An AC motor with a high-efficiency heat dissipation structure

Abstract

This invention discloses an AC motor with a high-efficiency heat dissipation structure, aiming to solve the heat dissipation bottleneck problem of traditional AC motors in compact, enclosed environments caused by narrow air gaps and thermal boundary layer effects. The core of this invention lies in providing an AC motor with a high-efficiency heat dissipation structure. This system includes an airflow excitation unit driven by rotor kinetic energy and an airflow directional delivery unit. The airflow excitation unit converts the rotor's rotational motion into periodic air compression through a magnetostrictive reciprocating mechanism; the airflow directional delivery unit efficiently delivers compressed air to the air gap region through a multi-stage pressurization structure, a spiral flow guiding structure, and an adaptive airflow guiding structure. This system achieves active disruption of the thermal boundary layer within the air gap and enhanced heat transfer without increasing the air gap or relying on external forced air cooling, significantly improving the motor's heat dissipation efficiency and operational reliability. It is particularly suitable for applications with limited space and requiring frequent forward and reverse rotation, such as washing machines.

Description

Technical Field

[0001] This invention relates to the field of electric motors, and in particular to an AC motor with a high-efficiency heat dissipation structure. Background Technology

[0002] AC motors, especially squirrel-cage induction motors, are widely used as the drive core in household appliances such as washing machines due to their simple structure, low cost, and reliable operation. However, washing machine motors operate for extended periods in enclosed, humid, and poorly ventilated chambers, resulting in extremely poor heat dissipation conditions. If the large amount of heat generated during frequent starts and stops, full-load operation, and forward / reverse switching (mainly copper losses in the stator windings and iron losses in the core) cannot be dissipated in time, the winding temperature will continuously rise, accelerating the aging of insulation materials, severely impacting the motor's lifespan and operational reliability, and even causing malfunctions.

[0003] Traditional AC motors primarily rely on natural convection and radiation for heat dissipation from the stator housing surface. Some models incorporate a centrifugal fan at the end of the shaft for forced air cooling of the stator housing's outer surface. However, these heat dissipation methods have inherent limitations:

[0004] Long heat dissipation path and high thermal resistance: Heat is generated from the internal rotor and must pass through multiple thermal resistances such as the rotor core, air gap, stator, internal air, and stator housing before it can be dissipated to the outside, resulting in low efficiency.

[0005] The air gap heat dissipation bottleneck is prominent: the air gap between the stator and rotor (usually 0.3-1.5mm) is a critical heat dissipation path, but it is filled with air, which has extremely poor thermal conductivity. Within the narrow air gap, the airflow shearing effect generated by the rotor rotation is limited, and a stable "thermal boundary layer" is easily formed on the stator surface, which severely hinders the transfer of heat to the air gap air, becoming the core bottleneck of heat dissipation.

[0006] External forced air cooling has limited effectiveness and drawbacks: while adding an external fan can enhance heat dissipation from the stator housing, its direct cooling effect on the motor interior, especially the air gap area, is weak. Furthermore, the fan increases axial dimensions, operating noise, and power consumption, contradicting the design trend of compact and quiet washing machines.

[0007] Unable to adapt to complex working conditions: The frequent forward and reverse rotation of the washing machine motor means that any traditional blade design that relies on the rotor rotation direction for effective airflow may fail in one rotation direction, resulting in uneven heat dissipation.

[0008] In order to improve heat dissipation in the air gap, existing technologies have also attempted to increase the air gap size to improve air flow. However, this directly leads to an increase in motor magnetic reluctance, an increase in excitation current, and a decrease in power factor and efficiency. It comes at the cost of electromagnetic performance and is not advisable.

[0009] Therefore, there is an urgent need to develop an innovative heat dissipation solution that can actively, directly, and efficiently enhance the heat dissipation capacity of the motor's air gap area without changing the motor's basic electromagnetic design (such as without increasing the air gap), without significantly increasing the motor's size and noise, and while adapting to frequent forward and reverse operation conditions, thus fundamentally breaking through the technical bottleneck of traditional heat dissipation modes. Summary of the Invention

[0010] The purpose of this invention is to overcome the shortcomings of existing technologies and provide an AC motor with a highly efficient heat dissipation structure. Without affecting the core electromagnetic performance of the motor or significantly increasing its size and cost, it achieves efficient, directional, and adaptive cooling of the air gap region, significantly reducing motor temperature rise and improving its operational reliability and lifespan, making it particularly suitable for harsh applications such as washing machines.

[0011] To achieve the above objectives, the present invention provides the following technical solution:

[0012] An AC motor with a high-efficiency heat dissipation structure includes a stator assembly, a rotor assembly, end covers, and an active heat dissipation system integrated inside the motor. The active heat dissipation system comprises two core components: an airflow activation unit and an airflow directional delivery unit. These components work together to form a highly efficient heat dissipation enhancement loop.

[0013] The airflow excitation unit efficiently and quietly converts the mechanical energy of the rotor assembly's rotation into kinetic energy (pressure pulsation) that can be used for heat dissipation. Its main components include:

[0014] Drive unit: Fixed on the rotating shaft of the rotor assembly, rotating synchronously with the rotor assembly, and equipped with a first magnetic action unit.

[0015] Response unit: Fixed to the end cover or stator assembly, and arranged axially opposite to the drive unit.

[0016] Elastic deformation section: connected to the response section, usually a corrugated mechanism with elastic recovery capability, which together with the response section defines a variable volume chamber, and a second magnetic action section is provided in the elastic deformation section.

[0017] The airflow excitation unit operates on the principle of non-contact magnetic coupling: when the drive unit rotates, a periodically changing axial magnetic force (such as alternating repulsion and attraction) is generated between the first and second magnetic action parts. This alternating magnetic force drives the elastic deformation part to undergo regular axial reciprocating deformation, thereby periodically compressing and expanding the air in the chamber, generating air pressure pulsations with a specific frequency, and then pumping the compressed air out of the chamber as cooling air. This design avoids wear and noise caused by mechanical contact, and the energy conversion is direct and efficient.

[0018] The function of the airflow directional delivery unit is to "process" and "deliver" the raw pressure pulses generated by the airflow excitation unit, ensuring that they act precisely and effectively on the heat dissipation bottleneck area—the air gap. It is a functionally integrated module containing the following key substructures, each with progressively layered and synergistic functions:

[0019] Airflow compression and boosting structure: To overcome the problem of insufficient single-blow air pressure caused by the limited axial space of the motor, this structure is set in the response section. It includes at least two compression chambers with gradually decreasing volume arranged along the airflow delivery direction, connected to each other by a first one-way valve. The pulsating airflow from the excitation unit passes through each chamber sequentially, achieving step-by-step compression and boosting. This process significantly improves the static and dynamic pressure of the output airflow, ensuring that the airflow has sufficient energy to penetrate the air gap inlet and penetrate deep into the interior, solving the problem of "short stroke and weak follow-through" of the cooling airflow.

[0020] Airflow guiding structure: Connected to the outlet of the pressurization structure, it is responsible for guiding the pressurized airflow to the target area. It includes a guide tube whose outlet extends to the air gap inlet. Furthermore, by setting spiral guide vanes inside the guide tube, the outflowing high-pressure airflow generates a rotational motion, forming a vortex. The rotation direction of this vortex is preset to be the same as the working rotation direction of the rotor assembly. The vortex has stronger radial mixing ability and axial penetration force, and can extend the flow distance in the narrow space of the air gap through the Coanda effect, thereby more thoroughly destroying the thermal boundary layer and achieving uniform and efficient enhanced heat transfer. It should be noted that, due to the frequent forward and reverse reversal of the washing machine motor, the effective working time of the airflow guiding structure in this solution is usually half of its total working time.

[0021] Adaptive airflow guide structure: Located on the end face of the rotor assembly facing the air gap inlet, it ensures that the cooling airflow is effectively captured and guided under different directions. Its typical configuration consists of multiple V-shaped guide vane groups arranged in a ring, each group of vanes in a V-shape. This symmetrical structure ensures that regardless of whether the rotor assembly rotates forward or backward, there is always a vane surface that can efficiently receive the cooling airflow from the guide tube and guide it into the air gap, perfectly adapting to the frequent forward and reverse rotation requirements of the washing machine motor. It should be noted that when the rotation direction of the cooling air delivered by the airflow guide mechanism is the same as the rotation direction of the rotor assembly, the adaptive airflow guide structure can enhance the spiral intensity of the airflow.

[0022] Airflow confinement structure (optional): Fixed to the stator assembly and surrounding the adaptive airflow guide structure, typically a conical air ring. Its function is to concentrate the airflow directed by the guide vanes, reduce lateral dispersion, and further improve the concentration and efficiency of airflow entering the air gap.

[0023] Beneficial effects:

[0024] 1. This invention transforms passive heat dissipation into active directional turbulence, directly targeting and forcibly disrupting the core bottleneck of the air gap thermal boundary layer, thereby significantly improving heat exchange efficiency and effectively reducing the core temperature rise of the motor.

[0025] 2. In this invention, the heat dissipation system is built into the motor, making full use of the end space and eliminating the need for a large external fan or complex air duct, making it particularly suitable for applications such as washing machines where installation space is strictly limited.

[0026] 3. In this invention, the improvement of electrode heat dissipation capacity is achieved entirely through mechanical and fluid means, without the need to increase the air gap, thus fully maintaining the original excellent electromagnetic performance and efficiency of the motor.

[0027] 4. The unique V-shaped air guide vane design in this invention ensures that the heat dissipation system can work stably and efficiently under any operating condition of frequent forward and reverse rotation of the motor, resulting in high reliability.

[0028] 5. Magnetic drive has no mechanical wear and low noise; the system has no additional vulnerable parts and its lifespan matches that of the motor body. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the structure of the present invention;

[0030] Figure 2 yes Figure 1 A sectional view;

[0031] Figure 3 This is a schematic diagram of the combination of the airflow excitation unit and the airflow compression and boosting structure in this invention;

[0032] Figure 4 This is a schematic diagram of an airflow compression and boosting structure;

[0033] Figure 5 yes Figure 4 A longitudinal sectional view;

[0034] Figure 6 yes Figure 4 Circumferential sectional view;

[0035] Figure 7 This is a schematic diagram of the drive unit;

[0036] Figure 8 This is a schematic diagram of the rotor assembly;

[0037] Figure 9 This is a cross-sectional schematic diagram of the rotor assembly and the stator assembly;

[0038] Figure 10 This is a schematic diagram of the structure marked I;

[0039] Figure 11 This is a schematic diagram of the structure marked II;

[0040] Figure 12 This is a schematic diagram of the structure marked III;

[0041] Figure 13 This is a schematic diagram of the structure marked IV.

[0042] Reference numerals: 100. Stator assembly; 200. Rotor assembly; 201. Shaft; 300. Air gap; 400. End cover; 500. Airflow activation unit; 510. Drive unit; 511. Mounting bracket; 512. First magnetic action unit; 520. Response unit; 530. Elastic deformation unit; 531. Second magnetic action unit; 600. Airflow directional delivery unit; 610. Airflow compression and pressurization structure; 611. First compression chamber; 612. Second compression chamber; 613. Outlet chamber; 614. Partition plate; 615. First one-way valve; 620. Airflow guiding structure; 621. Guide tube; 622. Spiral guide vane; 700. Adaptive airflow guiding structure; 710. V-shaped guide vane assembly; 800. Airflow constraint structure. Detailed Implementation

[0043] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0044] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0045] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0046] Reference Figures 1-13This embodiment provides an AC induction motor with a high-efficiency heat dissipation structure for use in a washing machine.

[0047] The motor includes conventional components such as a stator assembly 100, a rotor assembly 200, a shaft 201, and an end cover 400. An annular air gap 300 is formed between the stator assembly 100 and the rotor assembly 200. The core improvement of this invention lies in the integration of an active cooling system.

[0048] An active cooling system consists of the following components:

[0049] Airflow arousal unit 500: This airflow arousal unit 500 is located at the motor drive end (it can also be arranged at the non-drive end depending on space). Figures 4-7 As shown, the airflow arousal unit 500 includes a drive unit 510, which is a mounting bracket 511 coaxially fixed with the rotating shaft 201. The mounting bracket 511 can be made of, for example, plastic or a non-magnetized metal material. The mounting bracket 511 is designed in the shape of a fan blade with multiple inclined blades. On the end face of the mounting bracket 511 near the end cover 400, at least one set of permanent magnets (with N polarity) are embedded as the first magnetic action part 512, which are arranged at intervals along the circumference.

[0050] The response unit 520 is a rigid housing fixed inside the end cap 400 or the stator assembly 100. A flexible silicone or rubber elastic deformation part 530 (corrugated mechanism) covers the open end of the housing and together with the housing forms an initial cavity. On the end face of the elastic deformation part 530 facing the drive unit 510, a ring of permanent magnets (all with the same polarity, for example, all N poles) is embedded as a second magnetic action part 531.

[0051] When the motor starts, the rotor assembly 200 drives the shaft 201 and the mounting bracket 511 to rotate. The first magnetic action part 512 (N pole) on the mounting bracket 511 periodically sweeps across the second magnetic action part 531 (N pole) on the response part 520. When like poles (NN) are opposite each other, a repulsive force is generated, which pushes the elastic deformation part 530 to deform into the cavity, compressing the air in the cavity and causing the air in the cavity to tend to be expelled.

[0052] It should be noted that relying on the self-recovery of the elastic deformation section 530 as the basis for axial reciprocating motion typically results in a response speed that cannot match the drive cycle generated by a high-speed rotating motor (1400 rpm). Therefore, at least two sets of first magnetic action sections 512 can be configured, with adjacent first magnetic action sections 512 having opposite polarities. When the motor starts, in addition to the repulsion between like poles (NN), there is also mutual attraction between opposite poles (SN), which pulls the elastic deformation section 530 back out of the cavity, restoring the cavity volume. Thus, for each rotation of the rotor, the elastic deformation section 530 completes at least one reciprocating motion, generating periodic air pressure pulsations within the cavity at a frequency that is an integer multiple of the motor speed. Simultaneously, the rotating fan-shaped mounting bracket 511 also serves as an auxiliary ventilation unit, allowing external air to be blown into the motor through the ventilation holes on the end cover 400.

[0053] Airflow directional delivery unit 600: This airflow directional delivery unit 600 is integrated with the response unit 520 of the airflow arousal unit 500 and is mainly used to process and deliver aroused air pulsations.

[0054] First, the airflow compression and boosting structure 610 is located inside the housing of the response unit 520. For example... Figure 5 As shown, the internal space of the housing is divided into three axially arranged chambers (in the airflow direction) by two partitions 614. The space of these three chambers gradually decreases, in the following order: the first compression chamber 611 (adjacent to the elastic deformation section 530, with the largest volume), the second compression chamber 612, and the final outlet chamber 613 (with the smallest volume). A first one-way valve 615 (such as a duckbill valve) is installed on the partitions 614, allowing airflow only from upstream to downstream. The reciprocating motion of the elastic deformation section 530 first draws external air into the first compression chamber 611 through the second one-way valve on the elastic deformation section 530, and then compresses it into the second compression chamber 612 during the compression stroke. Because the second compression chamber 612 has a smaller volume, the air is further compressed. In the next compression stroke, the air in the second compression chamber 612 is then compressed into the outlet chamber 613, which has the smallest volume, achieving a third compression. Through these three stages of progressive pressurization, the originally weak air pulsation is transformed into an intermittent high-pressure cooling airflow with significantly increased pressure.

[0055] Secondly, the airflow guiding structure 620 is connected to the air outlet of the outlet chamber 613. For example... Figure 6 , Figure 12As shown, it includes a curved guide tube 621, whose inlet communicates with the outlet chamber 613, and whose outlet is precisely aligned with the inlet region of the air gap 300. Specifically, a spiral guide vane 622 is cast or embedded inside the guide tube 621. When the high-pressure airflow passes through the guide tube 621, it is forcibly twisted by the spiral guide vane 622, forming a jet with a strong rotational component (vortex). The rotation direction of this vortex is designed to be the same as one of the rotation directions of the washing machine motor during washing.

[0056] Adaptive airflow guiding structure 700 and airflow constraint structure 800. For example... Figures 8-11 , Figure 13 As shown, multiple circumferentially distributed V-shaped guide vane groups 710 are machined or installed on the end face of the rotor assembly 200 facing the air gap inlet. Each vane group consists of two metal or plastic blades that protrude from the rotor end face and are arranged in a V-shape. The two blades that make up the V-shaped guide vane group 710 are tilted and folded down in the opposite direction of rotation. At the same time, a trumpet-shaped airflow constraint structure 800 is fixedly installed on the corresponding end face of the stator assembly 100, which covers the periphery of the V-shaped guide vane group 710.

[0057] When the motor is running, the active cooling system starts simultaneously. The high-pressure cooling airflow generated by the airflow arousal unit 500 and the airflow directional delivery unit 600 is ejected in a swirling form through the guide pipe 621. This swirling flow has two key characteristics: high pressure ensures that it can overcome the air gap inlet resistance; rotational motion allows it to utilize fluid viscosity to more effectively adhere to the air gap wall and propagate forward, extending the flow distance.

[0058] After the swirling jet is ejected, it is immediately captured by the rotating V-shaped guide vane assembly 710 on the rotor end face. Due to the symmetry of the V-shaped structure, regardless of whether the rotor rotates forward or backward, there is always a vane surface that can effectively "catch" the jet from the guide tube and convert its kinetic energy into flow directed towards the air gap. This is a key adaptive design for the frequent forward and reverse rotation of the washing machine motor, ensuring effective airflow guidance under all operating conditions. The airflow constraint structure 800 acts like a "flow collector," constraining the airflow directed from the guide vanes, preventing it from being uselessly lost to both sides, and further concentrating it into the air gap.

[0059] Ultimately, this enhanced and directed cooling airflow, with a velocity and kinetic strength several orders of magnitude higher than natural convection within the air gap, violently impacts and disrupts the thermal boundary layer on the stator surface, efficiently carrying away the accumulated heat. Simultaneously, the spiral advance of the airflow within the air gap enhances radial and circumferential mixing, resulting in more uniform heat dissipation.

[0060] This invention constructs a complete, efficient, and adaptive active air gap heat dissipation chain through a series of highly coordinated and progressively functional techniques: "magnetostrictive reciprocating excitation → multi-stage compression and pressurization → helical flow shaping → adaptive capture and introduction → constrained centralized delivery." This solution fundamentally changes the traditional motor's reliance on passive heat dissipation, achieving a qualitative leap in heat dissipation capacity without compromising performance, demonstrating outstanding creativity and significant practical value.

[0061] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. For example, the number of compression and boosting stages can be adjusted as needed; the shape of the guide tube and the design of the guide vanes can be optimized; the angle of the V-shaped blades can be adjusted, etc. Therefore, the scope of protection of the present invention should be determined by the scope of the claims. Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An alternating current motor with high-efficiency heat dissipation structure, comprising a stator assembly (100), a rotor assembly (200) and an end cover (400), and an air gap (300) between the stator assembly (100) and the rotor assembly (200), characterized in that: It also includes an active cooling system integrated inside the motor; The active cooling system includes: The airflow excitation unit (500) generates periodic air pressure pulsations by utilizing the rotational kinetic energy of the rotor assembly (200); The airflow directional delivery unit (600) receives the air pressure pulsation and converts it into a directional high-pressure cooling airflow, and delivers the high-pressure cooling airflow to at least one inlet region of the air gap (300) to enhance airflow within the air gap and disrupt the thermal boundary layer. The airflow arousal unit (500) includes: The drive unit (510) rotates synchronously with the rotor assembly (200) and is provided with at least one first magnetic action unit (512). The response unit (520) is fixed to the end cap (400) or the stator assembly (100) and is axially opposite to the drive unit (510); An elastic deformation section (530) is connected to the response section (520) to form a cavity, and is provided with a second magnetic action section (531) that interacts with the first magnetic action section (512). The elastic deformation section (530) is able to generate axial reciprocating deformation under the periodically changing magnetic force between the first magnetic action section (512) and the second magnetic action section (531), thereby generating the air pressure pulsation in the cavity.

2. The AC motor with a high-efficiency heat dissipation structure according to claim 1, characterized in that: The airflow directional delivery unit (600) includes an airflow compression and boosting structure (610), which is located within the response unit (520). The airflow compression and boosting structure (610) includes at least two compression chambers (611) arranged sequentially along the airflow delivery direction and with gradually decreasing volume. A first one-way valve (615) is provided between adjacent compression chambers to allow airflow to pass through in one direction. The air pressure pulsation drives the airflow to pass through each compression chamber sequentially to achieve step-by-step pressurization, forming the high-pressure cooling airflow.

3. The AC motor with a high-efficiency heat dissipation structure according to claim 2, characterized in that: The airflow directional delivery unit (600) further includes an airflow guiding structure (620), which is connected to the outlet of the airflow compression and boosting structure (610) and is used to guide the high-pressure cooling airflow to the inlet region of the air gap (300).

4. The AC motor with a high-efficiency heat dissipation structure according to claim 3, characterized in that: The airflow guiding structure (620) includes: The guide tube (621) has its inlet connected to the outlet of the airflow compression and boosting structure (610), and its outlet extends to the inlet of the air gap (300); The internal flow channel of the guide tube (621) is configured to generate a rotational motion component in the airflow passing through it.

5. The AC motor with a high-efficiency heat dissipation structure according to claim 4, characterized in that: The guide tube (621) is provided with a spiral guide vane (622) inside, which is used to generate a swirling flow of air, and the rotation direction of the swirling flow is the same as the preset rotation direction of the rotor assembly (200).

6. The AC motor with a high-efficiency heat dissipation structure according to claim 2, characterized in that: The first magnetic action part (512) on the drive part (510) includes at least one set of permanent magnets with alternating polarities, so as to generate alternating repulsive and attractive forces on the second magnetic action part (531) during rotation, thereby driving the elastic deformation part (530) to reciprocate.

7. The AC motor with a high-efficiency heat dissipation structure according to claim 1, characterized in that: It also includes an adaptive airflow guiding structure (700), which is disposed on the end face of the rotor assembly (200) facing the inlet of the air gap (300), for effectively guiding the cooling airflow from the airflow directional delivery unit (600) into the air gap (300) when the motor is rotating forward or in reverse.

8. The AC motor with a high-efficiency heat dissipation structure according to claim 7, characterized in that: The adaptive air guide structure (700) includes multiple circumferentially arranged V-shaped air guide blade groups (710), each V-shaped air guide blade group (710) consists of two blades arranged in a V shape, the opening of the V shape facing away from the rotation center of the rotor assembly (200) and towards the inlet of the air gap (300).

9. The AC motor with a high-efficiency heat dissipation structure according to claim 8, characterized in that: It also includes an airflow constraint structure (800), which is fixed to the stator assembly (100) and arranged around the adaptive airflow guide structure (700) to gather the airflow induced by the adaptive airflow guide structure (700) and reduce its dissipation outside the air gap.

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