Ventilation cooling structure of high-power-density outer rotor permanent magnet motor

Abstract

The invention belongs to the technical field of permanent magnet motor cooling, and relates to a high-power-density outer rotor permanent magnet motor forced air cooling integrated structure which comprises a hollow shaft, a stator iron core, a winding coil, a rotor iron core, a permanent magnet, a machine shell, a heat conduction element, a fan and a spray cooling device. The machine shell is rotationally arranged on the hollow shaft through the upper end cover and the lower end cover. The permanent magnet is arranged on the inner side of the rotor iron core; the fan is fixedly arranged on the upper end cover; the heat conducting element is arranged on the stator iron core and the coil; and the spray cooling device is arranged on the inner side of the hollow shaft. The water atomization cooling device is arranged in the hollow shaft, atomized liquid is sprayed out, atomized liquid water is evenly distributed on the surfaces of the cooling fins, the atomized liquid is vaporized to absorb heat, more heat is taken away after the atomized liquid absorbs heat and is liquefied in unit time, and the cooling effect is improved; and meanwhile, through cooperative cooling of the heat conduction element and the fan, the overall cooling effect of the device is better.

Description

Technical Field

[0001] The invention belongs to the technical field of permanent magnet motor cooling, and in particular relates to a ventilation cooling structure of a high power density outer rotor permanent magnet motor. Background Art

[0002] Among the ten major equipment fields proposed by Made in China 2025, eight are related to high-performance motor systems, and six of them involve high-power density drive motors, including high-end CNC machine tools and robots, aerospace equipment, marine engineering equipment and high-tech ships, advanced rail transportation equipment, energy-saving and new energy vehicles, and biological and high-performance medical devices. It can be said that a large number of drive motor devices are required in many fields involving national energy security, aerospace and military equipment, and the application prospects are very broad. This brings new challenges to the electromagnetic design, structural design and heat dissipation design of the motor. The increase in the power density of permanent magnet motors means the increase in the internal winding copper loss, stator iron loss and permanent magnet eddy current loss of the motor, which directly causes the increase in the internal heat generation and heat flux density of the motor. The excessive temperature rise of the motor has become an urgent problem to be solved. The service life of the permanent magnet motor and the reliability of its operation depend on the steady-state temperature rise of the motor. Only by designing a reasonable cooling system and enhancing the heat dissipation capacity of the motor can the various indicators of the motor be reasonably allocated and the motor design work be completed. If the motor does not have a suitable heat dissipation system, the temperature of the motor will be too high, which will cause a series of effects on the motor. Therefore, studying and analyzing the cooling and heat dissipation structure of permanent magnet synchronous motors is of great significance to solving the problem of motor overheating. Summary of the invention

[0003] Purpose of the present invention: In order to overcome the deficiencies of the prior art, a high power density outer rotor permanent magnet motor ventilation and cooling structure is provided to solve the problems of increased internal heat generation and heat flux density of the permanent magnet motor, excessive motor temperature rise, etc.

[0004] To achieve the above object, the present invention provides the following technical solutions: A high power density outer rotor permanent magnet motor ventilation cooling structure, comprising a hollow shaft, a stator core, a winding coil, a rotor core, a permanent magnet, a housing, a heat conducting element, a fan and a spray cooling device. The stator core is provided with an assembly groove. The winding coil is arranged in the winding slot of the stator core; The hollow shaft is located inside the stator core, and the hollow shaft is provided with a mounting protrusion matching the assembly groove, and the hollow shaft is fixedly connected to the stator core via the mounting protrusion; The housing is arranged along the circumference of the rotor core, the housing is fixedly connected to the outer side of the rotor core, and the housing has an end cover b and an end cover a, and the housing is rotatably arranged on the hollow shaft through the end cover b and the end cover a; The permanent magnet is arranged on the inner side of the rotor core; the fan is fixedly arranged on the end cover b; the heat conducting element is arranged on the stator core and the winding coil; the spray cooling device is arranged on the inner side of the hollow shaft.

[0005] As a further description of the above scheme, the permanent magnet is bonded and fixed to the inner side of the rotor core, the hollow shaft includes a hollow shaft upper section, a hollow shaft middle section and a hollow shaft lower section, the hollow shaft upper section and the hollow shaft lower section are both provided with assembly grooves, the hollow shaft middle section is provided with assembly protrusions corresponding to the assembly grooves, and the hollow shaft upper section, the hollow shaft middle section and the hollow shaft lower section are all fixed by the cooperation of the assembly grooves and the assembly protrusions.

[0006] As a further description of the above scheme, the heat conductive element is a heat pipe, and the heat pipe includes a flat heat pipe and an L-shaped heat pipe. The flat heat pipe and the L-shaped heat pipe are both made of aluminum nitride material. The width of the flat heat pipe and the L-shaped heat pipe are both 4-6 mm, and the thickness is both 2-3 mm.

[0007] As a further description of the above scheme, the spray cooling device is arranged on the upper section of the hollow shaft, and the spray cooling device includes a nozzle, a water pipe and a water injection pipe. The water pipe is fixedly arranged along the inner wall of the upper section of the hollow shaft. There are multiple nozzles, and each of the nozzles is arranged on the water pipe. One end of the water injection pipe is connected to the water pipe, and the other end of the water injection pipe extends to the outside of the lower section of the hollow shaft and is connected to an external water source.

[0008] As a further description of the above scheme, the fan includes a loading end cover, a connecting key and fan blades, the loading end cover is an annular structure, and the loading end cover is fixed on the top surface of the end cover b; there are multiple fan blades, the fan blades are arranged on the inner side of the loading end cover, and the fan blades are arranged at intervals along the circumference of the loading end cover; the connecting key is fixedly set at the center of the loading end cover.

[0009] As a further description of the above scheme, the flat heat pipe and the L-shaped heat pipe are provided in plurality, each of the flat heat pipes having a flat heat pipe heat absorption end and a flat heat pipe heat release end, the flat heat pipe heat absorption end is connected to the winding coil, and the flat heat pipe heat release end extends along the radial direction of the stator core to the hollow area inside the hollow shaft; each of the L-shaped heat pipes has an L-shaped heat pipe heat absorption end and an L-shaped heat pipe heat release end, the L-shaped heat pipe heat absorption end is fixedly connected to the yoke of the stator core, and the L-shaped heat pipe heat release end extends along the radial direction of the stator core to the hollow area inside the hollow shaft, and each of the L-shaped heat pipe heat release end and the flat heat pipe heat release end is connected to a heat sink.

[0010] As a further description of the above solution, the stator core, winding coil and heat pipe are potted as a whole with epoxy resin.

[0011] As a further description of the above solution, the L-shaped heat pipe and the flat heat pipe are both fixed to the heat sink by tinning, and a windshield is provided at one end of the hollow shaft adjacent to the loading end cover.

[0012] Advantages and effects 1. The present invention makes full use of the advantages of high thermal conductivity of the heat pipe, inserts the heat absorbing end of the heat pipe into the heat generating part of the motor, and extends the heat releasing end of the heat pipe radially along the drive motor to the air area of ​​the motor hollow shaft, and is connected with a heat sink to increase the heat dissipation area. The heat can be efficiently transferred to the external space of the permanent magnet motor through forced ventilation cooling and heat dissipation of the motor self-fan. The proposed cooling structure can effectively reduce the volume, weight and cost of the drive motor, and has great application and economic significance for the cooling system analysis and heat dissipation analysis of high power density permanent magnet motors.

[0013] 2. The present invention adopts a high power density outer rotor permanent magnet motor forced air cooling integrated structure. One side of the driving motor is installed and fixed by a flange and a hollow shaft, and the other side is connected to a loading end cover. One end of the loading end cover is connected to the load, and the other end is connected to the fan blade, and rotates together with the motor, thereby realizing forced ventilation cooling of the heat sink in the hollow shaft, reducing the temperature rise of the motor, and eliminating the need for an additional fan for ventilation and cooling, thereby improving the working efficiency of the drive system.

[0014] 3. In order to achieve better cooling and heat dissipation, the cooling structure design is carried out for the main heat source of the motor in a targeted manner. One end of the heat pipe is inserted into the yoke of the stator core of the permanent magnet motor, which can effectively carry away the stator core loss. The number of heat pipes corresponds to the number of stator slots. In order to reduce the thickness of the stator core yoke, the heat pipe adopts a flat structure; the winding end is connected to multiple heat pipes, which can effectively carry away the winding copper loss. The number of heat pipes corresponds to the number of winding coils. In order to increase the contact area between the heat pipe and the winding, the heat pipe adopts a flat structure. At the same time, in order to improve the mechanical strength of the stator core part and enhance the heat transfer performance, each section of the stator core, winding, heat pipe, etc. is encapsulated as a whole through epoxy resin to avoid poor contact between the parts and poor heat transfer effect.

[0015] 4. In order to improve the heat dissipation effect of the cooling structure, a water atomization cooling device is installed inside the hollow shaft to indirectly spray atomized liquid. The atomized liquid water is evenly distributed on the surface of the heat sink. The atomized liquid vaporizes and absorbs heat. After absorbing heat and liquefying per unit time, the atomized liquid takes away more heat, thereby improving the heat dissipation effect.

[0016] 5. Due to the excessive copper loss on the winding coils of the high-power-density outer rotor permanent magnet motor, the heat generated by the windings is concentrated in the internal space of the motor, and the heat cannot be effectively transferred to the outside through the casing. The heat dissipation cooling system proposed in the patent of this invention can effectively solve the problem of excessive temperature rise in the winding part, and efficiently transfer the heat on the winding coils and the stator core to the external space, which can effectively suppress the maximum temperature rise of the permanent magnet motor. At the same time, the permanent magnets of the outer rotor permanent magnet motor are located on the outside of the motor, and the eddy current losses induced on the permanent magnets transfer heat to the outside through the rotor core and the casing, avoiding the risk of demagnetization of the permanent magnets due to excessive temperature.

[0017] 6. The present invention adopts a high power density outer rotor permanent magnet motor forced air cooling integrated structure. The permanent magnet can directly adopt a surface mount structure. The installation process is simple and easy to implement. The rotor yoke is thin, which is conducive to reducing the weight of the rotor core and further improving the motor power density.

[0018] 7. Considering the problem of heat pipe assembly, the present invention adopts segmented processing of the hollow shaft, and divides the hollow shaft into three sections: upper, middle and lower. Each section is provided with assembly grooves and connecting protrusions, which can more conveniently realize the connection of the heat pipe. This design can not only improve the assembly efficiency of the heat pipe, but also ensure the connection reliability and stability of the heat pipe. At the same time, the segmented processing of the hollow shaft can also reduce the overall length of the hollow shaft, reduce the overall weight of the motor, and improve the operating efficiency and reliability of the motor. In addition, the design of the assembly grooves and connecting protrusions can also increase the strength and rigidity of the hollow shaft, and improve the operating stability and life of the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1A three-dimensional exploded view of a forced air cooling integrated structure of a high power density outer rotor permanent magnet motor according to an embodiment of the present invention; Figure 2 A schematic diagram of the three-dimensional structure of a hollow shaft according to an embodiment of the present invention; Figure 3 for Figure 2 sectional view of Figure 4 A three-dimensional schematic diagram of the middle section of a hollow shaft according to an embodiment of the present invention; Figure 5 A three-dimensional schematic diagram of the upper section of a hollow shaft according to an embodiment of the present invention; Figure 6 A schematic diagram of the upper section assembly groove of a hollow shaft according to an embodiment of the present invention; Figure 7 A three-dimensional schematic diagram of the lower section of a hollow shaft according to an embodiment of the present invention; Figure 8 A three-dimensional schematic diagram of the connection between a heat pipe and a heat sink according to an embodiment of the present invention; Fig. 9 A three-dimensional schematic diagram of a stator core according to an embodiment of the present invention; Fig.10 A three-dimensional schematic diagram of a bent heat pipe according to an embodiment of the present invention; Fig.11 A front view of the stator core, windings and heat pipe assembly according to an embodiment of the present invention; Fig.12 This is a rear view of the stator core, windings and heat pipes of an embodiment of the present invention; Fig.13 This is a schematic diagram of epoxy resin potting according to an embodiment of the present invention; Fig.14 It is a three-dimensional schematic diagram of the assembly of the rotor core, permanent magnets and housing according to an embodiment of the present invention; Fig.15 for Fig.14 sectional view of Fig.16 This is a front view of the assembly of the stator core, windings and heat pipe radiator according to an embodiment of the present invention; Fig.17 This is a rear view of the stator core, windings and heat pipe radiator of an embodiment of the present invention after assembly; Fig.18 is a three-dimensional schematic diagram of a fan according to an embodiment of the present invention; Fig.19 A cross-sectional view of a forced air cooling integrated structure of a high power density outer rotor permanent magnet motor according to an embodiment of the present invention; Fig. 20 It is a front view of a forced air cooling integrated structure of a high power density outer rotor permanent magnet motor according to an embodiment of the present invention; Fig.21It is a rear view of the forced air cooling integrated structure of the high power density outer rotor permanent magnet motor according to an embodiment of the present invention; Fig. 22 A cross-sectional view of a forced air cooling integrated structure of a high power density outer rotor permanent magnet motor according to an embodiment of the present invention; Fig.23 A wind speed vector cloud diagram according to an embodiment of the present invention; Fig.24 A wind speed streamline cloud diagram according to an embodiment of the present invention; Fig.25 is a cross-sectional schematic diagram of an embodiment of the present invention; Fig.26 A cross-sectional wind speed distribution cloud diagram of an embodiment of the present invention; Fig. 27 The temperature distribution cloud diagram of the motor of the heat pipe-free cooling device of the embodiment of the present invention, wherein: (a) is the temperature distribution cloud diagram of the whole motor, (b) is the temperature distribution cloud diagram of the stator, (c) is the temperature distribution cloud diagram of the winding, (d) is the temperature distribution cloud diagram of the permanent magnet, and (e) is the temperature distribution cloud diagram of the rotor; Fig.28 The temperature distribution cloud diagram of the motor of the forced air cooling integrated structure of the high power density outer rotor permanent magnet motor using the embodiment of the present invention, wherein (a) is the temperature distribution cloud diagram of the whole motor, (b) is the temperature distribution cloud diagram of the stator, (c) is the temperature distribution cloud diagram of the winding, (d) is the temperature distribution cloud diagram of the permanent magnet, and (e) is the temperature distribution cloud diagram of the rotor; Fig.29 Comparison of motor temperature under different cooling methods.

[0020] Explanation of the reference numerals: 1-flange, 2-lower section of hollow shaft, 3-heat pipe hole, 5-bearing a, 6-sleeve a, 7-end cover a, 8-housing, 9-rotor core, 10-permanent magnet, 11-stator core, 12-winding coil, 13-flat heat pipe, 14-L-type heat pipe, 15-heat sink, 16-bearing b, 17-sleeve b, 18-end cover b, 19-fan blade, 20-connecting key, 21-wind shield, 22-upper section of hollow shaft, 23-rotor Core limiting protrusion, 24-casing limiting protrusion, 25-assembly groove, 26-flange threaded hole, 27-flat heat pipe end, 28-flat heat pipe end, 29-three-phase line reserved hole, 30-spray cooling device, 31-hollow shaft middle section, 32-assembly protrusion, 33-L-type heat pipe groove, 34-flat heat pipe groove, 35-L-type heat pipe end, 36-L-type heat pipe end, 37-epoxy resin, 38-water pipe, 39-water injection pipe. DETAILED DESCRIPTION

[0021] The technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0022] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] The components of the embodiments of the present invention generally described and shown in the drawings herein may be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention.

[0024] The present invention provides the following technical solution: A stator axial segmented high power density outer rotor permanent magnet motor ventilation cooling structure, comprising a hollow shaft, a stator core 11, a winding coil 12, a rotor core 9, a permanent magnet 10, a housing 8, a heat conducting element, a fan and a spray cooling device 30, wherein the stator core 11 is provided with an assembly groove 25, wherein the winding coil 12 is arranged in the winding slot of the stator core 11; wherein the hollow shaft is located on the inner side of the stator core 11, the hollow shaft is provided with a mounting protrusion matching the mounting groove 25, and the hollow shaft is fixedly connected to the stator core 11 through the mounting protrusion; wherein The middle casing 8 is arranged along the circumference of the rotor core 9, the casing 8 is fixedly connected to the outer side of the rotor core 9, and the casing 8 has an end cover b18 and an end cover a7, the casing 8 is rotatably arranged on the hollow shaft through the end cover b18 and the end cover a7, specifically, the rotor core 9 is fixedly arranged on the casing 8 through the casing limiting protrusion 24, the permanent magnet 10 is fixed on the rotor core 9 through the rotor core limiting protrusion 23, and the casing 8 has an end cover b18 and an end cover a7, a shaft sleeve b17 and a bearing b16 are arranged on the end cover b18, a shaft sleeve a6 and a bearing a5 are arranged on the end cover a7, and the casing 8 is rotatably arranged on the hollow shaft 2 through the bearings on the end cover b18 and the end cover a7; wherein the permanent magnet 10 is arranged on the inner side of the rotor core 9; wherein the fan is fixedly arranged on the end cover b18; wherein the heat conducting element is arranged on the stator core 11 and the winding coil 12; wherein the spray cooling device 30 is arranged on the inner side of the hollow shaft. One side of the driving motor of the present invention is installed and fixed by a flange 1 and a hollow shaft. A flange threaded hole 26 is also opened on the flange 1. In order to improve the heat dissipation effect of the cooling structure, a water atomization cooling device 30 is arranged inside the hollow shaft to spray atomized liquid. The atomized liquid water is evenly distributed on the surface of the heat sink. The atomized liquid vaporizes and absorbs heat. After absorbing heat and liquefying per unit time, the atomized liquid takes away more heat, thereby improving the heat dissipation effect. At the same time, the coordinated cooling of the heat-conducting element and the fan makes the overall cooling effect of the device better.

[0025] The permanent magnet 10 of the embodiment of the present invention is bonded and fixed to the inner side of the rotor core 9, wherein the hollow shaft includes a hollow shaft upper section 22, a hollow shaft middle section 31 and a hollow shaft lower section 2, wherein the hollow shaft upper section 22 and the hollow shaft lower section 2 are both provided with an assembly groove 25, wherein the hollow shaft middle section 31 is provided with an assembly protrusion 32 corresponding to the assembly groove 25, and the hollow shaft upper section 22, the hollow shaft middle section 31 and the hollow shaft lower two sections are all fixed by the cooperation of the assembly groove 25 and the assembly protrusion 32. The permanent magnet 10 of the present invention can directly adopt a surface-mounted structure, the installation process is simple and easy to implement, the yoke of the rotor core 9 is thin, which is conducive to reducing the weight of the rotor core 9 and further improving the power density of the motor; in addition, the hollow shaft is segmented, and the hollow shaft is divided into three sections: upper, middle and lower, and the assembly groove 25 and the assembly protrusion 32 are provided, which can more conveniently realize the connection of the heat pipe. This design can not only improve the assembly efficiency of the heat pipe, but also ensure the connection reliability and stability of the heat pipe. At the same time, the segmented processing of the hollow shaft can also reduce the overall length of the hollow shaft, reduce the overall weight of the motor, and improve the operating efficiency and reliability of the motor. In addition, the design of the assembly groove 25 and the assembly protrusion 32 can also increase the strength and rigidity of the hollow shaft, and improve the operating stability and life of the motor.

[0026] The heat conducting element of the embodiment of the present invention is a heat pipe, wherein the heat pipe includes a flat heat pipe 13 and an L-shaped heat pipe 14, wherein the flat heat pipe 13 and the L-shaped heat pipe 14 are both made of aluminum nitride material, wherein the width of the flat heat pipe 13 and the L-shaped heat pipe 14 are both 4-6 mm, and the thickness is both 2-3 mm. The heat pipe of the present invention is made of aluminum nitride material with high hardness, high thermal conductivity and good mechanical properties, and can prevent eddy current loss when connected to the winding coil 12.

[0027] The spray cooling device 30 of the embodiment of the present invention is arranged on the upper section 22 of the hollow shaft, wherein the spray cooling device 30 includes a nozzle, a water pipe 38 and a water injection pipe 39, wherein the water pipe 38 is fixedly arranged along the inner wall of the upper section 22 of the hollow shaft, wherein a plurality of nozzles are arranged, each nozzle is arranged on the water pipe 38, wherein one end of the water injection pipe 39 is connected to the water pipe 38, and the other end of the water injection pipe 39 extends to the outside of the lower section 2 of the hollow shaft and is connected to an external water source.

[0028] The fan of the embodiment of the present invention comprises a loading end cover, a connecting key 20 and a fan blade, wherein the loading end cover is an annular structure, and the loading end cover is fixed on the top surface of the end cover b18; wherein a plurality of fan blades are provided, and the fan blades are provided on the inner side of the loading end cover, and the fan blades are provided at intervals along the circumference of the loading end cover; and the connecting key 20 is fixedly provided at the center of the loading end cover. The present invention adopts a high power density outer rotor permanent magnet motor forced air cooling integrated structure, one side of the driving motor is fixed by a flange 1 and a hollow shaft, and the other side is connected to a loading end cover, one end of the loading end cover is connected to a load, and the other end is connected to a fan blade, and rotates with the motor, realizing forced ventilation cooling of the heat sink in the hollow shaft, reducing the temperature rise of the motor, and no additional fan is required for ventilation cooling, thereby improving the working efficiency of the drive system.

[0029] The flat heat pipe 13 and the L-shaped heat pipe 14 of the embodiment of the present invention are provided in plurality, each of the flat heat pipe 13 has a flat heat pipe heat absorption end 27 and a flat heat pipe heat release end 28, the flat heat pipe heat absorption end 27 is connected to the winding coil 12, wherein the flat heat pipe heat release end 28 extends to the hollow area inside the hollow shaft along the radial direction of the stator core 11; each L-shaped heat pipe 14 has an L-shaped heat pipe heat absorption end 35 and an L-shaped heat pipe heat release end 36, the L-shaped heat pipe heat absorption end 35 is fixedly connected to the yoke of the stator core 11, the L-shaped heat pipe heat release end 36 extends to the hollow area inside the hollow shaft along the radial direction of the stator core 11, each L-shaped heat pipe heat release end 36 and the flat heat pipe heat release end 28 are connected to the heat sink 15, and the hollow shaft is provided with a plurality of L-shaped heat pipe grooves 33 and flat heat pipe grooves 34 spaced apart along the circumferential direction. The flat heat pipe 13 of the present invention is connected to the winding coil 12, and the L-shaped heat pipe is inserted into the yoke of the stator core 11, which can fully conduct heat and achieve a better cooling effect for the entire device.

[0030] The stator core 11 , the winding coil 12 and the heat pipe of the embodiment of the present invention are potted as a whole with epoxy resin 37 .

[0031] The L-shaped heat pipe and the flat heat pipe 13 of the embodiment of the present invention are both fixed to the heat sink 15 by tinning, wherein the heat sink 15 is a circular heat sink, and heat sinks 15 of different structural forms may also be used, for example, a strip heat sink. The heat sink 15 is assembled with the heat release end of the heat pipe, and more heat dissipation area can be increased under the condition of axial blowing. A wind shield 21 is provided at one end of the hollow shaft adjacent to the loading end cover.

[0032] Figure 25 is a vector cloud diagram of the wind speed of the blades of the loading end cap. In this figure, it can be seen that the wind speed near the blades is greater and the effect is better, and the axial wind speed can reach more than 15m / s. Therefore, it can be inferred that the wind speed effect generated by the loading end cap of the present invention is very good.

[0033] Fig.26The wind speed streamline cloud diagram for the loaded end cover shows that the wind speed in the axial direction is large in the wind speed streamline cloud diagram, which can take away more heat. The direction of the lines in the wind speed streamline diagram is the wind direction. It can be seen that the wind speed effect generated by the loaded end cover in this invention patent is good.

[0034] Fig.26 The wind speed streamline cloud diagram for the loaded end cover shows that the wind speed in the axial direction is large in the wind speed streamline cloud diagram, which can take away more heat. The direction of the lines in the wind speed streamline diagram is the wind direction. It can be seen that the wind speed effect generated by the loaded end cover in this invention patent is good.

[0035] Fig. 27 The cross-sectional wind speed distribution cloud diagram shows the effect of the loading end cover in generating axial wind speed. From this, it can be concluded that the loading end cover in this patent invention has a good generating effect.

[0036] Fig.29 This is a temperature distribution cloud diagram of a motor without a heat pipe cooling device. The five figures above show the overall temperature, stator temperature, rotor temperature, winding temperature and permanent magnet temperature of the motor. It can be seen that the temperature distribution of the motor without a heat pipe cooling device is high.

[0037] The present invention makes full use of the advantages of high thermal conductivity of the heat pipe, inserts the heat absorbing end of the heat pipe into the heat generating part of the motor, and extends the heat releasing end of the heat pipe radially along the drive motor to the air area of ​​the motor hollow shaft, and is connected with a heat sink to increase the heat dissipation area. The heat can be efficiently transferred to the external space of the permanent magnet motor through forced ventilation cooling and heat dissipation of the motor self-fan. The proposed cooling structure can effectively reduce the volume, weight and cost of the drive motor, and has great application and economic significance for the cooling system analysis and heat dissipation analysis of high power density permanent magnet motors.

[0038] in Fig.23 This is a vector cloud diagram of the wind speed of the blades with the end cap loaded. In this figure, it can be seen that the wind speed near the blades is higher and the effect is better, and the axial wind speed can reach more than 20m / s. Therefore, it can be inferred that the wind speed effect generated by the end cap of the present invention is very good.

[0039] in Fig.24 , showing the wind speed streamline cloud diagram of the fan blade loaded with the end cover. In the wind speed streamline cloud diagram, the axial wind speed is large, which can take away more heat. The direction of the lines in the wind speed streamline diagram is the wind direction. It can be seen that the wind speed effect generated by the loaded end cover in this invention patent is good.

[0040] in Fig.25 A schematic cross-section of the loading end cap is shown, illustrating the structure of the loading end cap.

[0041] in Fig.26, which is a cross-sectional wind speed distribution cloud diagram, it can be seen that the wind speed reaches more than 10m / s on a certain section in the generated wind path. It can be seen that in this invention patent, loading the end cover can produce a better wind effect.

[0042] in Fig. 27 This is a temperature distribution cloud diagram of a motor without a heat pipe cooling device. The five figures above show the overall temperature, stator temperature, rotor temperature, winding temperature and permanent magnet temperature of the motor. It can be seen that the temperature distribution of the motor without a heat pipe cooling device is high.

[0043] in Fig.28 This is a temperature distribution cloud diagram of a motor without a heat pipe cooling device. The above five figures can show the overall temperature, stator temperature, rotor temperature, winding temperature and permanent magnet temperature of the motor. It can be seen that the temperature distribution of the motor with a heating pipe cooling device is better than that without a heating pipe cooling device, and can reduce more heat, which can reflect the important role of this patent invention.

[0044] in Fig.29 Yes Fig.28 The supplementary explanation shows that the average temperature and the maximum temperature of the heat sink are better than those of the motor structure without the heat sink. At the same time, the motor can be better protected from damage and economic losses caused by over-temperature.

[0045] Obviously, the above-mentioned embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not limitations on the embodiments of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made on the basis of the above description. It is impossible to list all the embodiments here. All obvious changes or modifications derived from the technical solution of the present invention are still within the protection scope of the present invention.

Claims

1. A high power density outer rotor permanent magnet motor ventilation cooling structure, characterized in that: The invention comprises a hollow shaft, a stator core (11), a winding coil (12), a rotor core (9), a permanent magnet (10), a housing (8), a heat conducting element, a fan and a spray cooling device (30). The stator core (11) is provided with a mounting groove (25). The winding coil (12) is arranged in a winding slot of the stator core (11); The hollow shaft is located inside the stator core (11), the hollow shaft is provided with a mounting protrusion matching the assembly groove (25), and the hollow shaft is fixedly connected to the stator core (11) via the mounting protrusion; The housing (8) is arranged along the circumference of the rotor core (9), the housing (8) is fixedly connected to the outer side of the rotor core (9), and the housing (8) has an end cover b (18) and an end cover a (7), and the housing (8) is rotatably arranged on the hollow shaft through the end cover b (18) and the end cover a (7); The permanent magnet (10) is arranged on the inner side of the rotor core (9); the fan is fixedly arranged on the end cover b (18); the heat conducting element is arranged on the stator core (11) and the winding coil (12); and the spray cooling device (30) is arranged on the inner side of the hollow shaft.

2. The high power density outer rotor permanent magnet motor ventilation and cooling structure according to claim 1 is characterized in that: The permanent magnet (10) is bonded and fixed to the inner side of the rotor core (9); the hollow shaft comprises an upper hollow shaft section (22), a middle hollow shaft section (31) and a lower hollow shaft section (2); the upper hollow shaft section (22) and the lower hollow shaft section (2) are both provided with an assembly groove (25); the middle hollow shaft section (31) is provided with an assembly protrusion (32) corresponding to the assembly groove (25); the upper hollow shaft section (22), the middle hollow shaft section (31) and the lower hollow shaft section (2) are all fixed by the cooperation between the assembly groove (25) and the assembly protrusion (32).

3. The high power density outer rotor permanent magnet motor ventilation and cooling structure according to claim 1 is characterized in that: The heat-conducting element is a heat pipe, and the heat pipe comprises a flat heat pipe (13) and an L-shaped heat pipe (14). The flat heat pipe (13) and the L-shaped heat pipe (14) are both made of aluminum nitride material. The width of the flat heat pipe (13) and the L-shaped heat pipe (14) are both 4-6 mm, and the thickness is both 2-3 mm.

4. The high power density outer rotor permanent magnet motor ventilation and cooling structure according to claim 2 is characterized in that: The spray cooling device (30) is arranged on the upper section (22) of the hollow shaft. The spray cooling device (30) comprises a nozzle, a water pipe (38) and a water injection pipe (39). The water pipe (38) is fixedly arranged along the inner wall of the upper section (22) of the hollow shaft. A plurality of nozzles are arranged, and each nozzle is arranged on the water pipe (38). One end of the water injection pipe (39) is connected to the water pipe (38), and the other end of the water injection pipe (39) extends to the outside of the lower section (2) of the hollow shaft and is connected to an external water source.

5. The high power density outer rotor permanent magnet motor ventilation and cooling structure according to claim 1, characterized in that: The fan comprises a loading end cover, a connecting key (20) and a fan blade, wherein the loading end cover is an annular structure and is fixed to the top surface of the end cover b (18); a plurality of fan blades are provided, the fan blades are arranged on the inner side of the loading end cover, and the fan blades are arranged at intervals along the circumference of the loading end cover; and the connecting key (20) is fixedly provided at the center of the loading end cover.

6. The high power density outer rotor permanent magnet motor ventilation cooling structure according to claim 3 is characterized in that: A plurality of the flat heat pipes (13) and L-shaped heat pipes (14) are provided, each of the flat heat pipes (13) having a flat heat pipe heat absorbing end (27) and a flat heat pipe heat releasing end (28), the flat heat pipe heat absorbing end (27) being connected to the winding coil (12), and the flat heat pipe heat releasing end (28) extending along the radial direction of the stator core (11) to the hollow area inside the hollow shaft; each of the L-shaped heat pipes (14) having an L-shaped heat pipe heat absorbing end (35) and an L-shaped heat pipe heat releasing end (36), the L-shaped heat pipe heat absorbing end (35) being fixedly connected to the yoke of the stator core (11), and the L-shaped heat pipe heat releasing end (36) extending along the radial direction of the stator core (11) to the hollow area inside the hollow shaft, and each of the L-shaped heat pipe heat releasing end (36) and the flat heat pipe heat releasing end (28) being connected to a heat sink (15).

7. The high power density outer rotor permanent magnet motor ventilation and cooling structure according to claim 6, characterized in that: The stator core (11), the winding coil (12) and the heat pipe are potted into one body with epoxy resin (37).

8. The high power density outer rotor permanent magnet motor ventilation and cooling structure according to claim 6, characterized in that: The L-shaped heat pipe and the flat heat pipe (13) are both fixed to the heat sink (15) by spot tinning, and a windshield (21) is provided at one end of the hollow shaft adjacent to the loading end cover.

Images