designing of the fan in the cited document.
[005] Currently, there is a very limited application of internal rotor fan in traction motor domain. Few fans are designed using plastic and sheet metal as construction material which leads to bulkiness. Further, some fans are designed to circulate air for limited space which causes uneven heat dissipation which leads to non-uniform temperature distribution. Other alternatives like oil cooling and forced air cooling have been tried to overcome unequal heat dissipation, however, all such conventional solutions lead to extra cost, weight, and bulk packaging.
[006] Therefore, a solution is required to overcome the aforesaid problems and costly alternatives. The cooling of the traction motor has the potential to increase the performance, hence, a solution is required which can cool down (lower the temperature) the motor of an electric vehicle by dissipating heat effectively, is compact in design, has lower cost, high-efficiency, and can be easily manufactured.
SUMMARY AND OBJECTIVES OF THE INVENTION
[007] The following presents a simplified summary of the subject matter in order to provide a basic understanding of some aspects of the embodiments of the present invention. This summary is not an extensive overview of the subject matter. It is not intended to identify key/critical elements of the embodiments or to delineate the scope of the subject matter.
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[008] The primary objective of the present invention is to provide an integrated assembly which is a combination of aero-foil fan shaped blades uniquely integrated over the rotor end plate of the motor of an electric vehicle.
[009] In an aspect, a motor assembly is disclosed. The motor assembly comprises a stator assembly and a rotor assembly magnetically coupled with the stator assembly, the rotor assembly comprising a rotor duct configured to allow flow of air there-between. The motor assembly comprises a fan assembly coupled to the rotor assembly, the fan assembly comprising a rotor end plate and a plurality of aero-foil blades integrated with the rotor end plate at pre-defined angles. The plurality of aero-foil blades are configured to generate an airflow into the rotor duct based on the pre-defined angles upon rotation of the rotor assembly and the fan assembly, thereby enabling heat dissipation in the motor assembly during operation of the rotor assembly.
[010] In an embodiment, the plurality of aero-foil blades are integrated with the rotor end plate at a predetermined distance with respect to each other.
[011] In an embodiment, the fan assembly comprises a plurality of holes configured to receive corresponding nuts for fixedly coupling the fan assembly with the rotor assembly, wherein rotation of the rotor assembly causes simultaneous rotation of the fan assembly.
[012] In an embodiment, each of the plurality of holes is alternatively positioned between a corresponding pair of aero-foil blades amongst the plurality of aero-foil blades.
[013] In an embodiment, the plurality of aero-foil blades include a first type of blades and a second type of blades, and wherein the first type of blades have a chord line length smaller that a chord line length of the second type of blades.
[014] In an embodiment, the first type of blades and the second type of blades are alternatively integrated on the rotor end plate.
[015] In an embodiment, the plurality of aero-foil blades are configured to generate an airflow in a closed-loop within the rotor duct of the rotor assembly.
[016] In an embodiment, each of the plurality of aero-foil blades has a blade thickness of 3.5mm, and wherein the rotor end plate has a thickness of 3mm.
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[017] Another objective of the present invention is to provide a uniquely designed and constructed aero-foil blade in order to dissipate the heat more effectively and address de¬magnetization issue in traction motor application.
[018] Yet another objective of the present invention is to provide a cost-effective, highly efficient 3-dimensional aero-foil fan design as per the space available in the traction motor assembly after potting.
[019] Yet another objective of the present invention is to provide aero-foil fan blades, wherein the position of blades is designed in such a way that all air flow can access maximum pocket area in lamination stack.
[020] Yet another objective of the present invention is to provide aero-foil fan blades with nuts affixed to the rotor end plate and positioned alternatively after every two blades of the integrated assembly.
[021] Yet another objective of the present invention is to validate the design of aero-foil through Computational Fluid Dynamics (CFD) to study and analyse the effect of air flow on surrounding objects.
[022] The invention now will be described more fully hereinafter with reference to the accompanying drawing, which is intended to be read in conjunction with both this summary and objective of the invention, the detailed description and any preferred and/or particular embodiments specifically discussed or otherwise disclosed. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided by way of illustration only and so that this disclosure will be thorough, complete and will fully convey the full scope of the invention to those skilled in the art.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention may be better understood, and its numerous objects, features, components and advantages are made apparent to those skilled in the art, by referring to the accompanying drawing, in which:
Figure 1A illustrates a side view of a rotor assembly.
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Figures 1B illustrates cross-sectional view of the rotor assembly, the cross-section being taken along the line A-A.
Figures 1C illustrates cross-sectional view of a motor assembly including the rotor assembly.
Figure 1D illustrates a rotor assembly and the fan assembly associated with the motor assembly.
Figure 1E illustrates the rotor assembly and the fan assembly when viewed from direction A.
Figures 2A-2C illustrate various views of the fan assembly.
Figures 2D-2E illustrate exemplary configurations of the fan assembly.
Figure 3 illustrates the aero-foil shape of an aero-foil blade among the plurality of aero-foil blades.
Figure 4 represents an air domain associated with the motor assembly representing empty space inside the motor assembly where the air circulates.
Figures 5A-5B depict a comparison of temperature contouring on the air domain of a conventional motor assembly and the air domain of the motor assembly integrated with the fan assembly.
Figures 6A-6B depict a comparison of heat maps associated with a conventional motor assembly and heat map associated with the motor assembly.
Figure 7 depicts the effect of the fan assembly on the temperature and flow through Rotor cooling Computational Fluid Dynamics (CFD) analysis.
[023] Further, skilled artisans will appreciate that elements in the drawings are illustrated for simplicity and may not have been necessarily 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 drawings by conventional symbols, and the drawings may show only those specific details that are pertinent to understanding the embodiments of the present disclosure so as not to obscure the drawings with details that will be readily apparent to those of ordinary skill in the art having benefit of the description herein.
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DETAILED DESCRIPTION OF THE INVENTION
[024] The following description describes various features and functions of the disclosed device with reference to the accompanying figures The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the present invention.
[025] The detailed description is construed as a description of the currently preferred embodiments of the present invention and does not represent the only form in which the present invention may be practiced. This is to be understood that the same or equivalent functions may be accomplished, in any order unless expressly and necessarily limited to a particular order, by different embodiments that are intended to be encompassed within the scope of the present invention.
[026] The embodiment is chosen and described to provide the best illustration of the principles of the invention and its practical application and to enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skilled in the art to which this disclosure belongs. The system, methods, and examples provided herein are illustrative only and not intended to be limiting.
[027] The term “some” as used herein is defined as “none, or one, or more than one, or all.” Accordingly, the terms “none,” “one,” “more than one,” “more than one, but not all” or “all” would all fall under the definition of “some.” The term “some embodiments” may refer to no embodiments or to one embodiment or to several embodiments or to all embodiments. Accordingly, the term “some embodiments” is defined as meaning “no embodiment, or one embodiment, or more than one embodiment, or all embodiments.”
[028] The terminology and structure employed herein is for describing, teaching and illuminating some embodiments and their specific features and elements and does not limit, restrict or reduce the spirit and scope of the claims or their equivalents.
[029] More specifically, any terms used herein such as but not limited to “includes,” “comprises,” “has,” “consists,” and grammatical variants thereof do NOT specify an exact limitation or restriction and certainly do NOT exclude the possible addition of one
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or more features or elements, unless otherwise stated, and furthermore must NOT be taken to exclude the possible removal of one or more of the listed features and elements, unless otherwise stated with the limiting language “MUST comprise” or “NEEDS TO include.”
[030] Whether or not a certain feature or element was limited to being used only once, either way it may still be referred to as “one or more features” or “one or more elements” or “at least one feature” or “at least one element.” Furthermore, the use of the terms “one or more” or “at least one” feature or element do NOT preclude there being none of that feature or element, unless otherwise specified by limiting language such as “there NEEDS to be one or more . . .” or “one or more element is REQUIRED.”
[031] Unless otherwise defined, all terms, and especially any technical and/or scientific terms, used herein may be taken to have the same meaning as commonly understood by one having an ordinary skill in the art.
[032] Reference is made herein to some “embodiments.” It should be understood that an embodiment is an example of a possible implementation of any features and/or elements presented in the attached claims. Some embodiments have been described for the purpose of illuminating one or more of the potential ways in which the specific features and/or elements of the attached claims fulfil the requirements of uniqueness, utility and non-obviousness.
[033] Use of the phrases and/or terms such as but not limited to “a first embodiment,” “a further embodiment,” “an alternate embodiment,” “one embodiment,” “an embodiment,” “multiple embodiments,” “some embodiments,” “other embodiments,” “further embodiment”, “furthermore embodiment”, “additional embodiment” or variants thereof do NOT necessarily refer to the same embodiments. Unless otherwise specified, one or more particular features and/or elements described in connection with one or more embodiments may be found in one embodiment, or may be found in more than one embodiment, or may be found in all embodiments, or may be found in no embodiments. Although one or more features and/or elements may be described herein in the context of only a single embodiment, or alternatively in the context of more than one embodiment, or further alternatively in the context of all embodiments, the features and/or elements may instead be provided separately or in any appropriate combination or not at all. Conversely, any features and/or elements described in the context of separate
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embodiments may alternatively be realized as existing together in the context of a single embodiment.
[034] Any particular and all details set forth herein are used in the context of some embodiments and therefore should NOT be necessarily taken as limiting factors to the attached claims. The attached claims and their legal equivalents can be realized in the context of embodiments other than the ones used as illustrative examples in the description below.
[035] Embodiments of the present disclosure will be described below in detail with reference to the accompanying drawings.
[036] Referring to Figures 1A-1C, the present disclosure describes a motor assembly 100. The motor assembly 100 comprises a rotor assembly 101. Figures 1A-1B illustrates various views of the rotor assembly 101. The motor assembly 100 may form part of a traction motor. The motor assembly along with the traction motor may be configured to be integrated with a vehicle (not shown), such as an electric vehicle. In non-limiting examples, the traction motor may be a brushless motor, an inverter-fed synchronous motor, a permanent magnet synchronous motor (PMSM), and the like. In an embodiment, the motor assembly 100 may have a rotating speed of more than 7500 rpm, a rated speed of more than 4000 rpm, and peak power 3 times higher than the rated speed.
[037] Figures 1C illustrates cross-sectional views of the motor assembly 100. The motor assembly comprises the rotor assembly 101 and a stator assembly 102. The motor assembly 100 operates on the principle of electromagnetism to convert electrical energy into mechanical motion, thereby providing the necessary propelling power to run the vehicle.
[038] The stator assembly 102 is a stationary assembly that encompasses the rotor assembly 101. The stator assembly 102 may be formed of a core made of laminated steel sheets, around which coils of wire are wound. The coils of wire may be referred to as stator windings 103. The stator windings 103 may allow the flow of electric current which produces a magnetic field. The primary function of the stator assembly 102 is to generate the magnetic field that interacts with the rotor assembly 101 to produce a rotational motion. The core made of the laminated steel sheets not only provide structural support
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but also allows the magnetic fields (flux) generated by the stator windings 103 to be concentrated. In an embodiment, the stator windings may be formed of copper which allows efficient electrical conductivity, thereby causing efficient energy transfer and effective generation of magnetic fields.
[039] The rotor assembly 101 is a moving part of the motor assembly 100. The rotor assembly 101 may be mounted within the stator assembly 102. The rotor assembly 101 may be configured to freely rotate around a corresponding axis of rotation. The rotor assembly 101 may be configured to interact with the magnetic field produced by the stator assembly 102 in order to produce a mechanical motion (in this case, rotational motion). In an embodiment, the rotor assembly 101 may include permanent magnets. In another embodiment, the rotor assembly 101 may include electromagnets.
[040] In an embodiment, when the motor assembly 100 is integrated with electric vehicles, the rotor assembly 101 may include permanent magnets 104 made of materials such as neodymium or samarium-cobalt, thereby providing a strong magnetic field that interacts with the magnetic field of the stator assembly 102 to produce rotational motion. The rotor assembly 101 may thus be magnetically coupled with the stator assembly 102.
[041] The motor assembly 100 may further include a bus-bar assembly 105 configured to channel electrical power to various components within the motor assembly 100, including the stator windings 103 and other control electronics. The bus-bar assembly 105 may be made from conductive materials such as copper or aluminum to ensure efficient power transmission and management. The motor assembly 100 may further include sensor printed circuit boards (PCBs) 106 associated with multiple sensors used to monitor and control various parameters of the operation of the motor assembly 100, such as speed, position, and temperature. The sensors provide critical data to the control electronics associated with the motor assembly 100, enabling precise control and optimization of performance.
[042] The motor assembly 100 may further include wiring harness 107 comprising insulated wires and connectors bundled together to transmit electrical signals between different motor components, including sensors, controllers, and power sources. This structured assembly ensures reliable operation while minimizing the risk of electrical faults. The motor assembly 100 may further include rear end-shield assembly 108
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positioned at rear side of the motor assembly 100 and serving as a protective housing to safeguard internal components from environmental hazards such as dust, debris, and moisture. Additionally, the rear end-shield assembly 108 may also help in heat dissipation and contribute to the overall structural integrity of the motor assembly 100.
[043] The motor assembly 100 may further include an oil seal 109 configured to prevent the leakage of oil or lubricant from the internal components of the motor assembly 100, such as bearings or gears. The oil seal facilitates in maintaining proper lubrication levels within the motor assembly 100 while preventing contaminants from entering internal areas. This enhances the motor's efficiency, reliability, and lifespan by reducing friction and wear on moving parts.
[044] The motor assembly 100 may further include an enclosure 110 that acts as a protective casing for the internal components. The enclosure 110 shields the motor assembly 100 from environmental factors like dust, moisture, and debris, while also providing mechanical protection against impacts and vibrations. The enclosure helps maintain the motor's integrity and ensures reliable operation in various operating conditions.
[045] The rotor assembly 101 may be coupled to an output shaft associated with the motor assembly 100, which allows transfer of the rotational motion of the rotor assembly 101 to other components, such as, wheels. The rotational motion of the rotor assembly 101 may also be transferred to a cooling mechanism, such as fan blades, as will be described further below. In particular, the motor assembly 100 may comprise a fan assembly 150 configured to facilitate heat dissipation during operation of the motor assembly 100.
[046] Figure 1D illustrates a rotor assembly 101 and the fan assembly 150 associated with the motor assembly 100. Figure 1E illustrates the rotor assembly 101 and the fan assembly 150 when viewed from direction A. The rotor assembly 101 may be comprise a rotor duct configured to allow flow of air there-between. The fan assembly 150 may comprise a rotor end plate 151 and a plurality of aero-foil blades 152 integrated with the rotor end plate 151 at pre-defined angles. The plurality of aero-foil blades 152 are configured to generate an airflow into the rotor duct based on the pre-defined angles when
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the rotor assembly 101 and the fan assembly 150 are in rotation, thereby enabling heat dissipation in the motor assembly 100 during operation of the rotor assembly 101.
[047] Figures 2A-2C illustrate various views of the fan assembly 150. Further, Figures 2D-2E illustrate an exemplary configuration of the fan assembly 150, in that, Figure 2D depicts the fan assembly from a front side (facing away from the rotor assembly 101) while Figure 2E illustrates the fan assembly from a rear side (facing the rotor assembly 101). For sake of brevity, Figures 2A-2E are explain together for sake of brevity.
[048] The fan assembly 150 comprises the rotor end plate 151 and the plurality of aero-foil blades 152. As seen at least in Figures 2B and 2D, the plurality of aero-foil blades 152 are integrated with the rotor end plate 151. In an embodiment, the rotor end plate 151 and the plurality of aero-foil blades 152 may be manufactured as a single, uniform element. In an embodiment, the rotor end plate 151 and the plurality of aero-foil blades 152 may be manufactured separately and fixedly integrated to form the fan assembly 150.
[049] The plurality of aero-foil blades 152 are positioned at the rotor end plate 151 at a predetermined distance with respect to each other. In particular, the plurality of aero-foil blades 152 are integrated at a pre-defined angle and pre-defined distances with respect to each other. The pre-defined angle may be calculated so as to generate an airflow into the rotor duct in order to facilitate heat dissipation during operation of the motor assembly 100.
[050] In a non-limiting embodiment, the plurality of aero-foil blades 152 may include 10 blades, each blade arranged at a calculated angle on the rotor end plate 151. Referring to Figure 3, the aero-foil shape of an aero-foil blade among the plurality of aero-foil blades 152 is depicted. The aero-foil shape may be a streamlined shape specifically designed to produce a desirable aerodynamic effect when it interacts with air. In an embodiment, the aero-foil shape may be characterized by a curved profile which is asymmetrical. In an embodiment, the aero-foil shape may have a longer and more curved upper surface compared to the lower surface. This facilitates smooth airflow over the top of the aero-foil blade.
[051] The aero-foil blade as depicted in Figure 3 may have a leading edge 301 and a trailing edge 302. The leading edge 301 is the front edge of the aero-foil blade where
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airflow initially encounters the blade. The leading edge 301 may be rounded to minimize drag. The trailing edge 302 may be the rear edge of the aero-foil blade. The trailing edge 302 may be tapered.
[052] A chord line 303 may refer to a straight line that connects the leading edge 301 to the trailing edge 302. The chord line 303 may serve as a reference line for measuring various aerodynamic properties, such as the angle of attack and the dimensions of the blade. Arrow 304 depicts the relative airflow direction and numeral 305 depicts the angle of attack, i.e., the angle between the chord line 303 of the blade and the direction of the oncoming airflow 304. The angle of attack 305 defines how the airflow interacts with the blade. Based on the angle of attack 305, the airflow direction into the rotor duct can be adjusted as per the requirements.
[053] A mean camber line 306 refers to a line that runs along the midpoint between the upper and lower surfaces of the blade, representing an average curvature of the blade. Numeral 307 depicts a camber that defines the curvature of the blade while numeral 308 depicts a chord that defines a straight-line distance between the leading edge 301 and the trailing edge 302, measured along the chord line 303. Further, numeral 309 depicts a thickness of the blade, i.e., distance between upper and lower surfaces of the blade at a particular point, measured perpendicular to the chord line 303.
[054] Referring again to Figures 2D-2E, the rotor end plate 151 may comprise a plurality of holes 153 configured to receive corresponding nuts 154 for fixedly coupling the fan assembly 150 with the rotor assembly 101. The rotation of the rotor assembly 101 thus causes simultaneous rotation of the fan assembly 150. The nuts 154 are visible in Figure 2C and the fan assembly 150 coupled to the rotor assembly 101 is visible in Figures 2A-2B.
[055] In an embodiment, each of the plurality of holes 153 is alternatively positioned between a corresponding pair of aero-foil blades amongst the plurality of aero-foil blades 152. For instance, as seen in Figure 2D, hole 153a is positioned between blades 152a and 152b. Similarly, each of the plurality of holes 153 is alternatively positioned between a corresponding pair of aero-foil blades.
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[056] In an embodiment, each of the plurality of aero-foil blades 152 has a blade thickness of around 3.5mm. In an embodiment, the rotor end plate 151 has a thickness of around 3mm. That is the design of each of the aero-foil blade may be forwardly curved with blade thickness around 3.5mm. In an embodiment, the weight of the integrated fan assembly 150 may be similar to end plates of conventional motors in order to minimize the balance of the rotor assembly 101.
[057] In an embodiment, each of the plurality of aero-foil blades 152 may be of same size, shape, and configuration. The plurality of aero-foil blades 152 may be arranged at different angles with respect to each other, however, each of the plurality of aero-foil blades 152 may be of the same shape and size. As an example, Figures 2B-2C depict the plurality of aero-foil blades 152 having the same shape and size.
[058] In another embodiment, the plurality of aero-foil blades 152 include a first type of blades and a second type of blades. The first type of blades may have a different shape and size as compared to the second type of blades. For instance, the first type of blades may have a chord line length smaller that a chord line length of the second type of blades. As an example, Figure 2D depicts the plurality of aero-foil blades 152 having a first type of blades and a second type of blades, in that, the first type of blades are labelled as 152a, 152c, 152e, 152g, 152i and the second type of blades are labelled as 152b, 152d, 152f, 152h, 152j. The first and second type of blades allow a proper fixing of the nuts 154 into the holes 153 in view of the space available on the rotor end plate 151. In an embodiment, as seen in Figure 2D, the first type of blades and the second type of blades are alternatively integrated on the rotor end plate 151.
[059] The position selection of the plurality of aero-foil blades may thus depend on space availability to incorporate the blades and the amount of static air affected.
[060] As described above, the plurality of aero-foil blades 152 are integrated with the rotor end plate 151 at predetermined calculated angles. The positioning of the aero-foil blades 152 at the calculated angles enable air flow to access maximum area in the rotor duct and the lamination stack.
[061] Figure 4 represents an air domain associated with the motor assembly 100 representing empty space inside the motor assembly 100 where the air circulates. In
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operation, rotation of the rotor assembly 101 causes simultaneous rotation of the fan assembly 150, i.e., the rotor end plate 151 and the plurality of integrated aero-foil blades 152. When the plurality of aero-foil blades 152 rotate, the surrounding static air collides with the plurality of aero-foil blades 152. Due to the shape and angle of the aero-foil blades 152, the air flow is generated and directed into the rotor duct. The air flow circulates from outside of the rotor assembly 101 into the rotor duct, as also shown by arrows X in Figures 1A-1B. That is, the plurality of aero-foil blades 152 are configured to generate an airflow in a closed-loop within the rotor duct of the rotor assembly 101. The air flow creates turbulence in the rotor duct which increases the heat dissipation. Efficient heat dissipation is thus achieved in the motor assembly 100 during operation of the rotor assembly 101. Further, optimal performance and reliability is ensured by regulating the operating temperature.
[062] Rotor cooling Computational Fluid Dynamics (CFD) may be performed for validating the design and in order to understand the effect of the fan assembly 150 on the temperature and flow within the motor assembly 100. In CFD analysis, the magnet is demagnetized due to high-temperature generation in rotor assembly 101 and flow characteristic inside the motor assembly 100 is investigated.
[063] Figure 5A depicts temperature contouring on the air domain of a conventional motor assembly while Figure 5B depicts temperature contouring on the air domain of the motor assembly 100 integrated with the fan assembly 150. In Figures 5A-5B, a comparison of temperature differences between the air domain portions is depicted. Figures 6A-6B depict a comparison of temperature differences via heat maps associated with a conventional rotor assembly and heat map associated with the rotor assembly having integrated fan assembly. Figure 7 depicts the effect of the fan assembly 150 on the temperature and flow through Rotor cooling Computational Fluid Dynamics (CFD) analysis. The temperature effect or heat dissipation in the motors without fan assembly and with integrated fan assembly 150 can be observed. The motor assembly 100 with integrated fan assembly 150 as disclosed herein can be seen with temperature lowering (cooling effect) in Figure 6B.
[064] Table 1 below depicts the pre-processing material properties:

Component Material Data
Endplate Aluminum
Screws Carbon Steel
Magnet Neodymium
Rotor Core Electrical steel
Fluid Air Ideal Gas
Table 1 [065] Table 2 below depicts heat-loss data:

Component Heat Loss (in Watt)
Rotor 5
Magnet 101
Table 2
[066] Boundary Condition for the analysis: Rotor and Magnets are heat source components for thermal analysis. Air ambient temperature is taken as 27°C. Stat Air Walls are treated at constant wall temperature boundary conditions with a temperature of 120°C. Fan material is assumed to be homogeneous and isotropic. Heat transfer effects due to radiation are neglected. All contacts between components are ideal.
[067] Post-Processing observations are depicted in Table 3 below:

Components Rotor without Fan (C) Rotor with Fan (C) Temperature Difference % (C)
Rotor 186.79 180.49 3.5
Magnet 187.59 181.34 3.45
Screws 185.96 179.6 3.54
Rot Air 186.52 180.29 3.45
Stat Air 162.38 161.08 1
Endplate 184.64 177.8 3.85
Fan - 168.85 -

[068] Table 4 below depicts calculated values for motor assembly 100. Highlighted rows depict the inputs taken from the design of the aero-foil blades and angle of the aero¬foil blades are accordingly calculated.

Parameters Values Unit
Rotor speed 4200 Rpm
Plate ID 38 Mm
Plate ID 68 mm
Blade velocity u1 8.4 m/s
Blade velocity u2 14.9 m/s
Atmospheric pressure P1 101.3 kPa
Atmospheric temp. T1 300 K
Air flow rate 0.02 Kg/s
Air Density 1.18 Kg/m3
Rotor cavity area A1 0.002 M2
Intel air velocity in cavity 6.98 m/s
Angle 39.88 Deg.
Table 4
[069] Thus, the rotor components show 3.5% to ~ 4% drop in temperature with the fan assembly 150.
[070] The present invention thus discloses an integrated assembly having aero-foil design blades integrated with rotor end plate of the motor assembly. The integrated fan assembly is designed to enable circulation of airflow inside the rotor duct and create turbulence flow to effectively dissipate heat from the rotor assembly. The angles of the aero-foil blades collect static air from the rear end of the motor assembly and create a flow through the rotor duct to reduce the overall temperature of the assembly with reduced noise.
[071] The detailed description is merely exemplary in nature and is not intended to limit the described embodiments or the application and uses of the described embodiments. As used herein, the word “exemplary” or “illustrative” means “serving as an example, instance, or illustration.” Any implementation described herein as “exemplary” or
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“illustrative” is not necessarily to be construed as preferred or advantageous over other embodiments. All of the embodiments described below are exemplary embodiments provided to enable persons skilled in the art to make or use the embodiments of the disclosure and are not intended to limit the scope of the disclosure, which is defined by the claims. For purposes of description herein, the terms “upper”, “lower”, “left”, “rear”, “right”, “front”, “vertical”, “horizontal”, and derivatives thereof shall relate to the invention as oriented in the drawings. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, brief summary or the following detailed description. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification, are simply exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise.
[072] In the following description, certain specific details are set forth in order to provide a thorough understanding of various disclosed embodiments. However, one skilled in the relevant art will recognize that embodiments may be practiced without one or more of these specific details, or with other methods, components, materials, and the like. In other instances, well-known elements associated with motors have not been shown or described in detail to avoid unnecessarily obscuring descriptions of the embodiments.
[073] Since many modifications, variations, and changes in detail can be made to the described preferred embodiments of the invention, it is intended that all matters in the foregoing description and shown in the accompanying drawings be interpreted as illustrative and not in a limiting sense. Thus, the scope of the invention should be determined by the appended claims and their legal equivalents
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WE CLAIM:
1. A motor assembly comprising:
a stator assembly;
a rotor assembly magnetically coupled with the stator assembly, the rotor assembly comprising a rotor duct configured to allow flow of air there-between; and
a fan assembly coupled to the rotor assembly, the fan assembly comprising a rotor end plate and a plurality of aero-foil blades integrated with the rotor end plate at pre-defined angles,
wherein the plurality of aero-foil blades are configured to generate an airflow into the rotor duct based on the pre-defined angles upon rotation of the rotor assembly and the fan assembly, thereby enabling heat dissipation in the motor assembly during operation of the rotor assembly.
2. The motor assembly of claim 1, wherein the plurality of aero-foil blades are integrated with the rotor end plate at a predetermined distance with respect to each other.
3. The motor assembly of claim 1, wherein the fan assembly comprises a plurality of holes configured to receive corresponding nuts for fixedly coupling the fan assembly with the rotor assembly, wherein rotation of the rotor assembly causes simultaneous rotation of the fan assembly.
4. The motor assembly of claim 3, wherein each of the plurality of holes is alternatively positioned between a corresponding pair of aero-foil blades amongst the plurality of aero-foil blades.

5. The motor assembly of claim 1, wherein the plurality of aero-foil blades include a first type of blades and a second type of blades, and wherein the first type of blades have a chord line length smaller that a chord line length of the second type of blades.
6. The motor assembly of claim 5, wherein the first type of blades and the second type of blades are alternatively integrated on the rotor end plate.
7. The motor assembly of claim 1, wherein the plurality of aero-foil blades are configured to generate an airflow in a closed-loop within the rotor duct of the rotor assembly.
8. The motor assembly of claim 1, wherein each of the plurality of aero-foil blades has a blade thickness of 3.5mm, and wherein the rotor end plate has a thickness of 3mm.
Dated this 27th Day of March, 2024
Varroc Engineering Limited