Stator internally cooled electric machine

Abstract

This utility model discloses a motor with internal stator cooling, belonging to the field of motor heat dissipation technology, aiming to solve the problems of difficult heat dissipation of the stator core and the performance limitation caused by temperature rise in external rotor motors. The motor includes a stator, a rotor, and supports at both ends. The stator includes a stator shaft, a stator core, and windings. The rotor is an external rotor with end caps at both ends. The core component is a heat dissipation assembly between the stator shaft and the stator core. This assembly includes a heat dissipation duct, an internal air inlet pipe, and an internal air outlet pipe. The heat dissipation duct consists of an inner cylinder fitted to the stator shaft, an outer cylinder fitted to the stator core, and duct partitions. The partitions divide the space into several heat dissipation ducts, including closed partitions and open partitions. The internal air inlet pipe connects only to a single heat dissipation duct on one side of the closed partition, and the internal air outlet pipe connects only to a single heat dissipation duct on the other side, forming a closed-loop circulation system for heat dissipation airflow in conjunction with a forced ventilation device. This utility model allows the cooling airflow to efficiently circulate and absorb heat from the stator, effectively controlling the motor temperature rise, ensuring motor operating characteristics, and providing support for increased torque density. It is suitable for heat dissipation scenarios of external rotor motors.

Description

Technical Field

[0001] This utility model belongs to the field of motor heat dissipation technology, specifically relating to an external rotor motor with internal stator cooling. Background Technology

[0002] Permanent magnet synchronous motors are widely used due to their high efficiency and high power density. Based on this, a type of permanent magnet synchronous motor with an external rotor and an internal stator core has been developed, namely the external rotor permanent magnet synchronous motor. Compared with the traditional internal rotor permanent magnet synchronous motor of the same volume, its stator core diameter is smaller and the stator core winding end wiring is shorter, saving copper wire. Its rotor diameter is larger, so the rotation arm is larger, making it very suitable for applications with high torque output, such as crane lifting mechanisms and electric vehicles.

[0003] However, the "stator-integrated and compact" structure of the external rotor motor presents a significant heat dissipation bottleneck: under low-speed, high-torque conditions (such as lifting heavy objects or climbing hills at low speeds), the motor load is high and losses are concentrated. The stator core, as the main heat source, is enclosed by the external rotor, and traditional external solutions such as heat sinks and external fans cannot directly address it, leading to heat accumulation and a rapid temperature rise. If "radial openings in the stator core" are used for heat dissipation, the magnetic circuit will be cut off, the magnetic resistance will be increased, the motor torque characteristics will be damaged, and iron losses will be increased, thus negating the structural advantages.

[0004] Other existing solutions also suffer from poor adaptability: external stator cooling pipes are difficult to install due to limited space and have low heat exchange efficiency; water cooling with an integral casing increases the size and weight of the motor, which contradicts the original intention of "compact design". Long-term high temperature can also cause a chain of problems: the winding insulation layer ages faster and shortens its lifespan, and in extreme cases, it can cause the rotor permanent magnet to demagnetize, resulting in torque fluctuations or even failure.

[0005] The current core contradiction in the industry lies in the imbalance between the high torque advantage of external rotor permanent magnet synchronous motors and the insufficient heat dissipation capacity of the stator. If the heat dissipation of the stator core and the control of temperature rise cannot be solved, the increase in torque density will be limited, making it difficult to meet the "high reliability and high torque" requirements of cranes and electric vehicles. There is an urgent need for a stator internal cooling solution that is adapted to its structure to achieve efficient heat dissipation without damaging the magnetic circuit or increasing the volume. Utility Model Content

[0006] To address the problems of difficult heat dissipation of the stator core and the limitation of torque density caused by temperature rise in existing external rotor permanent magnet synchronous motors, a motor with internal stator cooling is provided. This achieves efficient internal heat dissipation of the stator core, controls motor temperature rise, ensures electromagnetic characteristics, and improves torque density and operational reliability.

[0007] To achieve the above objectives, the technical solution of this utility model is as follows:

[0008] An internally cooled stator motor includes a stator, a rotor, and supports at both ends. The stator includes a stator spindle, a stator core, and windings disposed on the stator core. The stator spindle is fixed at both ends to the supports, and the stator core is fixed to the stator spindle. The rotor is an outer rotor, which is sleeved outside the stator, and an annular gap is provided between the inner surface of the rotor and the outer surface of the stator. End caps are fixed at both ends of the rotor, and the end caps are rotatably connected to the stator spindle via rotor bearings.

[0009] A heat dissipation assembly is provided between the outer surface of the stator spindle and the inner surface of the stator core;

[0010] The heat dissipation assembly includes a heat dissipation air duct, an internal air inlet pipe, and an internal air outlet pipe.

[0011] The heat dissipation duct is composed of an inner cylinder, an outer cylinder, and baffles. The inner cylinder is attached to the outer surface of the stator spindle, and the outer cylinder is attached to the inner surface of the stator core. The left and right ends between the inner and outer cylinders are closed. The baffles are evenly distributed around the stator spindle between the inner and outer cylinders, dividing the space between them into several heat dissipation ducts. Each baffle includes a closed baffle and several open baffles. The closed baffle is used to separate and form independent heat dissipation ducts, and the open baffles are used to create airflow paths between adjacent heat dissipation ducts.

[0012] The internal air inlet pipe and the internal air outlet pipe are respectively connected to both ends of the heat dissipation air duct. The output end of the internal air inlet pipe is only connected to a single heat dissipation air duct on the side of the closed partition, and the input end of the internal air outlet pipe is only connected to a single heat dissipation air duct on the other side of the closed partition.

[0013] It also includes a forced ventilation device, the output end of which is connected to the input end of the internal air inlet pipe, for delivering cooling airflow to the heat dissipation duct; the output end of the internal air outlet pipe is connected to one side end cover of the rotor, so that the airflow that has flowed through the heat dissipation duct and absorbed the stator heat is discharged into the atmosphere through the side end cover; thus forming a closed-loop circulation system for heat dissipation airflow.

[0014] The above technical solution has the following advantages: Compared with existing technologies, this stator-cooled motor, by setting up a heat dissipation air duct between the stator spindle and the stator core, consisting of an inner cylinder, an outer cylinder, and air duct partitions containing closed and notched partitions, and cooperating with an internal air inlet pipe, an internal air outlet pipe, and a forced ventilation device that are only connected to a single heat dissipation air duct on both sides of the closed partition, forms a closed-loop circulation system for heat dissipation airflow. The cooling airflow delivered by the forced ventilation device can circulate fully within the heat dissipation air duct along the path guided by the notched partitions to ensure efficient absorption of stator heat, and then be discharged through the internal air outlet pipe and rotor end cover. This not only effectively solves the problem of stator core heat dissipation and precisely controls motor temperature rise, but also retains the original operating characteristics of the external rotor motor by relying on the reasonable air duct structure, providing a stable temperature environment to support the increase of motor torque density, and ensuring efficient and stable operation of the motor under low-speed and high-torque conditions.

[0015] As a further improvement to the above technical solution, the notches of several of the notched partitions are arranged alternately on the left and right along the axial direction of the stator main shaft.

[0016] The above technical solution has the following advantages: By using several notched partitions with notches arranged alternately on the left and right along the stator spindle axis, the cooling airflow can form a zigzag flow trajectory when flowing through adjacent heat dissipation ducts. On the one hand, this significantly prolongs the residence time of the airflow in the heat dissipation duct, forcing the airflow to make more full contact with the inner cylinder of the duct that is attached to the stator spindle, the outer cylinder of the duct that is attached to the stator core, and the wall surface of the duct partition, maximizing the coverage of the heat conduction area of ​​the stator and avoiding heat dissipation dead zones caused by local airflow short circuits. On the other hand, it allows the airflow to evenly absorb heat from different axial positions of the stator, effectively alleviating the thermal stress caused by the axial temperature difference of the stator core, reducing the risk of accelerated aging of the winding insulation layer due to local overheating, further optimizing heat dissipation efficiency and temperature distribution uniformity, and providing more reliable support for the stable control of temperature rise and improvement of torque density of the motor under low-speed, high-torque conditions.

[0017] As a further improvement to the above technical solution, at least nine heat dissipation ducts are evenly distributed along the circumference of the stator spindle, and the included angle between adjacent heat dissipation ducts is equal. The cross-section of each heat dissipation duct is a fan-shaped structure, with the inner arc surface of the fan-shaped structure fitting the outer surface of the stator spindle and the outer arc surface fitting the inner surface of the stator core.

[0018] The above technical solution has the following advantages: First, the uniformly distributed air ducts of no less than nine can fully cover the circumferential area of ​​the stator spindle and stator core, ensuring that local heat dissipation dead zones are avoided due to uneven air duct spacing, and ensuring that heat from different circumferential positions of the stator can be efficiently discharged through the corresponding air ducts. Second, the fan-shaped structure's close fit design can maximize the contact area between the heat dissipation air ducts and the stator spindle and stator core, significantly improving the heat exchange efficiency between the cooling airflow and the heat source, allowing the airflow to absorb heat more fully when flowing through the air ducts. In addition, the equal included angle setting can ensure that the airflow distribution in each air duct is uniform, avoiding the situation of some air ducts being overloaded and some air ducts being underloaded, further enhancing the uniformity and stability of overall heat dissipation, and laying a structural foundation for effectively controlling the motor temperature rise and ensuring the reliability of stator operation.

[0019] As a further improvement to the above technical solution, the overall structure of the internal air inlet pipe is "N" shaped. The stator spindle is provided with a mounting sleeve hole at one end near the internal air inlet pipe. The mounting sleeve hole is located at the central axis of the cross-section of the stator spindle and extends along the axial direction of the stator spindle. The inner diameter of the mounting sleeve hole is adapted to the outer diameter of the internal air inlet pipe, and the input end of the internal air inlet pipe is embedded in the mounting sleeve hole.

[0020] The above technical solution has the following advantages: The "N"-shaped structure can flexibly adapt to the compact internal space of the motor, avoiding components such as stator windings and rotor bearings, thus avoiding installation interference and ensuring the rationality of the overall structural layout; the fitting and embedding design of the mounting sleeve hole at the central shaft and the internal air inlet pipe can not only achieve stable fixation of the internal air inlet pipe, preventing displacement or loosening of the internal air inlet pipe due to vibration during motor operation, but also enhance the sealing fit between the internal air inlet pipe and the stator main shaft, reducing leakage loss of cooling airflow during the transportation process, ensuring that the cooling airflow delivered by the forced ventilation device can be efficiently and accurately introduced into the designated heat dissipation air duct, providing a stable input guarantee for subsequent airflow circulation and heat dissipation, and further improving the operational reliability and efficiency of the overall heat dissipation system.

[0021] As a further improvement to the above technical solution, the forced ventilation device includes a cooler and an external air duct; the output end of the cooler is connected to the input end of the internal air inlet duct through the external air duct.

[0022] The above technical solution has the following benefits: the air cooler can act as an active power source, continuously providing a stable airflow with controllable speed. Compared with natural ventilation, it can significantly improve the delivery intensity of the cooling airflow, meeting the large heat dissipation requirements of the stator core when the low-speed, high-torque motor is running under high load. The external air duct can act as a directional delivery channel, precisely connecting the air cooler and the internal air inlet pipe, effectively reducing leakage loss of the cooling airflow during transmission, ensuring that the airflow output by the air cooler is efficiently and stably introduced into the internal air inlet pipe, and then enters the heat dissipation channel according to the preset path to participate in the circulation and heat absorption. This provides reliable active power support for the entire closed-loop circulation system of the heat dissipation airflow, ensuring continuous and stable heat dissipation efficiency and helping the motor to effectively control the temperature rise.

[0023] As a further improvement to the above technical solution, an exhaust hole is provided on the end cap at one end of the internal air outlet pipe. Several exhaust holes are provided and are evenly distributed around the end cap. The exhaust holes are connected to the output end cavity of the internal air outlet pipe.

[0024] The above technical solution has the following advantages: First, the exhaust holes and internal air ducts form a "main channel + multi-branch channel" heat dissipation structure, which can effectively widen the hot air discharge path and avoid the airflow stagnation problem that may occur when a single internal air duct dissipates heat, significantly improving the efficiency of hot air discharge after absorbing stator heat. Second, the exhaust holes are evenly distributed around the end cover, which allows the hot air to be discharged evenly from different circumferential positions of the end cover, avoiding local overheating of the end cover or stator periphery caused by local airflow accumulation, and optimizing the overall temperature distribution of the motor. At the same time, this structure is adapted to the characteristic of the end cover rotating with the rotor. When the exhaust holes rotate synchronously with the end cover, they can also use slight centrifugal force to assist the airflow to diffuse outward, further enhancing the heat dissipation effect. Moreover, there is no need to add complex drive components, which ensures heat dissipation performance while taking into account the compactness of the motor structure and the reliability of operation.

[0025] As a further improvement to the above technical solution, the end cover is also provided with an oil seal, which is located at the mating clearance between the rotor bearing and the stator spindle.

[0026] The above technical solution has the following advantages: Firstly, it can effectively prevent the lubricating grease inside the rotor bearing from leaking through the mating gap, avoiding grease from seeping into the stator heat dissipation components (such as heat dissipation ducts and internal air inlet pipes) and contaminating the heat dissipation channels, affecting heat exchange efficiency, and at the same time preventing grease from contacting the stator windings and damaging the insulation performance. Secondly, it can block dust, water vapor and other impurities from outside the motor from entering the rotor bearing through the mating gap, avoiding impurities from causing bearing wear and jamming, and extending the bearing service life. In addition, this oil seal setting can also maintain the stability of the operating environment at the mating point between the bearing and the stator spindle, reduce the risk of motor failure due to seal failure, and provide reliable protection for the long-term stable operation of the entire heat dissipation airflow closed-loop system and the motor as a whole. Attached Figure Description

[0027] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the axial cross-sectional structure of the motor in an embodiment of this utility model. Figure 1 ;

[0029] Figure 2 This is a schematic diagram of the axial cross-sectional structure of the motor in an embodiment of this utility model. Figure 2 ;

[0030] Figure 3 This is a schematic diagram of the axial channel structure of the heat dissipation air duct in an embodiment of this utility model;

[0031] Figure 4 This is a schematic diagram of the radial cross-sectional structure of the heat dissipation duct in an embodiment of this utility model;

[0032] Figure 5 This is a schematic diagram of the planar unfolded structure of the heat dissipation duct in an embodiment of this utility model;

[0033] Figure 6 This is a partially enlarged schematic diagram of the connection structure between the internal air inlet pipe and the heat dissipation duct in an embodiment of this utility model.

[0034] Explanation of reference numerals in the attached drawings: 1-Stator, 11-Stator spindle, 12-Stator core, 2-Rotor, 21-End cover, 211-Exhaust hole, 3-Support, 41-Cooling duct, 41a-Inner cylinder of the duct, 41b-Outer cylinder of the duct, 41c-Duct partition, 411a-Closed partition, 411b-Notched partition, 411c-Notch, 42-Internal air inlet pipe, 43-Internal air outlet pipe, 44-Air cooler, 45-External air duct, 5-Cooling duct, 6-Oil seal. Detailed Implementation

[0035] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0036] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0037] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0038] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; 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; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0039] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0040] Example 1

[0041] like Figures 1 to 6As shown, this embodiment provides a motor with internal stator cooling, including a stator 1, a rotor 2, and two end supports 3; the stator 1 includes a stator main shaft 11, a stator core 12, and windings disposed on the stator core 12; the two ends of the stator main shaft 11 are fixed on the supports 3, and the stator core 12 is fixed on the stator main shaft 11; the stator core 12 is composed of several stator laminations with the same structure stacked along the axial direction of the stator main shaft 11; the rotor 2 is an outer rotor, and several magnetic sheets are arranged longitudinally and transversely on the inner surface of the rotor 2, the rotor 2 is sleeved on the outside of the stator 1, and an annular gap is provided between the inner surface of the rotor 2 and the outer surface of the stator 1; end caps 21 are fixed at both ends of the rotor 2, and the end caps 21 are rotatably connected to the stator main shaft 11 through rotor bearings;

[0042] A heat dissipation assembly is provided between the outer surface of the stator spindle 11 and the inner surface of the stator core 12;

[0043] The heat dissipation assembly includes a heat dissipation duct 41, an internal air inlet pipe 42, and an internal air outlet pipe 43;

[0044] The heat dissipation duct 41 is composed of an inner duct cylinder 41a, an outer duct cylinder 41b, and a duct partition 41c. The inner duct cylinder 41a is attached to the outer surface of the stator spindle 11, and the outer duct cylinder 41b is attached to the inner surface of the stator core 12. The left and right ends between the inner duct cylinder 41a and the outer duct cylinder 41b are set as closed structures. The duct partition 41c is evenly distributed between the inner duct cylinder 41a and the outer duct cylinder 41b along the circumference of the stator spindle 11. The duct partition 41c divides the space between the two to form a number of heat dissipation ducts 5. The duct partition 41c includes a closed partition 411a and a number of notched partitions 411b. The closed partition 411a is used to separate and form independent heat dissipation ducts, and the notched partitions 411b are used to form an airflow path between adjacent heat dissipation ducts.

[0045] The internal air inlet pipe 42 and the internal air outlet pipe 43 are respectively connected to both ends of the heat dissipation air duct 41. The output end of the internal air inlet pipe 42 is only connected to a single heat dissipation air duct 5 on the side of the closed partition 411a, and the input end of the internal air outlet pipe 43 is only connected to a single heat dissipation air duct 5 on the other side of the closed partition 411a.

[0046] It also includes a forced ventilation device, the output end of which is connected to the input end of the internal air inlet pipe 42, for delivering cooling airflow to the heat dissipation duct 5; the output end of the internal air outlet pipe 43 is connected to one side end cover 21 of the rotor 2, so that the airflow that has flowed through the heat dissipation duct and absorbed the heat of the stator 1 is discharged into the atmosphere through the side end cover 21; thus forming a closed-loop circulation system for the heat dissipation airflow.

[0047] By setting a heat dissipation air duct 41 between the stator spindle 11 and the stator core 12, consisting of an inner cylinder 41a, an outer cylinder 41b, and an air duct partition 41c containing a closed partition 411a and a notched partition 411b, and in conjunction with an internal air inlet pipe 42, an internal air outlet pipe 43, and a forced ventilation device that are only connected to a single heat dissipation air duct 5 on both sides of the closed partition 411a, a closed-loop circulation system for heat dissipation airflow is formed. The cooling airflow delivered by the forced ventilation device can circulate fully within the heat dissipation air duct 41 along the path guided by the notched partition 411b, efficiently absorbing heat from the stator 1, and then being discharged through the internal air outlet pipe 43 and the rotor 2 end cover 21. This not only effectively solves the heat dissipation problem of the stator core 12 and precisely controls the motor temperature rise, but also retains the original operating characteristics of the external rotor motor by relying on the reasonable air duct structure, providing a stable temperature environment to support the improvement of motor torque density, and ensuring the efficient and stable operation of the motor under low-speed and high-torque conditions.

[0048] In this embodiment, the notches 411c of the several notched partitions 411b are arranged alternately on the left and right along the axial direction of the stator main shaft 11. This alternating arrangement of the notches 411c on the left and right along the axial direction of the stator main shaft 11 ensures that the cooling airflow forms a zigzag flow trajectory when flowing through adjacent heat dissipation ducts 5. This significantly prolongs the residence time of the airflow within the heat dissipation duct 5, forcing the airflow to more fully contact the inner cylinder 41a of the duct that adheres to the stator main shaft 11 and the stator core 12. The outer cylinder 41b of the air duct and the wall of the air duct partition 41c maximize the coverage of the heat conduction area of ​​the stator 1, avoiding heat dissipation dead zones caused by local airflow short circuits. On the other hand, it allows the airflow to absorb heat from different axial positions of the stator 1 evenly, effectively alleviating the thermal stress caused by the axial temperature difference of the stator core 12, reducing the risk of accelerated aging of the winding insulation layer due to local overheating, further optimizing heat dissipation efficiency and temperature distribution uniformity, and providing more reliable support for the motor to stably control temperature rise and improve torque density under low speed and high torque conditions.

[0049] In this embodiment, at least nine heat dissipation ducts 5 are evenly distributed around the stator spindle 11, and the included angle between adjacent heat dissipation ducts 5 is equal, all being 40°. The cross-section of each heat dissipation duct 5 is a fan-shaped structure, with the inner arc surface of the fan-shaped structure fitting the outer surface of the stator spindle 11 and the outer arc surface fitting the inner surface of the stator core 12.

[0050] The uniformly distributed air ducts, numbering no fewer than nine, can fully cover the circumferential area of ​​the stator spindle 11 and stator core 12, ensuring that local heat dissipation dead zones are avoided due to uneven air duct spacing, and ensuring that heat from different circumferential positions of the stator 1 can be efficiently discharged through the corresponding air ducts 5. The fan-shaped fitting design maximizes the contact area between the heat dissipation air ducts 5 and the stator spindle 11 and stator core 12, significantly improving the heat exchange efficiency between the cooling airflow and the heat source, allowing the airflow to absorb heat more fully when flowing through the air ducts. In addition, the equal included angle setting ensures that the airflow distribution in each air duct is uniform, avoiding overload in some air ducts and insufficient airflow in others, further enhancing the uniformity and stability of overall heat dissipation, and laying a structural foundation for effectively controlling the motor temperature rise and ensuring the operational reliability of the stator 1.

[0051] In this embodiment, the internal air inlet pipe 42 has an overall structure of "N" shape. The stator spindle 11 is provided with a mounting sleeve hole at one end near the internal air inlet pipe 42. The mounting sleeve hole is located at the central axis of the cross section of the stator spindle 11 and extends along the axial direction of the stator spindle 11. The inner diameter of the mounting sleeve hole is adapted to the outer diameter of the internal air inlet pipe 42, and the input end of the internal air inlet pipe 42 is embedded in the mounting sleeve hole.

[0052] The "N"-shaped internal air inlet duct 42 can flexibly adapt to the compact space inside the motor, avoiding components such as stator windings and rotor bearings, thus preventing installation interference and ensuring the rationality of the overall structural layout. The fitting and embedding design of the mounting sleeve hole at the central shaft with the internal air inlet duct 42 can not only achieve stable fixation of the internal air inlet duct 42, preventing displacement or loosening of the internal air inlet duct 42 due to vibration during motor operation, but also enhance the sealing fit between the internal air inlet duct 42 and the stator spindle 11, reducing leakage loss of cooling airflow during the transportation process, ensuring that the cooling airflow delivered by the forced ventilation device can be efficiently and accurately introduced into the designated heat dissipation air duct 5, providing a stable input guarantee for subsequent airflow circulation and heat dissipation, and further improving the operational reliability and efficiency of the overall heat dissipation system.

[0053] In this embodiment, the forced ventilation device includes a cooler 44 and an external air duct 45; the output end of the cooler 44 is connected to the input end of the internal air inlet duct 42 through the external air duct 45.

[0054] The air cooler 44 can serve as an active power source, continuously providing a stable airflow with controllable speed. Compared to natural ventilation, it can significantly improve the delivery intensity of the cooling airflow, meeting the large heat dissipation needs of the stator core 12 when the low-speed, high-torque motor is running under high load. The external air duct 45 can serve as a directional delivery channel, precisely connecting the air cooler 44 and the internal air inlet duct 42, effectively reducing leakage loss of the cooling airflow during transmission, ensuring that the airflow output by the air cooler 44 is efficiently and stably introduced into the internal air inlet duct, and then enters the heat dissipation channel along a preset path to participate in the circulation and heat absorption. This provides reliable active power support for the entire closed-loop circulation system of the heat dissipation airflow, ensuring continuous and stable heat dissipation efficiency and helping the motor to effectively control the temperature rise.

[0055] In this embodiment, an exhaust hole 211 is provided on the end cap 21 near one end of the internal air outlet pipe 43. Several exhaust holes 211 are provided and are evenly distributed around the end cap 21. The exhaust holes 211 are connected to the output end cavity of the internal air outlet pipe 43.

[0056] The heat dissipation structure, consisting of a main channel and multiple branch channels, is formed by several exhaust holes 221 and the internal air outlet duct 43. This ensures that the hot airflow discharge path is effectively widened, avoiding the airflow stagnation problem that may occur when dissipating heat through a single internal air outlet duct, and significantly improving the efficiency of hot airflow discharge after absorbing heat from the stator 1. Furthermore, the exhaust holes 221 are evenly distributed along the circumference of the end cover, ensuring that the hot airflow can be discharged evenly from different circumferential positions of the end cover 21, avoiding local overheating of the end cover 21 or the area around the stator 1 caused by local airflow accumulation, and optimizing the overall temperature distribution of the motor. At the same time, this structure is adapted to the characteristic that the end cover rotates with the rotor 2. When the exhaust holes 221 rotate synchronously with the end cover 21, they can also use a slight centrifugal force to assist the airflow to diffuse outward, further enhancing the heat dissipation effect. Moreover, no additional complex drive components are required, ensuring heat dissipation performance while taking into account the compactness of the motor structure and operational reliability.

[0057] In this embodiment, the end cover 21 is also provided with an oil seal 6, which is located at the mating gap between the rotor bearing and the stator spindle 11.

[0058] By installing an oil seal 6 at the mating clearance between the rotor bearing and the stator spindle 11, the leakage of lubricating grease inside the rotor bearing from the mating clearance can be effectively prevented, avoiding grease seepage into the stator heat dissipation components, contamination of the heat dissipation channels, and impact on heat exchange efficiency. It also prevents grease from contacting the stator windings and damaging their insulation performance. Furthermore, it blocks dust, moisture, and other impurities from outside the motor from entering the rotor bearing through the mating clearance, preventing bearing wear and jamming and extending bearing life. In addition, the oil seal 6 maintains a stable operating environment at the mating point between the bearing and the stator spindle 11, reducing the risk of motor failure due to seal failure, and providing reliable protection for the long-term stable operation of the entire heat dissipation airflow closed-loop system and the motor as a whole.

[0059] The working process of this utility model:

[0060] By starting the air cooler 44, the cooling airflow is delivered through the external air duct 45 and the internal air inlet duct 42 to a single heat dissipation air duct 5 on the side of the closed partition 411a in the heat dissipation air duct cylinder 41. The cooling airflow flows axially in the heat dissipation air duct 5. After encountering the notched partition 411b, it enters the adjacent heat dissipation air duct 5 through the notch 411c. Guided by the alternating notches 411b and notches 411c, the airflow circulates in a zigzag pattern among the multiple heat dissipation air ducts 5. During the process, it fully contacts the inner cylinder 41a (fitting the stator spindle 11), the outer cylinder 41b (fitting the stator core 12), and the partition 41c, efficiently absorbing the heat generated by the stator 1. The heat-absorbing airflow finally gathers in the single heat dissipation air duct 5 on the other side of the closed partition 411a, is delivered to the corresponding end cover 21 through the internal air outlet duct 43, and is then evenly discharged into the atmosphere through multiple exhaust holes 211 on the end cover 21, completing one heat dissipation cycle.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. A stator-cooled motor, comprising a stator (1), a rotor (2), and two end supports (3); the stator (1) comprises a stator spindle (11), a stator core (12), and windings disposed on the stator core (12); the two ends of the stator spindle (11) are fixedly disposed on the supports (3), and the stator core (12) is fixedly disposed on the stator spindle (11); the rotor (2) is an outer rotor, the rotor (2) is sleeved outside the stator (1), and an annular gap is provided between the inner surface of the rotor (2) and the outer surface of the stator (1); end caps (21) are fixedly disposed at both ends of the rotor (2), and the end caps (21) are rotatably connected to the stator spindle (11) through rotor bearings; characterized in that: A heat dissipation assembly is provided between the outer surface of the stator spindle (11) and the inner surface of the stator core (12); The heat dissipation assembly includes a heat dissipation duct (41), an internal air inlet pipe (42), and an internal air outlet pipe (43); The heat dissipation duct (41) is composed of an inner duct cylinder (41a), an outer duct cylinder (41b), and a duct baffle (41c). The inner duct cylinder (41a) is attached to the outer surface of the stator spindle (11), and the outer duct cylinder (41b) is attached to the inner surface of the stator core (12). The left and right ends between the inner duct cylinder (41a) and the outer duct cylinder (41b) are set as closed structures. The duct baffle (41c) is located around the stator spindle (11). The air duct partition (41c) is evenly distributed between the inner cylinder (41a) and the outer cylinder (41b) of the air duct. It divides the space between the two to form a number of heat dissipation air ducts (5). The air duct partition (41c) includes a closed partition (411a) and a number of notched partitions (411b). The closed partition (411a) is used to separate and form independent heat dissipation air ducts. The notched partitions (411b) are used to form an airflow path between adjacent heat dissipation air ducts. The internal air inlet pipe (42) and the internal air outlet pipe (43) are respectively connected to both ends of the heat dissipation air duct (41), wherein: the output end of the internal air inlet pipe (42) is only connected to a single heat dissipation air duct (5) on the side of the closed partition (411a), and the input end of the internal air outlet pipe (43) is only connected to a single heat dissipation air duct (5) on the other side of the closed partition (411a); It also includes a forced ventilation device, the output end of which is connected to the input end of the internal air inlet pipe (42) for delivering cooling airflow to the heat dissipation duct (5); the output end of the internal air outlet pipe (43) is connected to a side end cover (21) of the rotor (2) so that the airflow that has flowed through the heat dissipation duct and absorbed the heat of the stator (1) is discharged into the atmosphere through the side end cover (21); thus forming a closed-loop circulation system for heat dissipation airflow.

2. The stator-cooled motor according to claim 1, characterized in that: The notches of the notched partitions (411b) are arranged alternately on the left and right along the axial direction of the stator main shaft (11).

3. The stator-cooled motor according to claim 1, characterized in that: At least nine heat dissipation ducts (5) are evenly distributed around the stator main shaft (11), and the included angle between adjacent heat dissipation ducts (5) is equal. The cross-section of each heat dissipation duct (5) is fan-shaped, with the inner arc surface of the fan-shaped duct fitting the outer surface of the stator main shaft (11) and the outer arc surface fitting the inner surface of the stator core (12).

4. The stator-cooled motor according to claim 1, characterized in that: The internal air inlet pipe (42) has an overall "N" shape. The stator spindle (11) has a mounting sleeve hole at one end near the internal air inlet pipe (42). The mounting sleeve hole is located at the central axis of the cross-section of the stator spindle (11) and extends axially along the stator spindle (11). The inner diameter of the mounting sleeve hole is adapted to the outer diameter of the internal air inlet pipe (42). The input end of the internal air inlet pipe (42) is embedded in the mounting sleeve hole.

5. A stator-cooled motor according to claim 4, characterized in that: The forced ventilation device includes a cooler (44) and an external air duct (45); the output end of the cooler (44) is connected to the input end of the internal air inlet duct (42) through the external air duct (45).

6. A stator-cooled motor according to claim 1, characterized in that: An exhaust hole (211) is provided on the end cap (21) at one end of the internal air outlet pipe (43). The exhaust holes (211) are arranged in a plurality of manner and are evenly distributed around the end cap (21). The exhaust holes (211) are respectively connected to the output end cavity of the internal air outlet pipe (43).

7. A stator-cooled motor according to claim 1, characterized in that: The end cover (21) is also provided with an oil seal (6), which is located at the mating clearance between the rotor bearing and the stator spindle (11).

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