Description:TECHNICAL FIELD
[0001] The present disclosure relates to the field of field of axial flux motors. In particular, the present disclosure pertains to a laminated stator assembly for a dual-rotor axial flux motor, and method for manufacturing the same.

BACKGROUND
[0002] A motor is a device that converts electrical energy into mechanical energy. Motors are categorized into two types based on the orientation of the magnetic field: radial flux motors and axial flux motors. An axial flux motor features a unique design where the magnetic flux aligns parallel to the motor's shaft. This configuration enables the creation of compact, lightweight motors with high torque, making them suitable for various applications such as electric vehicles and renewable energy systems. Axial flux motors are recognized for their efficiency and versatility in confined spaces. In contrast, in a radial flux motor, the magnetic flux runs perpendicular to the axis of rotation, while in an axial flux motor, the axis of rotation aligns parallel to the flux lines.
[0003] An axial flux motor, sometimes called an axial gap motor or pancake motor, diverges from the standard radial flux motor layout by aligning a gap between the rotor and stator, along with the magnetic flux direction, parallel to the motor's axis of rotation, as opposed to the usual radial alignment within concentric cylinders.
[0004] Axial flux motors typically employ a stator assembly constructed from numerous layers of ferromagnetic material plates arranged to create the stator assembly. The fabrication of such stators is notably intricate. Typically, the stator in these motors consists of multiple trapezoidal-shaped segments, each segment being a composition of hundreds of plates, each with varying widths. These stator segments are tailored to fit into specific sections of the motor, encircled by copper wires that supply electrical current to them. The plates are commonly crafted from lamination steel, chosen for its magnetic properties despite presenting significant production challenges. These challenges primarily stem from the diverse widths, sizes, and brittleness of the plates, rendering traditional cutting or stamping processes inefficient. An alternative material under consideration is soft magnetic composite. While this material could streamline the manufacturing process, it tends to result in higher core losses during operation due to its relatively lower magnetic permeability compared to lamination steel.
[0005] The current techniques that are available to produce such stators for a dual-rotor axial flux motor include a continuous stamping process, which is also employed for radial flux motors, involves stamping a long and continuous sheet of material 102, as shown in FIG. 1, as it rolls to produce a single stator unit 100 with predefined internals. However, the continuous stamping process is not suitable for producing stators for dual-rotor axial flux motors because each stator segment 104 produced by such continuous stamping process is interconnected at the rear 106, which prevents the magnetic flux from exiting such stators segments 104. Instead, the continuous stamping process provides a continuous pathway 108 for the flux to pass through another stator segment 104, as shown in FIG. 1. A single stator for a dual-rotor axial flux motor would need to be disconnected from an adjacent segment, and requires top and bottom pole shoes that help magnetic flux to spread out for better uniformity, and reduce reluctance of the magnetic path, which is not possible to be produced by the continuous stamping process.
[0006] Another technique 200, as depicted in FIG. 2, currently employed for manufacturing stators involves manually assembling numerous stamped stator pieces 202, which is time-consuming and typically necessitates additional laser welding sides 204 of the stator pieces to secure the stator assembly. However, the laser welding is known to compromise electrical insulation between each laminated status pieces 202 and introduces eddy current losses. In addition, the conventional technique 200 is extremely slow and introduces a laser weld prone to destroy the electrical insulation between the stator pieces 202.
[0007] Another method, as outlined in patent document US 2022/0200417 A1, involves bending a long strip of stator material at necessary points to form a stator stamping. While this process is simpler, it does not permit the incorporation of top and bottom pole shoes due to brittleness of the stator material, especially at the bend portions. It is commonly known that the stamping process naturally creates sharp edges that could come into contact with other plates, potentially compromising electrical insulation and necessitating additional insulation procedures.
[0008] Hence, there exists a necessity within the field to address the drawbacks and limitations inherent in current solutions. This entails delivering a straightforward, reliable, and economical laminated stator assembly for a dual-rotor axial flux motor, and a method for manufacturing the same. Moreover, such a laminated stator assembly and the method for producing the same should enhance the construction and quality of the stator assembly, while eliminating the need for wrapping multiple stator pieces with an insulation paper before winding them with copper wires.

OBJECTS OF THE PRESENT DISCLOSURE
[0009] An object of the present disclosure is to provide a simple and reliable laminated stator assembly for a dual-rotor axial flux motor, and a method for manufacturing the same.
[0010] Another object of the present disclosure is to provide a cost-efficient laminated stator assembly for a dual-rotor axial flux motor having improved construction and quality, and eliminates the requirement for wrapping multiple stator pieces with an insulation paper before winding them with copper wires, and a method for producing the same.
[0011] Another object of the present disclosure is to provide a reliable method for producing a laminated stator assembly for a dual-rotor axial flux motor that employs simple manufacturing automation components and makes stampings of the stator pieces in an efficient and compact manner.

SUMMARY
[0012] Aspects of the present disclosure relates to a laminated stator assembly for a dual-rotor axial flux motor, and a method for manufacturing the same. In an aspect, the laminated stator assembly includes a plurality of stator segments, each stator segment having a plurality of stator plates stacked one over another, at least one top pole shoe and at least one bottom pole shoe, and an insulation layer formed on at least one side surface of each of the plurality of stator plates after said plurality of stator plates are staked together.
[0013] In an embodiment, the insulation layer may include any of an adhesive and a resin adapted to couple at least one side surface of each of the plurality of stator plates.
[0014] In an embodiment, the at least one top pole shoe may be positioned at a top end of the plurality of stator plates stacked together. The at least one bottom pole shoe may be positioned at a bottom end of the plurality of stator plates stacked together.
[0015] In an embodiment, the plurality of stator plates may be stacked together to form the stator segment by any of laser cutting, plasma cutting, stamping and punching processes.
[0016] Another aspect of the present disclosure relates to a method for manufacturing a laminated stator assembly for a dual-rotor axial flux motor. The method includes coating at least one side surface of each stacking location of a plurality of stacking locations with an insulation layer, sequentially picking and dropping at least one stator plate of a plurality of stator plates at the stacking location, and stacking the at least one stator plate dropped at the stacking location to form a stator segment of the stator assembly.
[0017] In an embodiment, each stacking location of the plurality of stacking locations may be formed between two stator holders. In an embodiment, the stator holders may be arranged along a linear path. In another embodiment, the stator holders may be arranged along periphery of a circular stator holder. The coating may include applying the insulation layer to at least one side surface of each of the stator holders.
[0018] In an embodiment, the sequentially picking and dropping of the at least one stator plate may be performed by a robotic arm comprising a suction head to hold the at least one stator plate and drop the at least one stator plate at the stacking location.
[0019] In an embodiment, the stacking may include joining, by a plurality of tool holders, the plurality of stator plates together to form the stator segment by any of laser cutting, plasma cutting, stamping and punching processes. Each of the plurality of tool holders may face each stacking location of the plurality of stacking locations. The stacking may also include pulling each of the plurality of tool holders away from the stacking location after stacking of the at least one stator plate is complete, and curing the insulation layer after the plurality of stator plates are stacked together to form the stator segment.
[0020] In an embodiment, the present disclosure provides a simple, reliable and cost-efficient laminated stator assembly for a dual-rotor axial flux motor, and a method for manufacturing the same. The laminated stator assembly produced by the method has improved construction and quality, and the method eliminates the requirement to wrap multiple stator segments with insulation paper before winding them with copper wires. The method utilizes simple manufacturing automation components and facilitates stamping of the stator segments in an efficient and space-saving manner.
[0021] Various objects, features, aspects and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.

BRIEF DESCRIPTION OF THE DRAWINGS
[0022] The accompanying drawings are included to provide a further understanding of the present disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.
[0023] FIGs. 1 and 2 illustrate schematic representations of conventional techniques for forming a laminated stator for a motor in accordance with prior art;
[0024] FIG. 3A illustrates a perspective view of a stator segment of a laminated stator assembly for a dual-rotor axial flux motor in accordance with an embodiment of the present disclosure;
[0025] FIG. 3B shows a stator segment provided with copper wire winding and top and bottom extensions, in accordance with an embodiment of the present disclosure;
[0026] FIG. 4A illustrates an exemplary representation of a first configuration of an apparatus for manufacturing the stator segments of the laminated stator assembly, in accordance with an embodiment of the present disclosure;
[0027] FIG. 4B illustrates an exemplary representation of a second configuration of the apparatus for manufacturing the stator segments of the laminated stator assembly, in accordance with an embodiment of the present disclosure; and
[0028] FIG. 5 illustrates a flow chart depicting various processes of a method for manufacturing a laminated stator assembly for a dual-rotor axial flux motor, in accordance with an embodiment of the present disclosure;

DETAILED DESCRIPTION
[0029] The following is a detailed description of embodiments of the disclosure depicted in the accompanying drawings. The embodiments are in such details as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the present disclosures as defined by the appended claims.
[0030] Embodiments explained herein relate to a straightforward, reliable, and economically viable laminated stator assembly for a dual-rotor axial flux motor, along with a manufacturing method. The laminated stator assembly boasts enhanced construction and quality, and the method for manufacturing thereof eradicates the need to wrap numerous stator segments with insulation paper before copper wire winding. Leveraging simple manufacturing automation components, the method streamlines the stamping of stator segments in an efficient and space-efficient manner.
[0031] FIG. 3A illustrates a perspective view of a stator segment 300 of a laminated stator assembly for a dual-rotor axial flux motor. The laminated stator assembly is formed of a plurality of stator segments 300 laminated together. Each stator segment 300 has a plurality of stator plates 302 stacked one over another in a vertical arrangement. The stator segment 300 also includes at least one top pole shoe 304 and at least one bottom pole shoe 306 that act as poles for each stator segment 300 to provide better electromagnetic performance, spread out of flux for better uniformity, reduce reluctance of the magnetic path and help to keep the copper coil windings of the each stator segment 300 in place.
[0032] Multiple stator segments 300 may be arranged radially to form the laminated stator assembly. The top pole shoe 304 may be positioned at a top end of the stator plates 302 stacked together. The bottom pole shoe 306 may be positioned at a bottom end of the stator plates 302 stacked together. The stator plates 302 may be stacked together to form the stator segment 300 by any of laser cutting, plasma cutting, stamping and punching processes. Each stator segment 300 may be trapezoidal in shape with the top and bottom pole shoes 304, 306 serving as poles for said stator segment 300. The laminated stator assembly also includes an insulation layer 308 formed on at least one side surface 310 of each of the stator plates 302, after the stator plates 302 are staked together. The insulation layer 308 may include any of an adhesive or a resin adapted to couple the side surfaces 310 of each of the stator plates 302.
[0033] Referring to FIG. 3B, where a stator segment 300 provided with copper wire winding and top and bottom extensions is shown. The winding 312 may be would around the stacked arrangement of the stator plates 302 to form the stator segment 300. The winding 312 may be coupled to the stator segment 300 an adhesive layer 314. The top extension 316 may be placed over the top pole shoe 304, and the bottom extension 318 may be placed over the bottom pole shoe 306. Each of the top and bottom extensions 316, 318 may be adapted to mount magnets thereon with an air-gap formed therebetween.
[0034] FIG. 4A illustrates an exemplary representation of a first configuration of an apparatus 400 for manufacturing the stator segments 300 of the laminated stator assembly. The apparatus 400 may include a conveyor arrangement 402 for conveying the stator plates 302 in a sequential manner towards stacking locations 404, where the stator plates 302 are stacked to form the stator segment 300. The apparatus 400 may also include a robotic arm 406 having a suction head 408 adapted to pick each of the stator plates 302 from the conveyor arrangement 402 and drop or place the picked stator plate 302 to each of the stacking locations 404. The robotic arm 406 may sequentially pick the stator plates 302 and drop them in each stacking location 404 to perform stacking of the stator plates 302 to form the stator segment 300 at each stacking location 404. In an example, the number of robotic arms 406 in the apparatus 400 may be equal to or less than the number of stacking locations 404. Each of the stacking location 404 may be formed between two stator holders 412, with at least one side surface 414 of each of the stator holders 412 facing the stacking location 404 being coated with an insulation layer 308 to enable the insulation layer 308 to be formed on the side surface 310 of each of the stator plates 302, after all the stator plates 302 are staked together. In an implementation as shown in FIG. 4A, the stator holders 412 and the stacking locations 404 are arranged along a linear path. In an example, the thickness of each stator plate 302 may be in the range of 0.15 to 0.35mm.
[0035] The apparatus 400 may include a plurality of tool holders 410, each tool holder 410 configured to face a stacking location 404 of the plurality of stacking locations 404. Each tool holder 410 may be provided with any or a combination of a press/punch, a stamp, a laser cutting tool, a plasma cutting tool, and the likes, to perform a joining operation of joining the stator plates 302 with one another in the vertical arrangement. Each individual stator plates 302 may be produced individually or multiple stator plates 302 may be produced simultaneously. Subsequently, one or all of the stator plates 302 can be picked by one or multiple straightforward suction heads 408 of the robotic arms 406 to place the picked stator plates 302 at desired stacking location 404 arranged between the stator holders 412 along a linear path. In an embodiment as shown in FIG. 4A, the tool holder 410 may include a press configured to press the stacked arrangement of stator plates 302 at the corresponding stacking location 404 to form the stator segment 300. Multiple such stator segments may be radially arranged to form the laminated stator assembly.
[0036] As stated above, the inner side surface 414 of the stator holders 412 facing each stacking location 404 may be coated with the insulation layer 308 containing any of an adhesive or a resin. This process of coating or applying the insulation layer 308 to the side surfaces 414 can be carried out either automatically or manually. As each row of the laminated stator plates 302 is inserted into each stacking location 404, the subsequent row of stator plates 302 may prepared and positioned in the stacking location 404. Once all the laminated stator plates 302 are inserted into the stacking location 404 and the insulation layer 308 is set to the side surfaces 310 of the laminated stator plates 302, the stator segment 300 thus formed may be extracted from the stacking location 404, either manually or through automation. In an implementation, the tool holders 410 may be equipped with electronically or mechanically operated spring push pads, which exert pressure on the laminated stator plates 302 positioned in the stacking location 404 by the suction arm 408. This action ensures that the stator plates 302 are firmly held in place within the stacking location 404, minimizing any gaps to meet the final height requirements.
[0037] Referring to FIG. 4B, where an exemplary representation of a second configuration of the apparatus 450 for manufacturing the stator segments 300 of the laminated stator assembly is shown. The apparatus 450 may include the conveyor arrangement 402 for conveying the stator plates 302 in a sequential manner towards stacking locations 452, where the stator plates 302 are stacked to form the stator segment 300. In the second configuration, the stator plates 302 may be either cut individually or collectively. The apparatus 450 may also include the robotic arm 406 having the suction head 408 adapted to pick each of the stator plates 302 from the conveyor arrangement 402 and drop or place the picked stator plate 302 to each of the stacking locations 452. The robotic arm 406 may sequentially pick the stator plates 302 and drop them in each stacking location 452 to perform stacking of the stator plates 302 to form the stator segment 300 at each stacking location 452. In an example, the number of robotic arms 406 in the apparatus 450 may be equal to or less than the number of stacking locations 452. Each of the stacking location 452 may be formed between two stator holders 454, with at least one side surface 456 of each of the stator holders 454 facing the stacking location 452 being coated with the insulation layer 308 to enable the insulation layer 308 to be formed on the side surface 310 of each of the stator plates 302, after all the stator plates 302 are staked together. In an implementation as shown in FIG. 4B, the stator holders 454 and the stacking locations 452 may be arranged along a periphery of a circular stator holder 458, to allow the stator segments 300 to be formed in the stacking location 452 radially positioned with respect to one another. The stator holders 454 may be integrally formed to the circular stator holder 458.
[0038] The apparatus 450 may include a plurality of tool holders 460, each tool holder 460 radially arranged and configured to face each stacking location 452 of the plurality of stacking locations 452. Each tool holder 460 may be provided with any or a combination of a press, a stamp, a laser cutting tool, a plasma cutting tool, and the likes, to perform a joining operation of joining the stator plates 302 with one another in the vertical arrangement. In an embodiment as shown in FIG. 4B, the tool holder 460 may include a press configured to press the stacked arrangement of stator plates 302 at the corresponding stacking location 452 to form the stator segment 300. Multiple such stator segments may be radially arranged to form the laminated stator assembly. The apparatus 450 may include an alignment wire 462 coupled to protrusions formed in the tool holders 460. The alignment wire 462, when pulled, is adapted pulling each of the tool holders 460 away from the stacking location 452 after stacking of the at least one stator plate 302 at the stacking location 452 is complete.
[0039] In operation, as the circular stator holder 458 rotates to align each stacking location 452 appropriately for the robotic arm 406 to pick and place the stator plate 302 within the stacking location 452, the tool holder 460 associated with said stacking location 452 may retracts from its position. This action can be achieved, for example, by directing the protrusions/pins located atop these tool holders 460 to move away from the stacking location 452 by pulling the alignment wire 462, as illustrated in FIG. 4B. As the stator 302 plates are inserted into the stacking location 452, the tool holders 460 return to their designated positions for securing the stacked plates 302 and prevent them from falling, while also minimizing the gaps between the laminated stator plates 302 to meet the final stator assembly’s height requirements.
[0040] FIG. 5 illustrates a flow chart depicting various processes of a method 500 for manufacturing a laminated stator assembly for a dual-rotor axial flux motor. The method 500 includes a step S502 of coating at least one side surface 414, 456 of each stacking location 412, 454 of a plurality of stacking locations 404, 452 with an insulation layer 308. The method 500 improves the construction and quality of the laminated stator assembly for the dual-rotor axial flux motor. The manufacturing method 500 is fast, simple, and inexpensive. The manufacturing method 500 utilizes the insulation layer 308, such as adhesives, resin, etc., for binding numerous stator laminations/stampings together. Consequently, this eliminates the necessity of wrapping the stator assembly with an insulation paper before winding with copper wires. The utilization of the insulation layer 308 also serves to maintain the integrity of stamping structure of the stator assembly until the copper coils are wound. After the winding process, the structural stability of the stator assembly is primarily upheld by the copper winding itself. In situations of elevated temperatures, the resilience is predominantly derived from the copper windings, while the insulation layer 308 continues to serve its purpose of insulation and reducing eddy losses.
[0041] The method 500, at step S504, includes sequentially picking and dropping at least one stator plate 302 of a plurality of stator plates 302 at the stacking location 404, 452, and a step S506 of stacking the at least one stator plate 302 dropped at the stacking location 404, 452 to form a stator segment 300 of the laminated stator assembly. Each stacking location 404, 452 may be formed between the stator holders 412, 454. In a first configuration, the stator holders 412 may be arranged along a linear path, as shown in FIG. 4A.
[0042] In a second configuration, the stator holders 454 may be arranged along periphery of the circular stator holder 458. The stator holders 454 may be integrally formed to the circular stator holder 458. The step S502 of coating may include applying the insulation layer 308 to at least one side surface 414, 456 of each of the stator holders 412, 454. The step S504 of sequentially picking and dropping of the at least one stator plate 302 may be performed by the robotic arm 406 having the suction head 408 to hold the at least one stator plate 302 and drop the at least one stator plate 302 at the stacking location 404, 452.
[0043] The step S506 of stacking may include joining, by the tool holders 410, 460, the stator plates 302 together to form the stator segments 300 at the stacking locations 404, 452 by any of laser cutting, plasma cutting, stamping and punching processes. Each of the tool holders 410, 460 may face each stacking location 404, 452 of the plurality of stacking locations 404, 452. The step S506 of stacking may also include pulling, by the alignment wire 462, each of the tool holders 460 away from the stacking location 452 after stacking of the at least one stator plate 302 is complete. The step S506 of stacking may also include curing the insulation layer 308 after the plurality of stator plates 302 are stacked together to form the stator segment 300 at each of the stacking locations 404, 452.
[0044] The method allows for efficient manufacturing of the top and the bottom pole shoes in a much easier way and in various desired shapes. The method reliably produces the laminated stator assembly for the dual-rotor axial flux motor, employs simple manufacturing automation components and makes stampings of the stator plates in an efficient and compact manner. The method and the laminated stator assembly thus formed utilize the stator plates to be held together by the insulation layer, while preventing the requirement of laser welding of connecting stator plates with one another.
[0045] While the foregoing describes various embodiments of the disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof. The scope of the disclosure is determined by the claims that follow. The disclosure is not limited to the described embodiments, versions or examples, which are included to enable a person having ordinary skill in the art to make and use the disclosure when combined with information and knowledge available to the person having ordinary skill in the art.
, C , Claims:WE CLAIM:

1. A laminated stator assembly for a dual-rotor axial flux motor, comprising:
a plurality of stator segments (300), each stator segment (300) comprising a plurality of stator plates (302) stacked one over another, at least one top pole shoe (304) and at least one bottom pole shoe (306); and
an insulation layer (308) formed on at least one side surface (310) of each of the plurality of stator plates (302) after said plurality of stator plates (302) are staked together.

2. The laminated stator assembly (300) as claimed in claim 1, wherein the insulation layer (308) comprises any of an adhesive and a resin adapted to couple at least one side surface (310) of each of the plurality of stator plates (302).

3. The laminated stator assembly (300) as claimed in claim 1, wherein the at least one top pole shoe (304) is positioned at a top end of the plurality of stator plates (302) stacked together, and the at least one bottom pole shoe (306) is positioned at a bottom end of the plurality of stator plates (302) stacked together.

4. The laminated stator assembly (300) as claimed in claim 1, wherein the plurality of stator plates (302) are stacked together to form the stator segment (300) by any of laser cutting, plasma cutting, stamping and punching processes.

5. A method (500) for manufacturing a laminated stator assembly for a dual-rotor axial flux motor, the method comprising:
coating (S502) at least one side surface of each stacking location of a plurality of stacking locations with an insulation layer (308);
sequentially picking and dropping (S504) at least one stator plate (302) of a plurality of stator plates (302) at the stacking location; and
stacking (S506) the at least one stator plate (302) dropped at the stacking location to form a stator segment (300) of the stator assembly.

6. The method as claimed in claim 5, wherein each stacking location of the plurality of stacking locations is formed between two stator holders, and wherein the coating (S502) comprises applying the insulation layer (308) to at least one side surface of each of the stator holders, the insulation layer (308) comprising any of an adhesive and a resin adapted to couple at least one side surface (310) of each of the plurality of stator plates (302).

7. The method as claimed in claim 5, wherein the sequentially picking and dropping (S504) of the at least one stator plate (302) is performed by a robotic arm comprising a suction head to hold the at least one stator plate (302) and drop the at least one stator plate (302) at the stacking location.

8. The method as claimed in claim 5, wherein the stacking (S506) comprises:
joining, by a plurality of tool holders, the plurality of stator plates (302) together to form the stator segment (300) by any of laser cutting, plasma cutting, stamping and punching processes, wherein each of the plurality of tool holders faces each stacking location of the plurality of stacking locations;
pulling each of the plurality of tool holders away from the stacking location after stacking (S506) of the at least one stator plate (302) is complete; and
curing the insulation layer after the plurality of stator plates (302) are stacked together to form the stator segment.

9. The method as claimed in claim 6, wherein the stator holders are arranged along a linear path.

10. The method as claimed in claim 6, wherein the stator holders are arranged along periphery of a circular stator holder.