DESC:CASE MOUNTED STATOR ASSEMBLY FOR YOKELESS MOTOR
CROSS REFERENCE TO RELATED APPLICTIONS
The present application claims priority from Indian Provisional Patent Application No. 202221041423 filed on 19/07/2022, the entirety of which is incorporated herein by a reference.
TECHNICAL FIELD
Generally, the present disclosure relates to a yokeless axial flux motor. Particularly, the present disclosure relates to a yokeless axial flux motor with stator assembly directly mounted in motor casing.
BACKGROUND
Recently, electric vehicles have emerged as an alternative to the conventional vehicles using gasoline and diesel and similar fossil fuels. The electric vehicles require traction motors to convert the electrical energy into mechanical energy for driving the vehicle. There are multiple types of electric motor being used in electric vehicles. Some known types of electrical motor are radial flux motors and axial flux motor. The radial flux motors are more commonly used as they are known for a longer time, however, radial flux motors have limitations such as longer axial length, low power and torque density, higher losses and weight.
The axial flux motors overcome these limitations, because, in the axial flux motor, the direction of the lines of magnetic flux that are cut during the operation of the motor is parallel to the rotational axis of the motor. The axial flux motors have characteristics including small axial length, higher power and torque density, lesser losses and lesser weight compared to radial flux motors. Furthermore, the yokeless axial flux motors are even more suitable for use as traction motors due to the absence of traditional yoke structure. The yokeless axial flux motor has efficient magnetic circuit resulting in reduced losses.
The yokeless axial flux motor comprises a stator having a plurality of wound core teeth or stator assemblies arranged circumferentially. The wound core tooth comprises a bobbin, a core and conductors wound over the bobbin. The wound core tooth is mounted on a stator sleeve. However, such mounting is inefficient due to the presence of non-flux weight of the stator sleeve. The additional weight would reduce the efficiency of the motor and requires more space.
Moreover, in the conventional yokeless axial flux motors, once the bobbin, core and winding are assembled into the stator sleeve, the process of disassembling the structure is highly tedious leading to greater complexity in motor servicing and maintenance.
Therefore, there exists a need for an improved yokeless axial flux motor that overcomes the one or more problems associated with the conventional yokeless axial flux motor assemblies as set forth above.
SUMMARY
An object of the present disclosure is to provide a yokeless axial flux motor with stator assembly directly mounted in motor casing.
In accordance with an aspect of the present disclosure, there is provided a yokeless axial flux motor comprising a stator assembly, at least one rotor assembly coaxial to the stator assembly, a motor shaft connected with the at least one rotor assembly, and a motor casing. The stator assembly comprises a plurality of wound core teeth. The motor casing is configured to accommodate the stator assembly, the at least one rotor assembly and the motor shaft, characterized in that the stator assembly is directly mounted in the motor casing.
The present disclosure provides a yokeless axial flux motor with improved efficiency and power density. Advantageously, the yokeless axial flux motor as disclosed, eliminates the requirement of stator sleeve for assembling the stator assembly. Furthermore, the yokeless axial flux motor as disclosed, has lesser weight compared to any conventional yokeless axial flux motor. Furthermore, the present invention provides an easy to assemble and disassemble solution for stator assembly of the yokeless axial flux motor. Furthermore, the disclosed yokeless axial flux motor is advantageous in terms of providing higher power density and efficiency. Furthermore, the disclosed yokeless axial flux motor is easier and cost effective to manufacture. Moreover, the disclosed yokeless axial flux motor enables efficient utilization of the space inside the motor casing resulting in compact size of the motor.
Additional aspects, advantages, features and objects of the present disclosure would be made apparent from the drawings and the detailed description of the illustrative embodiments constructed in conjunction with the appended claims that follow.
It will be appreciated that features of the present disclosure are susceptible to being combined in various combinations without departing from the scope of the present disclosure as defined by the appended claims.
BRIEF DESCRIPTION OF DRAWINGS
The summary above, as well as the following detailed description of illustrative embodiments, is better understood when read in conjunction with the appended drawings. For the purpose of illustrating the present disclosure, exemplary constructions of the disclosure are shown in the drawings. However, the present disclosure is not limited to specific methods and instrumentalities disclosed herein. Moreover, those in the art will understand that the drawings are not to scale. Wherever possible, like elements have been indicated by identical numbers.
Embodiments of the present disclosure will now be described, by way of example only, with reference to the following diagrams wherein:
Figure 1 illustrates an exploded view of a yokeless axial flux motor, in accordance with an embodiment of the present disclosure.
Figure 2 illustrates an exploded view of a yokeless axial flux motor, in accordance with another embodiment of the present disclosure.
In the accompanying drawings, an underlined number is employed to represent an item over which the underlined number is positioned or an item to which the underlined number is adjacent. A non-underlined number relates to an item identified by a line linking the non-underlined number to the item. When a number is non-underlined and accompanied by an associated arrow, the non-underlined number is used to identify a general item at which the arrow is pointing.
DETAILED DESCRIPTION
The following detailed description illustrates embodiments of the present disclosure and ways in which they can be implemented. Although some modes of carrying out the present disclosure have been disclosed, those skilled in the art would recognise that other embodiments for carrying out or practising the present disclosure are also possible.
The description set forth below in connection with the appended drawings is intended as a description of certain embodiments of a yokeless axial flux motor and is not intended to represent the only forms that may be developed or utilised. The description sets forth the various structures and/or functions in connection with the illustrated embodiments; however, it is to be understood that the disclosed embodiments are merely exemplary of the disclosure that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimised to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention.
While the disclosure is susceptible to various modifications and alternative forms, specific embodiment thereof has been shown by way of example in the drawings and will be described in detail below. It should be understood, however, that it is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternatives falling within the scope of the disclosure.
The terms “comprise”, “comprises”, “comprising”, “include(s)”, or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a setup, system that comprises a list of components or steps does not include only those components or steps but may include other components or steps not expressly listed or inherent to such setup or system. In other words, one or more elements in a system or apparatus preceded by “comprises... a” does not, without more constraints, preclude the existence of other elements or additional elements in the system or apparatus.
In the following detailed description of the embodiments of the disclosure, reference is made to the accompanying drawings and which are shown by way of illustration specific embodiments in which the disclosure may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the disclosure, and it is to be understood that other embodiments may be utilized and that changes may be made without departing from the scope of the present disclosure. The following description is, therefore, not to be taken in a limiting sense.
The present disclosure will be described herein below with reference to the accompanying drawings. In the following description, well known functions or constructions are not described in detail since they would obscure the description with unnecessary detail.
As used herein, the terms “electric motor”, “motor”, “yokeless motor”, “yokeless axial flux motor” and “axial flux motor” are used interchangeably and refer to electric motors capable of being implemented in an industrial or automobile application, such as on the work machine or other vehicle. The yokeless axial flux motor is a specific type of electric motor that utilizes an axial flux configuration and lacks a yoke in its design. The yokeless axial flux motors are advantageous in terms of providing high power density and efficiency. In a yokeless axial flux motor, the magnetic flux lines run parallel to the axis of rotation. The yokeless axial flux motor referred herein is a type of permanent magnet synchronous reluctance motor that combines the features of Permanent Magnet Synchronous Motor (PMSM) and Reluctance Motor (RM) known as Permanent Magnet Synchronous Reluctance Motor (PMSRM). The PMSRM has permanent magnets in the rotor, which generates a constant magnetic field, and the PMSRM relies on the principle of magnetic reluctance to create a rotating field within the motor. It would be appreciated that combination of technologies allows the PMSRM to achieve higher efficiency and better performance than other types of electric motors.
As used herein, the terms ‘electric vehicle’, ‘EV’, and ‘EVs’ are used interchangeably and refer to any vehicle having stored electrical energy, including the vehicle capable of being charged from an external electrical power source. This may include vehicles having batteries which are exclusively charged from an external power source, as well as hybrid-vehicles which may include batteries capable of being at least partially recharged via an external power source. Additionally, it is to be understood that the ‘electric vehicle’ as used herein includes electric two-wheeler, electric three-wheeler, electric four-wheeler, electric pickup trucks, electric trucks and so forth.
As used herein, the terms ‘stator’ and ‘stator assembly’ are used interchangeably and refer to the stationary part of a motor which provides a magnetic field that drives the rotating armature. The stator may act as a field magnet. The stator of the yokeless axial flux motor typically consists of a disk-shaped structure with coil windings. Specifically, the coil windings are directly placed in slots or grooves on the motor casing eliminating a stator sleeve. The coil windings, also called stator windings, are responsible for generating a magnetic field when electric current passes through them. The magnetic field produced by the stator interacts with the permanent magnets on the rotor to induce rotation.
As used herein, the terms “plurality of wound core teeth”, “wound core teeth” and “teeth” are used interchangeably and refers to a component of the stator assembly that generates and shape the magnetic field and contributes to the motor’s performance. It is to be understood that multiple wound core teeth are arranged in a disc plane to form a segmented stator assembly. The wound core tooth is typically made of laminated iron or other magnetic materials suitable for high efficiency operation of the motor. The design and configuration of the wound core teeth, along with the stator windings, play a crucial role in the performance and efficiency of a yokeless axial flux motor. They contribute to the motor's ability to generate torque, provide smooth and reliable operation, and optimize power density.
As used herein, the terms ‘rotor’ and ‘rotor assembly’ are used interchangeably and refer to the rotating part of the motor which is typically made of iron or other magnetic materials. It contains the permanent magnets and the reluctance winding that generate the magnetic field used to drive the rotor. The rotor converts electrical energy supplied to the stator into mechanical energy.
As used herein, the term “motor shaft”, “shaft” and “shaft assembly” are used interchangeably and refer to a cylindrical rotating component of the motor for delivering mechanical output to a load.
As used herein, the term “motor casing” is used to refer to the outer body of a motor enclosure, which holds the entire motor. The motor casing is typically made of a durable and rigid material, such as metal or high-impact plastic, that can withstand the mechanical stresses and environmental conditions associated with motor operation.
As used herein, the term “front-end case” refers to the front-end of the metal motor casing structure. The front-end case is metal motor casing structure fixed at the frontal end or proximal end of the electric motor where a mechanical load is connected to the motor shaft of the electric motor.
As used herein, the term “rear-end cover” refers to metal motor casing structure fixed at the rear end or distal end of the electric motor with reference to the connection of the load to the motor shaft of the electric motor.
As used herein, the terms “plurality of slots” and “slots” are used interchangeably and refers to a designated space in the cylindrical wall of the motor casing configured to receive the plurality of wound core teeth.
As used herein, the term “locking mechanism” refers to structure with a central ring and plurality of fins radiating from the central ring forming space for accommodating one wound core teeth between two adjacent fins wherein the ring supports the axial side of the wound core teeth. The locking mechanism is designed to hold the plurality of wound core teeth in place during the operation of the yokeless axial flux motor.
As used herein, the term “directly-mounted” refers to design configuration in which the wound core teeth of the stator assembly are attached or fixed directly onto the inner surface of the motor casing, without the use of a separate stator sleeve.
Figure 1, in accordance with an embodiment describes an exploded view of a yokeless axial flux motor 100 comprising a stator assembly 102, at least one rotor assembly 106, a motor shaft 108 and a motor casing 110. The stator assembly 102 comprises a plurality of wound core teeth 104. The at least one rotor assembly 106 is coaxial to the stator assembly 102. The motor shaft 108 is connected with the at least one rotor assembly 106. The motor casing 110 is configured to accommodate the stator assembly 102, the at least one rotor assembly 106 and the motor shaft 108, characterized in that the stator assembly 102 is directly mounted in the motor casing 110.
The present disclosure provides a yokeless axial flux motor 100 with improved efficiency and power density. Advantageously, the present invention provides an easy to assemble and disassemble solution for stator assembly 102 of the yokeless axial flux motor 100. Furthermore, the yokeless axial flux motor 100 as disclosed, eliminates the requirement of stator sleeve for assembling the stator assembly 102. It would be appreciated that the plurality of would core teeth 104 are directly mounted in the motor casing 100 without first mounting into any stator sleeve. Such direct mounting of the plurality of would core teeth 104 in the motor casing 110 would be beneficially having lesser weight compared to any conventional yokeless axial flux motor. Furthermore, the yokeless axial flux motor 100 has lower non-flux weight i.e., low weight of components which are not generating any flux, resulting into increased power density and efficiency. Furthermore, the yokeless axial flux motor 100 is easier to manufacture and assemble due to reduced components. Advantageously, the yokeless axial flux motor 100 is cost efficient in manufacturing, servicing and maintenance. Moreover, the yokeless axial flux motor 100 enables efficient utilization of the space inside the motor casing 110 resulting in compact size of the motor 100. Advantageously, the yokeless axial flux motor 100 is suitable for sophisticated application such as use in powertrain of an electric vehicle.
In an embodiment, the at least one rotor assembly 106 comprises two rotor assemblies, wherein the rotor assemblies are mounted coaxially towards either side of the stator assembly 102. Beneficially, the dual rotor or twin rotor configuration increases the torque generation capacity of the yokeless axial flux motor 100.
Figure 2, in accordance with an embodiment describes an exploded view of a yokeless axial flux motor 100 comprising a stator assembly 102, a rotor assembly 106, a motor shaft 108 and a motor casing 110. The stator assembly 102 comprises a plurality of wound core teeth 104. The at least one rotor assembly 106 is coaxial to the stator assembly 102. The motor shaft 108 is connected with the at least one rotor assembly 106. The motor casing 110 is configured to accommodate the stator assembly 102, the at least one rotor assembly 106 and the motor shaft 108, characterized in that the stator assembly 102 is directly mounted in the motor casing 110.
In an embodiment, the plurality of wound core teeth 104 comprises a two-part metallic core comprising a first part and a second part concealed together via a locking means, a spool configured to accommodate the first part and the second part of the two-part metallic core, and a conducting wiring coiled around the spool. Beneficially, the wound core tooth 104 is advantageous in terms of reducing flux leakage resulting into higher power density and efficiency of the yokeless axial flux motor 100. It is to be understood that first part and the second part are inserted into the spool from mutually opposite direction to assemble the wound core teeth 104.
In an embodiment, the motor casing 110 comprises a front-end case 110a and a rear-end cover 110b. Specifically, in an embodiment, the front-end case 110a accommodates at least one of: the stator assembly 102, the at least one rotor assembly 106 and the motor shaft 108.
In an embodiment, the rear-end cover 110b accommodates at least one of: a position sensor and electronic control unit. Beneficially, the accommodation of at least one of: the position sensor and the electronic control unit in the rear-end cover 110b further improves the utilization of space inside the yokeless axial flux motor 100 resulting in a more compact design.
In another embodiment, at least one of: the position sensor and the electronic control unit are mounted in front of the front-end case 110a. In such embodiment, the rear-end cover 110b accommodates components of a cooling system configured for the cooling of the yokeless axial flux motor 100. Beneficially, the accommodation of the components of the cooling system enables effective utilization of space inside the yokeless axial flux motor 100 resulting in a more compact design.
In yet another embodiment, the rear-end cover 110b accommodates the position sensor the electronic control unit and the components of the cooling system. Beneficially, the accommodation of the position sensor the electronic control unit and the components of the cooling system in the rear-end cover 110b enables most compact design of the yokeless axial flux motor 100.
In an embodiment, the front-end case 110a comprises a base plate and a cylindrical wall around the periphery of the base plate. Beneficially, the base plate mechanically supports components of the yokeless axial flux motor 100 in axial direction. Similarly, the cylindrical wall around the periphery of the base plate mechanically supports components of the yokeless axial flux motor 100 in radial direction and receives the plurality of the wound core teeth 104.
In an embodiment, the cylindrical wall comprises a plurality of slots 112 for mounting of the plurality of wound core teeth 104 of the stator assembly 102. Beneficially, the plurality of wound core teeth 104 are directly mounted into the plurality of slots 112 eliminating any requirement of stator sleeve resulting into easier assembling and disassembling process of the stator assembly 102 in the yokeless axial flux motor 100. Moreover, the cylindrical wall prevents any outward radial movement of the plurality of wound core teeth 104 during the operation of the yokeless axial flux motor 100.
In an embodiment, the stator assembly 102 comprises a locking mechanism 114 for securing the plurality of wound core teeth 104 in the plurality of slots 112. Beneficially, the locking mechanism 114 secures the plurality of wound core teeth 104 in place and prevent any movement of the plurality of wound core teeth 104 during operation of the yokeless axial flux motor 100. The locking mechanism 114 functions to maintain the structural integrity and performance of the yokeless axial flux motor 100.
In an embodiment, the locking mechanism 114 comprises a locking ring 114a co-axial to the motor shaft 108 and a plurality of fins 114b extending radially from circumference of the locking ring 114a to the cylindrical wall. Beneficially, the locking ring 114a prevents any inward radial movement of the plurality of wound core teeth 104 during the operation of the yokeless axial flux motor 100. Beneficially, the plurality of fins 114b are configured to tightly fit the plurality of wound core teeth 104 between the plurality of fins 114b restricting any angular movement of the plurality of wound core teeth 104 during the operation of the yokeless axial flux motor 100.
In an embodiment, the cylindrical wall comprises a plurality of grooves 116 to receive and secure radial end of the plurality of fins 114b. It is to be understood that the radial end of each fin of the plurality of fins 114b fits into respective groove of the plurality of grooves 116 restricting any angular movement of the locking mechanism 114 during the operation of the yokeless axial flux motor 100.
Beneficially, it is to be understood that arrangement of the cylindrical wall, the base plate, the locking ring 114a and the plurality of fins 114b securely holds the plurality of wound core teeth 104 and prevents any movement of the same during the operation of the yokeless axial flux motor 100.
In an embodiment, the plurality of slots 112 and the locking mechanism 114 comprises at least one cooling channel for cooling the stator assembly 102. Beneficially, the at least one cooling channel of the plurality of slots 112 and the locking mechanism 114 is connected to the cooling system. The cooling system enables a coolant to flow through the at least one cooling channel exchanging the heat from the stator assembly 102 leading to cooling of the stator assembly 102.
In the description of the present invention, it is also to be noted that, unless otherwise explicitly specified or limited, the terms “disposed,” “mounted,” and “connected” are to be construed broadly, and may for example be fixedly connected, detachably connected, or integrally connected, either mechanically or electrically. They may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.
Modifications to embodiments and combination of different embodiments of the present disclosure described in the foregoing are possible without departing from the scope of the present disclosure as defined by the accompanying claims. Expressions such as “including”, “comprising”, “incorporating”, “have”, “is” used to describe and claim the present disclosure are intended to be construed in a non- exclusive manner, namely allowing for items, components or elements not explicitly described also to be present. Reference to the singular is also to be construed to relate to the plural where appropriate.
Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the present disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.

,CLAIMS:WE CLAIM:
1. A yokeless axial flux motor (100) comprising:
- a stator assembly (102) comprising a plurality of wound core teeth (104);
- at least one rotor assembly (106) coaxial to the stator assembly (102);
- a motor shaft (108) connected with the at least one rotor assembly (106); and
- a motor casing (110) configured to accommodate the stator assembly (102), the at least one rotor assembly (106) and the motor shaft (108),
characterized in that the stator assembly (102) is directly mounted in the motor casing (110).
2. The yokeless axial flux motor (100) as claimed in claim 1, wherein the motor casing (110) comprises a front-end case (110a) and a rear-end cover (110b).
3. The yokeless axial flux motor (100) as claimed in claim 1 and 2, wherein the front-end case (110a) accommodates at least one of: the stator assembly (102), the at least one rotor assembly (106) and the motor shaft (108).
4. The yokeless axial flux motor (100) as claimed in claim 1 and 2, wherein the rear-end cover (110b) accommodates at least one of: a position sensor and electronic control unit.
5. The yokeless axial flux motor (100) as claimed in claim 1, 2 and 3, wherein the front-end case (110a) comprises a base plate and a cylindrical wall around the periphery of the base plate.
6. The yokeless axial flux motor (100) as claimed in claim 1 to 5, wherein the cylindrical wall comprises a plurality of slots (112) for mounting of the plurality of wound core teeth (104) of the stator assembly (102).
7. The yokeless axial flux motor (100) as claimed in claim 1 to 6, wherein the stator assembly (102) comprises a locking mechanism (114) for securing the plurality of wound core teeth (104) in the plurality of slots (112).
8. The yokeless axial flux motor (100) as claimed in claim 1 to 7, wherein the locking mechanism (114) comprises a locking ring (114a) co-axial to the motor shaft (108) and a plurality of fins (114b) extending radially from circumference of the locking ring (114a) to the cylindrical wall.
9. The yokeless axial flux motor (100) as claimed in claim 1 to 8, wherein the cylindrical wall comprises a plurality of grooves (116) to receive and secure radial end of the plurality of fins (114b).
10. The yokeless axial flux motor (100) as claimed in claim 1 to 9, wherein the plurality of slots (112) and the locking mechanism (114) comprises at least one cooling channel for cooling the stator assembly (102).