DESC:WOUND CORE TOOTH FOR YOKELESS AXIAL FLUX MOTOR
CROSS REFERENCE TO RELATED APPLICTIONS
The present application claims priority from Indian Provisional Patent Application No. 202221041424 filed on 19/07/2022, the entirety of which is incorporated herein by a reference.
TECHNICAL FIELD
Generally, the present disclosure relates to a wound core tooth for electric motor. Particularly, the present disclosure relates to a wound core tooth for a yokeless axial flux motor. Furthermore, the present disclosure also relates to a stator assembly of a yokeless axial flux motor.
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 winded bobbin is mounted above the core. However, there exist a gap between the bobbin and the periphery of the core, which leads to flux leakage. The leakage of flux would result in reduced power density and efficiency of the motor.
Moreover, in the conventional yokeless axial flux motors, once the bobbin, core and winding are assembled, 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 wound core tooth for 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 wound core tooth for a yokeless axial flux motor.
Another object of the present disclosure is to provide stator assembly for a yokeless axial flux motor.
In accordance with an aspect of the present disclosure, there is provided a wound core tooth for a yokeless axial flux motor. The wound core tooth 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.
The present disclosure provides a wound core tooth for a yokeless axial flux motor. Advantageously, the present invention provides an easy to assemble and disassemble solution for stator assembly of the yokeless axial flux motor. Furthermore, the disclosed wound core tooth is advantageous in terms of reducing flux leakage resulting into higher power density and efficiency. Moreover, the disclosed wound core tooth is easier and cost effective to manufacture. Moreover, the disclosed wound core tooth 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 wound core tooth for a yokeless axial flux motor, in accordance with an embodiment of the present disclosure.
Figure 2 illustrates an exploded view of stator assembly for a yokeless axial flux motor, in accordance with an 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 wound core tooth 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). 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. The coil windings are typically placed in slots or grooves on the stator disk or stator sleeve. The 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 term “stator sleeve” refers to disk-shaped structure with slots to accommodate plurality of wound core teeth. The stator sleeve 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 terms “wound core tooth”, and “tooth” are used interchangeably and refers to a component of the stator that generates and shape the magnetic field and contributes to the motor’s performance. It is to be understood that multiple wound core tooth 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 “two-part metallic core”, “metallic core”, “core” and “metal core” are used interchangeably and refers to a central part of tooth structure that is made of magnetic material. The metal core serves as a path for the magnetic flux within the stator of the motor providing low reluctance path for the magnetic field generated by the stator windings, allowing efficient transfer of magnetic energy between the stator and rotor. It is to be understood that the design of the metal core, including its shape, size, and lamination arrangement, may be optimized to provide a balance between magnetic efficiency, mechanical strength, and minimizing losses. The metal core contributes to the overall performance, efficiency, and power density of the axial flux motor. Particularly, in the present invention, the metallic core is made up of two parts, namely first part and second part. The first part and the second part of the two-part metallic core are of uniquely designed to complement each other forming a solid core of the tooth.
As used herein, the terms “plurality of lamination sheets”, “lamination sheets”, “lamination”, and “laminated iron” are used interchangeably and refer to thin, flat sheets of magnetic material used for forming the iron core in motor. The lamination sheets minimize energy losses caused by eddy currents. The eddy currents can generate heat and dissipate energy, reducing the efficiency of the device.
As used herein, the terms “plurality of steps”, and “steps” are used interchangeably and refer to stepped tapering where each subsequent step is smaller/bigger than the previous step.
As used herein, the term “locking means” refers to a unique arrangement of complementing design components that keep the first part and the second of the two-part metallic core together in place to form the solid core of the tooth.
As used herein, the term “spool” refers to a hollow bobbin-like structure on which the winding of the wire is done to form a coil and the metallic core is inserted into the hollow portion of the spool to form the wound core tooth. The spool may be made up of a non-conductive material that provides electrical insulation and mechanical stability. The spool may be specifically design to hold the coil in place and maintain desired shape and configuration.
As used herein, the term “conductive wiring” refers to wire to be wounded around the spool to form the coil. The conductive wiring may be made of material such as copper that is suitable for such purpose.
Figure 1, in accordance with an embodiment describes an exploded view of a wound core tooth 100 for a yokeless axial flux motor. The wound core tooth 100 comprises a two-part metallic core 102, a spool 106, and a conducting wiring 108. The two-part metallic core 102 comprises a first part 102a and a second part 102b concealed together via a locking means 104. The spool 106 is configured to accommodate the first part 102a and the second part 102b of the two-part metallic core 102. The conducting wiring 108 is coiled around the spool 106.
The present disclosure provides a wound core tooth 100 for a yokeless axial flux motor. Advantageously, the present invention provides an easy to assemble and disassemble solution for stator assembly 200 of the yokeless axial flux motor. Furthermore, the disclosed wound core tooth 100 is advantageous in terms of reducing flux leakage resulting into higher power density and efficiency. Beneficially, the wound core tooth 100 maintains the direction of the flux in desired position to enable the motor to run at highest efficiency. Moreover, the disclosed wound core tooth 100 is easy and cost effective to manufacture. Moreover, the disclosed wound core tooth 100 enables efficient utilization of the space inside the motor casing resulting in compact size of the motor.
In an embodiment, wherein the first part 102a and the second part 102b comprise a top surface 110, a bottom surface 112, an inner surface 114 and an outer surface 116. The first part 102a and the second part 102b are inserted into the spool 106 from mutually opposite direction to assemble the wound core tooth 100. Such insertion of the two-part metallic core 102 into the spool 106 results into top surface 110 and the bottom surface 112 of the first part 102a and the second part 102b being inside into the spool 106. Furthermore, the inner surface 114 of the first part 102a and the second part 102b comes in contact with each other once the wound core tooth 100 is assembled.
In an embodiment, the first part 102a and the second part 102b are tapered in plurality of steps, and wherein each subsequent step is smaller in width compared to previous step towards the top surface 110. Beneficially, the plurality of steps increases the ease of manufacturing of the wound core tooth 100 as it reduces the number of die required to cast the iron lamination layers. It is to be understood that number of die required would be equal to the number of steps in the first part 102a and the second part 102b.
In an embodiment, the locking means 104 comprises at least one locking groove 104a located on the inner surface 114 of the first part 102a, and at least one locking protrusion 104b located on the inner surface 114 of the second part 102b. Specifically, in an embodiment, the at least one locking groove 104a and the at least one locking protrusion 104b are aligned with each other such that the at least one locking groove 104a of the first part 102a receives the at least one locking protrusion 104b of the second part 102b to conceal together the two-part metallic core 102 inside the spool 106. It is to be understood that to assemble the two-part metallic core 102, the first part 102a and the second part 102b are inserted into the spool 106 from mutually opposite direction until the at least one locking protrusion 104b is received by the at least one locking groove 104a and the inner surface 114 of the first part 102a and the second part 102b comes in physical contact with each other. In an embodiment, the at least one locking protrusion 104b snugly fits and locks into the at least one locking groove 104a. Beneficially, such unique design and assembly process enable the two-part metallic core 102 to comprise means for reducing flux leakage. Thus, such unique design and assembly enable higher efficiency of the motor by reducing air gap in the construction of the wound core tooth 100.
In an embodiment, the outer surface 116 of the first part 102a and the second part 102b comprises outer surface extensions 118 extended along the plurality of steps. Beneficially, the outer surface extension 118 is stepped similarly to the plurality of steps creating a boundary to prevent flux leakage. Due to the outer surface extensions 118, core of the wound core tooth 100 is designed as a two-part metallic core 102. The two-part configuration enables the assembly of the wound core tooth 100 with outer surface extension 118 on the outer surface 116.
In an embodiment, the outer surface extensions 118 reduce an air-gap between the spool 106 and the two-part metallic core 102 to prevent flux leakage. Beneficially, the outer surface extensions 118 covers edges of the spool 106 on which the conducting wiring 108 is wound around to form the electromagnetic coil. Such covering of edges beneficially guides the flux in desired direction and prevents any leakage through the air as the air-gap is reduced.
In an embodiment, the first part 102a and the second part 102b are formed by stacking a plurality of lamination, and wherein the plurality of lamination are sized according to the plurality of steps. It is to be understood that the formation of the first part 102a and the second part 102b is done by stacking a plurality of lamination onto each other. Specifically, in an embodiment, the plurality of lamination are grouped into sizes according to the steps in the plurality of steps. In an example if the two-part metallic core 102 is required to be 5 cms in height with 5 tapering steps, 5 size groups of lamination sheets may be created for stacking together to form the first part 102a and the second part 102b of the two-part core 102. Furthermore, if thickness of one lamination is 0.5 mm, then 20 laminations of same size would be required to form first size step from the plurality of steps of the first part 102a and the second part 102b. Similarly, 20 laminations sized according to the subsequent larger step are stacked on the previous stack to form the subsequent step from the plurality of steps of the first part 102a and the second part 102b. The above process may be repeated until the desired height of the first part 102a and the second part 102b is achieved to form the two-part metallic core. Beneficially, the sizing of the lamination according to the plurality of steps reduces the manufacturing complexity as the required number of die are reduced from requiring uniquely sized die for each lamination for providing uniform tapering to requiring die sized according to the number of steps in the plurality of steps.
Figure 2, in accordance with an embodiment describes an exploded view of stator assembly 200 for a yokeless axial flux motor comprising a plurality of wound core teeth 100. In an embodiment, the plurality of wound core teeth 100 are arranged in a stator sleeve 202 to form the stator assembly 200. It may be appreciated that the wound core tooth 100 snugly fits into the stator sleeve 202 and the stator sleeve 202 provides mechanical support to the plurality of teeth 100 during the operation of the motor.
It would be appreciated that all the explanations and embodiments of the wound core tooth 100 also applies mutatis-mutandis to the stator assembly 200.
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 wound core tooth (100) for a yokeless axial flux motor comprising:
- a two-part metallic core (102) comprising a first part (102a) and a second part (102b) concealed together via a locking means (104);
- a spool (106) configured to accommodate the first part (102a) and the second part (102b) of the two-part metallic core (102); and
- a conducting wiring (108) coiled around the spool (106).
2. The wound core tooth (100) as claimed in claim 1, wherein the first part (102a) and the second part (102b) comprise a top surface (110), a bottom surface (112), an inner surface (114) and an outer surface (116).
3. The wound core tooth (100) as claimed in claim 1 and 2, wherein the first part (102a) and the second part (102b) are tapered in plurality of steps, and wherein each subsequent step is smaller in width compared to previous step towards the top surface (110).
4. The wound core tooth (100) as claimed in claim 1, wherein the locking means (104) comprises at least one locking groove (104a) located on the inner surface (114) of the first part (102a), and at least one locking protrusion (104b) located on the inner surface (114) of the second part (102b).
5. The wound core tooth (100) as claimed in claim 1 and 4, wherein the at least one locking groove (104a) and the at least one locking protrusion (104b) are aligned with each other such that the at least one locking groove (104a) of the first part (102a) receives the at least one locking protrusion (104b) of the second part (102b) to conceal together the two-part metallic core (102) inside the spool (106).
6. The wound core tooth (100) as claimed in claim 1 to 5, wherein the outer surface (116) of the first part (102a) and the second part (102b) comprises outer surface extensions (118) extended along the plurality of steps.
7. The wound core tooth (100) as claimed in claim 1 to 6, wherein the outer surface extensions (118) reduce an air-gap between the spool (106) and the two-part metallic core (102) to prevent flux leakage.
8. The wound core tooth (100) as claimed in claim 1 to 7, wherein the first part (102a) and the second part (102b) are formed by stacking a plurality of lamination, and wherein the plurality of lamination are sized according to the plurality of steps.
9. A stator assembly (200) for a yokeless axial flux motor, comprising a plurality of wound core teeth (100) as claimed in claim 1.
10. The stator assembly (200) as claimed in claim 9, wherein the plurality of wound core teeth (100) are arranged in a stator sleeve (202) to form the stator assembly (200).