A slotless ac motor structure based on a few iron cores

Abstract

This utility model discloses a slotless AC motor structure based on a reduced-core design, comprising a housing, a stator module, a partial core module, and a rotor module. The housing includes a main body and a base plate. The stator module is built into the housing and includes an annular non-magnetic frame and coils. The partial core module includes several cores, which are mounted one-to-one on a core mounting bracket, with air gaps between adjacent cores. This slotless AC motor structure aims to solve problems such as significant cogging effect, excessive core weight, and inflexible magnetic circuit in traditional motor structures. The motor eliminates the traditional slotted stator structure, adopting a combination design of slotless coils and a partial magnetic core. While ensuring effective control of the magnetic flux path, it significantly reduces motor weight, manufacturing complexity, and improves dynamic response performance.

Description

Technical Field

[0001] This utility model belongs to the field of AC motor technology, specifically relating to a non-slotted AC motor structure based on fewer iron cores. Background Technology

[0002] In traditional AC motor designs (including brushless DC motors and permanent magnet synchronous motors), the stator is typically composed of laminated iron cores with multiple stator slots into which the electromagnetic coils are embedded. The iron core serves not only to construct the magnetic circuit but also to improve magnetic flux density and energy conversion efficiency. However, this structure also presents the following problems:

[0003] 1. Severe cogging effect: The presence of core slots easily causes torque fluctuations and noise;

[0004] 2. Increased moment of inertia and weight: The use of a single iron core results in a large motor mass, which is not conducive to lightweight systems such as aircraft and robots;

[0005] 3. Complex winding manufacturing: The coil needs to be embedded in the slot, which is difficult to manufacture;

[0006] 4. Concentrated electromagnetic losses: Especially at high speeds, iron losses are significant, reducing system efficiency.

[0007] To address these issues, existing technologies have developed two types of improved structures:

[0008] (1) Coreless Motor: The iron core is completely eliminated, and only the winding and permanent magnet are retained. Although the weight is greatly reduced, the magnetic flux density is low, the output torque is limited, and it is easily disturbed due to the lack of an effective magnetic circuit.

[0009] (2) Slotless Motor: The iron core is retained but the slot structure is eliminated, which improves the cogging effect, but the iron core volume is still large and the structure is not flexible enough.

[0010] Despite some progress in these improved structures, problems such as non-concentrated magnetic circuits, insufficient structural strength, poor heat dissipation, or high manufacturing costs still exist.

[0011] Therefore, there is an urgent need for a new type of motor design that combines the advantages of slotless windings with the magnetic permeability of local iron cores. This design should maintain lightweight construction and reduce cogging effects while still possessing a certain degree of flux control capability, thereby achieving a good balance between performance and structure. Utility Model Content

[0012] The main objective of this invention is to provide a non-slotted AC motor structure with a reduced iron core, aiming to solve problems such as significant cogging effect, excessive iron core weight, and inflexible magnetic circuit in traditional motor structures. The motor eliminates the traditional slotted stator structure, employing a combination of non-slotted coils and a locally conductive magnetic core. This significantly reduces motor weight, manufacturing complexity, and improves dynamic response performance while ensuring effective control of the magnetic flux path.

[0013] To achieve the above objectives, this utility model provides a non-slotted AC motor structure based on a reduced-core design, comprising a housing, a stator module, a partial core module, and a rotor module, wherein:

[0014] The housing includes a main body and a base plate. The base plate is fixedly installed on the bottom of the main body (for easy quick installation and disassembly via snap-fit ​​or other installation methods). The top inner side of the main body is provided with a first roller mounting groove and the inner side of the base plate is provided with a second roller mounting groove.

[0015] The stator module is built into the housing and includes an annular non-magnetic frame (such as plastic or lightweight alloy) and a coil. The annular non-magnetic frame has a coil mounting slot on its outer side and several core mounting brackets facing the center on its inner side, with a spacing between adjacent core mounting brackets. The coil is wound in the coil mounting slot in an external winding manner.

[0016] The local iron core module includes several iron cores, each of which is installed in a corresponding manner on the iron core mounting frame and an air gap is provided between adjacent iron cores.

[0017] The rotor module includes a first roller, a second roller, and an output shaft. The first roller is installed in the first roller mounting slot and the second roller is installed in the second roller mounting slot. One end of the output shaft is installed in the second roller and the other end of the output shaft passes through the first roller and the main body in sequence. The output shaft is sleeved with a permanent magnet and the permanent magnet is surrounded by the annular non-magnetic skeleton.

[0018] As a further preferred technical solution to the above technical solution, the bottom of the main body is provided with several fixing holes (for fixing the entire motor in a preset position).

[0019] As a further preferred embodiment of the above technical solution, the main body is provided with a plurality of first limiting posts facing the base plate and the base plate is provided with a plurality of second limiting posts facing the first limiting posts, the first limiting posts and the second limiting posts being aligned one by one.

[0020] As a further preferred technical solution of the above technical solution, the coil is provided with a plurality of limiting holes, the first limiting post is inserted into one end of the corresponding limiting hole and the second limiting post is inserted into the other end of the corresponding limiting hole (so that the stator module is stably installed on the housing).

[0021] As a further preferred technical solution to the above technical solution, the iron core can be detachably installed on the iron core mounting frame (including installation by means of slots, buckles, epoxy encapsulation or magnetic attraction, etc.).

[0022] Compared with existing AC motor structures that commonly use all-core slotted winding motors or completely coreless winding motors, this invention, by adopting a non-slotted coil structure combined with a partially distributed iron core design, effectively overcomes several bottlenecks of traditional solutions while maintaining motor performance, and has the following advantages and beneficial effects:

[0023] 1. Significantly reduces motor weight, achieving a lightweight structural design:

[0024] Traditional slotted stators require a single iron core lamination to form a complete magnetic circuit, resulting in a large overall motor mass, which makes it difficult to meet the strict weight requirements of portable, highly mobile platforms (such as drones and power tools). This invention eliminates the continuous iron core slot structure, arranging only a small number of magnetic guiding units in key magnetic flux paths. While ensuring magnetic performance, it greatly reduces the amount of ferromagnetic material used, effectively reducing the overall weight of the machine.

[0025] 2. Effectively reduces cogging torque, improves torque smoothness and operating noise control:

[0026] Traditional slotted winding motors are prone to cogging effect, where the rotor experiences periodic disturbances as the magnetic poles pass through the stator slots, causing torque pulsation and mechanical noise. This invention employs a slotless winding arrangement combined with a flux-guided local core configuration to achieve a continuous and smooth magnetic field distribution, significantly reducing cogging torque. This improves motor operational stability and reduces vibration and noise, making it particularly suitable for applications requiring quiet operation (such as gimbals and electric balance scooters).

[0027] 3. Simplify winding manufacturing and assembly processes to improve production efficiency:

[0028] Traditional slotted winding processes require winding the coil into stator slots, which is complex, inefficient, and carries risks of winding damage and insulation failure. This invention employs an externally wound or suspended non-slotted winding structure, allowing the coil to be directly formed and installed on an open frame or mold. The winding structure is clear, assembly is convenient, and the process is simple, making it suitable for modular manufacturing and mass production.

[0029] 4. Controllable magnetic flux path, balancing efficient energy conversion and thermal management:

[0030] Although this invention eliminates the traditional continuous iron core, it still guides the main magnetic flux closed path by embedding local magnetic guiding units (such as C-shaped iron cores or soft magnetic pillars) at key magnetic circuit locations, thus balancing magnetic field concentration and heat dissipation. This composite design of "magnetic performance enhancement + air gap buffering" maintains good magnetic coupling efficiency while optimizing magnetic flux distribution and heat dissipation, making it suitable for high-frequency drive, long-term operation, and other applications.

[0031] 5. Improve motor response speed and dynamic performance:

[0032] Due to the reduced moment of inertia, minimal cogging interference, and flexible magnetic flux adjustment in the motor structure of this invention, the motor can quickly respond to external control commands under low load conditions, improving the overall dynamic performance of the system. It is particularly suitable for applications requiring high response speeds, such as precision servo control and flight control systems.

[0033] 6. High degree of freedom in electromagnetic design, facilitating structural innovation and control integration:

[0034] This invention "releases" the windings from the core slots, allowing for greater flexibility in design parameters such as winding shape, spatial distribution, and pole arrangement, making it adaptable to different external rotor and disc motor structures. Simultaneously, it provides more expandability for future integration of power drive, magnetic field sensing, and other modules, demonstrating excellent platformization and secondary development potential. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the structure of this utility model.

[0036] Figure 2 This is a cross-sectional view of the present invention.

[0037] Figure 3 This is a cross-sectional view of the present invention.

[0038] Figure 4 This is a structural schematic diagram of the present invention (shell hidden).

[0039] Figure 5 This is a structural schematic diagram of the stator module of this utility model.

[0040] Figure 6 This is a schematic diagram of the rotor module of this utility model.

[0041] The reference numerals in the accompanying drawings include: 100, housing; 110, main body; 111, first roller mounting groove; 112, fixing hole; 113, first limiting post; 120, base plate; 121, second roller mounting groove; 122, second limiting post; 200, stator module; 210, annular non-magnetic frame; 211, iron core mounting bracket; 220, coil; 221, limiting hole; 300, partial iron core module; 310, iron core; 400, rotor module; 410, first roller; 420, second roller; 430, output shaft; 431, permanent magnet. Detailed Implementation

[0042] The following description is intended to disclose the present invention so that those skilled in the art can implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art. The basic principles of the present invention defined in the following description can be applied to other embodiments, modifications, improvements, equivalents, and other technical solutions that do not depart from the spirit and scope of the present invention.

[0043] This utility model discloses a non-slotted AC motor structure based on a reduced iron core. The specific embodiments of the utility model are further described below with reference to preferred embodiments.

[0044] In the embodiments of this utility model, those skilled in the art will note that the preset positions and other features involved in this utility model can be considered as prior art.

[0045] Preferred embodiment.

[0046] like Figure 1-6 As shown, this utility model discloses a non-slotted AC motor structure based on a reduced-core design, comprising a housing 100, a stator module 200, a partial core module 300, and a rotor module 400, wherein:

[0047] The housing 100 includes a main body 110 and a bottom plate 120. The bottom plate 120 is fixedly installed on the bottom of the main body 110 (for quick installation and disassembly via snap-fit ​​or other installation methods). The top inner side of the main body 110 is provided with a first roller mounting groove 111 and the inner side of the bottom plate 120 is provided with a second roller mounting groove 121.

[0048] The stator module 200 is built into the housing 100 and includes an annular non-magnetic frame 210 (such as plastic or lightweight alloy) and a coil 220. The annular non-magnetic frame 210 has a coil mounting groove (not shown) on its outer side and a plurality of core mounting brackets 211 facing the center on its inner side, with a spacing between adjacent core mounting brackets 211. The coil 220 is wound in the coil mounting groove in an external winding manner.

[0049] The local core module 300 includes a plurality of cores 310, each of which is installed in a corresponding manner on the core mounting frame 211 and an air gap is provided between adjacent cores 310.

[0050] The rotor module 400 includes a first roller 410, a second roller 420, and an output shaft 430. The first roller 410 is installed in the first roller mounting groove 111, and the second roller 420 is installed in the second roller mounting groove 121. One end of the output shaft 430 is installed in the second roller 420, and the other end of the output shaft 430 passes through the first roller 410 and the main body 110 in sequence. The output shaft 430 is sleeved with a permanent magnet 431, and the permanent magnet 431 is surrounded by the annular non-magnetic skeleton 210.

[0051] Specifically, the bottom of the main body 110 is provided with several fixing holes 112 (for fixing the entire motor in a preset position).

[0052] More specifically, the main body 110 is provided with a plurality of first limiting posts 113 facing the base plate 120 and the base plate 120 is provided with a plurality of second limiting posts 122 facing the first limiting posts 113, and the first limiting posts 113 and the second limiting posts 122 are aligned one by one.

[0053] Furthermore, the coil 220 is provided with a plurality of limiting holes 221, the first limiting post 113 is inserted into one end of the corresponding limiting hole 221 and the second limiting post 122 is inserted into the other end of the corresponding limiting hole 221 (so that the stator module is securely installed on the housing).

[0054] Furthermore, the iron core 310 can be detachably installed on the iron core mounting bracket 211 (including installation by means of slots, buckles, epoxy encapsulation or magnetic attraction).

[0055] Regarding this utility model:

[0056] The housing serves as a fixed support frame outside the motor, featuring standard mounting holes; it provides a mounting base, mechanical support, and partial heat dissipation. Instead of encapsulating the traditional stator core within the housing structure, this invention uses the housing as part of a non-magnetic support skeleton, enhancing lightweight design.

[0057] For the stator module, the frame is made of lightweight non-magnetic material (such as aluminum alloy or engineering plastic) to support the winding (coil) structure; it has a ring or polygonal frame layout and no traditional stator slots; the multi-phase windings are hollow-wound and arranged circumferentially along the frame, with the coils fixed to the surface of the open support and isolated from the support by insulation treatment; the windings use multi-strand enameled wire or thick copper wire, and can be equipped with an epoxy impregnation structure to enhance strength; the stator uses a ring-shaped non-magnetic frame (such as plastic or lightweight alloy); the outer edge of the frame has evenly arranged coil mounting positions; the coils are wound on the outside of this frame in an external winding manner, rather than embedded in the iron core slots; the stator frame is fixed to the inner ring of the housing and positioned by screws or clips; each winding is led out to the control terminal through a PCB or ribbon cable; in traditional motors, the stator coils are embedded in the iron core slots, making it difficult to prefabricate the windings and complex to assemble; this utility model, through an external winding slotless structure, allows the windings to be formed independently, facilitating modular assembly.

[0058] For the localized iron core module, several iron cores or soft magnetic pillars are configured on the back of each winding or in the magnetic field concentration area; the iron cores do not form a continuous stator iron core, but are locally distributed and used only for concentrated magnetic flux; an air gap is retained between each iron core to avoid the formation of large-area eddy current losses; the traditional iron core is a closed magnetic circuit formed by continuous silicon steel sheets, while this utility model adopts a "localized magnetic conduction" design; effectively reducing iron losses, making the magnetic flux more controllable, and maintaining a high torque density.

[0059] For the rotor module, the rotor adopts a permanent magnet structure (NS poles) and can be in the form of an external rotor or an internal rotor; the permanent magnet can be made of neodymium iron boron material and is glued or embedded in the rotor; a stable air gap is maintained between the permanent magnet and the stator to form the working magnetic flux. The rotor structure of this utility model can be adapted to the traditional external rotor permanent magnet design; however, due to the optimization of the stator magnetic circuit, it requires a lower magnetic flux density, allowing for a reduction in the volume or number of magnets.

[0060] The working principle of this utility model is as follows:

[0061] When alternating current (or a PWM control signal provided by the driver) is sequentially applied to the three-phase windings, a rotating magnetic field is formed in space. This rotating magnetic field interacts magnetically with the permanent magnets on the rotor, driving the rotor to rotate.

[0062] Although the stator windings are not embedded in the core slots, the magnetic flux can be partially guided and concentrated by the help of local core blocks set on the back or at a specific angle, thereby improving the effective magnetic field density and motor efficiency.

[0063] The localized iron core achieves both enhanced magnetic performance and lightweight structure without increasing the overall magnetic circuit closure iron loss.

[0064] Description of the working process of this utility model:

[0065] (1) In the initial stage of power-on, the controller performs phase sequence control on the winding according to the target speed or load requirements to form a rotating magnetic field;

[0066] (2) The stator coils and rotor magnets generate electromagnetic torque, causing the rotor to start rotating;

[0067] (3) The local iron core plays a magnetic guiding role at the key magnetic flux path, which effectively improves the magnetic flux coupling efficiency;

[0068] (4) The rotor rotates, driving the load to run, and the motor enters a steady state;

[0069] (5) As needed, the speed / torque can be adjusted using closed-loop control mode.

[0070] It is worth mentioning that the technical features such as the preset position involved in this utility model patent application should be regarded as prior art. The specific structure, working principle and possible control method and spatial arrangement of these technical features can be adopted by conventional choices in the field, and should not be regarded as the inventive point of this utility model patent. This utility model patent will not be further elaborated in detail.

[0071] For those skilled in the art, modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A slotless AC machine structure based on a few-cores, characterized by, It includes a housing, a stator module, a partial core module, and a rotor module, wherein: The housing includes a main body and a bottom plate. The bottom plate is fixedly installed on the bottom of the main body. The top inner side of the main body is provided with a first roller mounting groove and the inner side of the bottom plate is provided with a second roller mounting groove. The stator module is built into the housing and includes an annular non-magnetic frame and a coil. The outer side of the annular non-magnetic frame is provided with a coil mounting slot and the inner side of the annular non-magnetic frame is provided with a plurality of iron core mounting brackets facing the center. There is a gap between adjacent iron core mounting brackets. The coil is wound in the coil mounting slot in an external winding manner. The local iron core module includes several iron cores, each of which is installed in a corresponding manner on the iron core mounting frame and an air gap is provided between adjacent iron cores. The rotor module includes a first roller, a second roller, and an output shaft. The first roller is installed in the first roller mounting slot and the second roller is installed in the second roller mounting slot. One end of the output shaft is installed in the second roller and the other end of the output shaft passes through the first roller and the main body in sequence. The output shaft is sleeved with a permanent magnet and the permanent magnet is surrounded by the annular non-magnetic skeleton.

2. A slotless AC machine structure based on few ferries according to claim 1, characterized in that, The bottom of the main body is provided with several fixing holes.

3. A slotless AC machine structure based on few ferries according to claim 2, characterized in that, The main body is provided with a plurality of first limiting posts facing the base plate and the base plate is provided with a plurality of second limiting posts facing the first limiting posts, the first limiting posts and the second limiting posts being aligned one by one.

4. A slotless AC machine structure based on few ferries according to claim 3, characterized in that, The coil is provided with several limiting holes, the first limiting post is inserted into one end of the corresponding limiting hole and the second limiting post is inserted into the other end of the corresponding limiting hole.

5. A slotless AC machine structure based on few ferries according to claim 1, characterized in that, The iron core can be detachably installed on the iron core mounting frame.

Images