CN117879257A - Motor air cooling system - Google Patents

Abstract

The invention relates to the technical field of motor cooling, in particular to a motor air cooling system, which aims to solve the problems of low cooling efficiency, insufficient reliability and high manufacturing and using costs of the existing motor cooling system for a low-rotation-speed motor. The invention comprises a motor rotating shaft, a fan and a transmission wheel set; the transmission wheel set comprises an inner transmission wheel and an outer transmission wheel, the inner transmission wheel and the outer transmission wheel are coaxially arranged, the inner transmission wheel is sleeved on and connected with a motor rotating shaft, and the outer transmission wheel is connected with a fan; the inner driving wheel is driven by the motor rotating shaft to rotate so as to drive the outer driving wheel to rotate, and the outer driving wheel drives the fan to rotate so that the rotating speed of the fan is higher than that of the motor rotating shaft. The motor rotating shaft of the low-rotation-speed motor drives the fan to rotate at a high speed through the transmission wheel set, so that the fan generates enough air quantity and air pressure to radiate heat of the heating component, the cooling efficiency is improved, a new mechanism is not introduced, the running reliability is improved, and the manufacturing and using cost of the motor is reduced.

Description

Motor air cooling system

Technical Field

The invention relates to the technical field of motor cooling, in particular to a motor air cooling system.

Background

The air cooling motor is widely applied to the fields of new energy power generation, ship propulsion, ore exploitation and the like by virtue of the characteristics of simple structure, low maintenance cost, reliable operation and the like. The common air cooling structure of the motor mainly comprises a fan impeller arranged at the extending end of a rotating shaft, wherein air flow is formed after the fan impeller rotates and is boosted, and air flow in or around the motor is promoted, so that the effect of cooling the motor is achieved. Along with the continuous increase of motor power, the heat dissipation requirement further improves, and the coaxial fan rotational speed of low rotational speed motor is lower, and wind pressure and the amount of wind that fan impeller produced are all lower, lead to cooling system circulation amount of wind little, wind speed low, and cooling efficiency also reduces, is difficult to satisfy the heat dissipation demand of motor, has brought safe risk to the long-term safe and reliable operation of motor.

The cooling efficiency of the low-rotation-speed motor can be effectively improved by adopting liquid cooling modes such as water cooling, oil cooling and the like, but the structure of the liquid cooling system is complex compared with that of an air cooling system, the operation reliability is low, and the leakage risk exists. The variable speed transmission mechanism or an air cooling mode of an external motor driving fan is adopted, so that higher impeller rotating speed can be obtained, and the cooling efficiency of the motor is improved. The introduction of new devices and structural components will result in an increased volume of the motor and reduced operational reliability, as well as increased cost of the motor. In summary, the existing motor cooling system has the problems of low cooling efficiency, insufficient reliability and high manufacturing and using costs for low-rotation-speed motors.

Disclosure of Invention

The invention aims to provide a motor air cooling system so as to solve the problems of low cooling efficiency, insufficient reliability and high manufacturing and using costs of the existing motor cooling system for a low-rotation-speed motor.

In order to solve the technical problems, the technical scheme provided by the invention is as follows:

a motor air cooling system comprises a motor rotating shaft, a fan and a transmission wheel set;

the transmission wheel set comprises an inner transmission wheel and an outer transmission wheel, the inner transmission wheel and the outer transmission wheel are coaxially arranged, the inner transmission wheel is sleeved on the motor rotating shaft and connected with the motor rotating shaft, and the outer transmission wheel is connected with the fan;

the inner driving wheel is driven by the motor rotating shaft to rotate so as to drive the outer driving wheel to rotate, and then the outer driving wheel drives the fan to rotate so that the rotating speed of the fan is higher than that of the motor rotating shaft.

Further, the inner driving wheel comprises a first magnet and a first ring body, and the first magnet is arranged on the first ring body; the plurality of first magnets are uniformly distributed around the axis of the first ring body;

the outer driving wheel comprises a second magnet and a second ring body, and the second magnet is arranged on the second ring body; the second magnets are uniformly distributed around the axis of the second ring body.

Further, the number of the first magnets is larger than the number of the second magnets, and the rotation speed ratio of the inner driving wheel to the outer driving wheel is equal to the ratio of the number of the second magnets to the number of the first magnets.

Further, the magnetic poles of the first magnet are distributed along the radial direction of the first ring body, and the magnetic poles of the second magnet are distributed along the radial direction of the second ring body; the magnetic pole directions of the adjacent first magnets are opposite, and the magnetic pole directions of the adjacent second magnets are opposite.

Further, the transmission wheel set further comprises a magnetic adjusting ring, and the magnetic adjusting ring is sleeved on the inner transmission wheel and is arranged between the inner transmission wheel and the outer transmission wheel; the magnetic adjusting ring comprises ferromagnetic materials and nonferromagnetic materials which are arranged at intervals.

Further, the motor air cooling system further comprises a shell, a rotor core and a stator core, wherein the rotor core and the stator core are arranged in the shell, and the rotor core is inserted into the stator core;

the rotor core, the stator core, the fan and the casing form a first circulation path; the first circulating passage comprises an air inlet channel, the fan, an axial ventilation channel, a radial ventilation channel, a converging channel and a return air channel which are sequentially communicated;

the air inlet channel is arranged at one air inlet end of the fan and is communicated with the air inlet of the shell; the rotor core is provided with the axial ventilation channel extending along the axis direction of the rotor core; the radial ventilation passage extends in a radial direction of the rotor core and the stator core and passes through the rotor core and the stator core; a gap extending along the axial direction of the stator core between the casing and the stator core forms the confluence channel; the return air channel is communicated with an air outlet on the shell so as to discharge air out of the shell.

Further, the radial ventilation channels include a rotor radial channel and a stator radial channel;

the rotor core is divided into a plurality of sections along the axis direction of the rotor core, and gaps among the sections form the radial passage of the rotor;

the stator core is divided into a plurality of sections along the axis direction of the stator core, and gaps among the sections form the radial channels of the stator.

Further, the rotor core, the stator core, the fan, and the casing form a second circulation path; the second circulation passage comprises an air inlet channel, the fan, the axial ventilation channel, an end face ventilation channel, the converging channel and the return air channel which are sequentially communicated;

the end face ventilation channel is formed by the end, far away from the air inlet channel, of the stator core and the rotor core and the shell.

Further, the motor air cooling system further comprises a wind shield, wherein the wind shield is connected with the shell and used for separating the return air channel and the rotor radial channel.

Further, the motor air cooling system also comprises a heat exchanger; the heat exchanger is communicated with the air outlet and the air inlet of the shell;

under the drive of the fan, air flows along the first circulating passage and the second circulating passage; air in the heat exchanger enters the air inlet channel from the air inlet of the shell and returns to the heat exchanger from the air outlet of the shell through the air return channel.

In summary, the technical effects achieved by the invention are as follows:

the motor air cooling system provided by the invention comprises a motor rotating shaft, a fan and a transmission wheel set; the transmission wheel set comprises an inner transmission wheel and an outer transmission wheel, the inner transmission wheel and the outer transmission wheel are coaxially arranged, the inner transmission wheel is sleeved on and connected with a motor rotating shaft, and the outer transmission wheel is connected with a fan; the inner driving wheel is driven by the motor rotating shaft to rotate so as to drive the outer driving wheel to rotate, and the outer driving wheel drives the fan to rotate so that the rotating speed of the fan is higher than that of the motor rotating shaft.

According to the motor air cooling system provided by the invention, the motor rotating shaft of the low-rotation-speed motor drives the fan to rotate at a high speed through the transmission wheel set, so that the fan generates enough air quantity and air pressure to radiate heat of the heating component, the cooling efficiency is improved, and the long-term safe and reliable operation of the motor is ensured. Meanwhile, a new mechanism is not introduced, the motor is not increased in size and complex in structure, the running reliability is further guaranteed, an additional power driving fan is not needed, and the manufacturing and using cost of the motor is reduced.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are needed in the description of the embodiments or the prior art will be briefly described, and it is obvious that the drawings in the description below are some embodiments of the present invention, and other drawings can be obtained according to the drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic structural diagram of an air cooling system of a motor according to an embodiment of the present invention;

FIG. 2 is a schematic view of a rotor and stator structure;

FIG. 3 is a schematic diagram of a drive train;

FIG. 4 is a schematic structural view of an electrically excited rotor;

fig. 5 is a schematic structural view of a permanent magnet excited rotor.

Icon: 100-a motor rotating shaft; 200-fans; 300-transmission wheel sets; 400-a shell; 500-rotor core; 600-stator core; 700-wind deflector; 800-heat exchanger; 900-stator windings; 1000-rotor windings; 1100-magnetic steel; 310-an inner driving wheel; 320-outer drive wheel; 330-adjusting magnetic rings; 311-first magnet; 312-a first ring body; 321-a second magnet; 322-a second ring body; 910-stator left end winding; 920-stator slot windings; 930-stator right end winding; 101-an air inlet channel; 102-axial ventilation channels; 103-radial ventilation channels; 104-confluence channel; 105-return air channel; 201-end face ventilation channels.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments of the present invention. The components of the embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the invention, as presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

Some embodiments of the present invention are described in detail below with reference to the accompanying drawings. The following embodiments and features of the embodiments may be combined with each other without conflict.

The existing motor cooling system has the problems of low cooling efficiency, insufficient reliability and high manufacturing and using cost for a low-rotation-speed motor.

In view of this, the present invention provides a motor air cooling system provided by the present invention, which includes a motor shaft 100, a fan 200 and a driving wheel set 300; the transmission wheel set 300 comprises an inner transmission wheel 310 and an outer transmission wheel 320, wherein the inner transmission wheel 310 and the outer transmission wheel 320 are coaxially arranged, the inner transmission wheel 310 is sleeved on the motor rotating shaft 100 and is connected with the motor rotating shaft 100, and the outer transmission wheel 320 is connected with the fan 200; the inner driving wheel 310 rotates under the driving of the motor rotating shaft 100 to drive the outer driving wheel 320 to rotate, and the outer driving wheel 320 drives the fan 200 to rotate so that the rotating speed of the fan 200 is higher than that of the motor rotating shaft 100.

According to the motor air cooling system provided by the invention, the motor rotating shaft 100 of the low-rotation-speed motor drives the fan 200 to rotate at a high speed through the transmission wheel set 300, so that the fan 200 generates enough air quantity and air pressure to radiate heat of heating components, the cooling efficiency is improved, and the long-term safe and reliable operation of the motor is ensured. Meanwhile, no new mechanism is introduced, the motor is not increased in size and complex in structure, the running reliability is further guaranteed, the fan 200 is not required to be driven by additional power, and the manufacturing and using cost of the motor is reduced.

The structure and shape of the motor air cooling system provided in this embodiment are described in detail below with reference to fig. 1 to 5:

the motor air cooling system provided in this embodiment includes a motor shaft 100, a fan 200, a driving wheel set 300, a casing 400, a rotor core 500, a stator core 600, a wind shield 700, a heat exchanger 800, a stator winding 900 and a rotor winding 1000, as shown in fig. 1, and forms a first circulation path and a second circulation path.

Specifically, the motor shaft 100 drives the fan 200 to work through the driving wheel set 300, the rotor core 500 and the rotor winding 1000 form a rotor, and the stator core 600 and the stator winding 900 form a stator, as shown in fig. 2; the rotor core 500 is sleeved on the motor rotating shaft 100 and connected with the motor rotating shaft 100, and the rotor is inserted on the stator; the wind deflector 700 is mounted to the cabinet 400.

The first circulation path includes an air inlet channel 101, a fan 200, an axial ventilation channel 102, a radial ventilation channel 103, a converging channel 104, an air return channel 105 and a heat exchanger 800 which are sequentially communicated, as shown in fig. 1, the air inlet channel 101 is arranged at one air inlet end of the fan 200 and is communicated with an air inlet of the casing 400, that is, one end of the air inlet channel 101 is communicated with the air inlet of the casing 400, and the other end is communicated with an air inlet end of the fan 200; the rotor core 500 is provided with an axial ventilation passage 102 extending in the direction of its own axis; radial ventilation channels 103 extend in a radial direction of rotor core 500 and stator core 600 and pass through rotor core 500 and stator core 600; a gap between the case 400 and the stator core 600 extending in the axial direction of the stator core 600 forms a bus duct 104; the return air channel 105 communicates with an air outlet on the housing 400 to expel air out of the housing 400 and into the heat exchanger 800, an outlet of the heat exchanger 800 communicates with an air inlet of the housing 400, and an inlet of the heat exchanger 800 communicates with an air outlet of the housing 400. The heat exchanger 800 is installed in the casing 400, cools down in order to guarantee the cooling effect to the air through the heat exchanger 800, guarantees simultaneously that form airtight passageway and avoid impurity to get into inside the motor, guarantees the safe and stable operation of motor.

In this embodiment, the wind guard 700 is used to separate the return air channel 105 and the radial rotor channel to ensure smooth air circulation, so that air in the return air channel 105 flows into the heat exchanger 800 through the air outlet of the housing 400, and air flow confusion caused by that air in the return air channel 105 enters the radial rotor channel without cooling is avoided, thereby reducing cooling efficiency. I.e., the circulation path is ensured to flow unidirectionally by the wind deflector 700 to ensure the cooling effect.

In this embodiment, the second circulation path includes an air inlet channel 101, a fan 200, an axial ventilation channel 102, an end face ventilation channel 201, a confluence channel 104 and an air return channel 105 that are sequentially communicated; the end surfaces of the stator core 600 and the rotor core 500 away from the air inlet passage 101 and the casing 400 form an end surface ventilation passage 201. That is, the first circulation path is shared with other paths of the second circulation path except for the radial ventilation path 103 and the end ventilation path 201, while air of the end ventilation path 201 flows in the radial direction of the rotor core 500.

In this embodiment, the radial ventilation channels 103 include a rotor radial channel and a stator radial channel. Specifically, the rotor core 500 is divided into a plurality of segments in the direction of its own axis, and gaps between the segments form rotor radial passages, as shown in fig. 4 and 5; the stator core 600 is divided into a plurality of stages along the axial direction thereof, and gaps between the stages form radial passages of the stator, so that air can be fully contacted with the heat generating components, and the cooling effect is improved.

The motor air cooling system provided in this embodiment drives the fan 200 to operate by the motor rotating shaft 100 through the driving wheel set 300, and enables the fan 200 to obtain a higher rotating speed, so that the fan 200 generates enough wind pressure and wind quantity to cool the heating component. And simultaneously, the first circulating passage and the second circulating passage are combined to enable the air to be fully contacted with the heating component and fully matched with the fan 200, so that reliable and efficient cooling is performed. In addition, since the radial ventilation channels 103 flow along the radial direction of the rotor core 500, when air enters the converging channel 104 through the radial ventilation channels 103, the air is blocked by the inner wall of the casing 400 and flows towards both ends of the converging channel 104, and does not flow only towards the return air channel 105, so that air flow is disordered, non-unidirectional flow of the air is caused, efficient and stable circulation of the air is affected, heat cannot be taken away in time, and cooling effect is reduced; the end face ventilation channel 201 in the second circulation channel solves the problem, air flows along the end face ventilation channel 201 and enters the converging channel 104 under the guidance of the inner wall of the casing 400, and then the air flowing out of the radial ventilation channel 103 is carried into the return air channel 105, so that the unidirectional flow of the air is ensured, the air is stably and smoothly circulated, and the cooling effect is improved. That is, the cooperation of the first circulation passage and the second circulation passage ensures that air circulates stably and smoothly under the driving of the fan 200, and ensures the stability and reliability of the cooling effect.

In this embodiment, the stator winding 900 is axially divided into a stator left end winding 910, a stator slot inner winding 920, and a stator right end winding 930, as shown in fig. 2.

In this embodiment, the rotor may be provided in an electrically excited or permanent magnet excited structure, as shown in fig. 4, and the electrically excited rotor includes a rotor core 500 and a rotor winding 1000, and the permanent magnet excited rotor includes a rotor core 500 and a magnetic steel 1100, as shown in fig. 5.

In this embodiment, the blower 200 includes an intake pipe, an impeller, and an exhaust pipe. When the impeller rotates at a high speed, cold air enters the fan 200 through the air inlet pipe, the cold air rotates along with the fan 200, is thrown into the diffuser under the centrifugal action of the impeller, continuously compressed, flows out of the exhaust pipe at a high flow rate, and flows into the rotor core 500 through the exhaust pipe.

In an alternative to this embodiment, the drive wheel set 300 includes an inner drive wheel 310, an outer drive wheel 320, and a magnetic adjustment ring 330, as shown in fig. 3. The inner driving wheel 310, the magnetic adjusting ring 330 and the outer driving wheel 320 are coaxially arranged, the inner driving wheel 310 is sleeved on the motor rotating shaft 100 and is connected with the motor rotating shaft 100, the magnetic adjusting ring 330 is sleeved on the inner driving wheel 310, and the outer driving wheel 320 is sleeved on the magnetic adjusting ring 330 and is connected with an impeller of the fan 200.

Specifically, the inner driving wheel 310 includes a first magnet 311 and a first ring body 312, the first magnet 311 is mounted on the first ring body 312, and a plurality of first magnets 311 are uniformly distributed around the axis of the first ring body 312 to form a magnetic ring; the outer driving wheel 320 includes a second magnet 321 and a second ring 322, and the second magnet 321 is mounted on the second ring 322; the plurality of second magnets 321 are uniformly distributed around the axis of the second ring body 322 to form a magnetic ring. The magnetic poles of the first magnet 311 are distributed along the radial direction of the first ring body 312, and the magnetic poles of the second magnet 321 are distributed along the radial direction of the second ring body 322; the magnetic pole directions of the adjacent first magnets 311 are opposite, and the magnetic pole directions of the adjacent second magnets 321 are opposite, so that the inner driving wheel 310 drives the outer driving wheel 320 to rotate through the continuously changing magnetic field.

In this embodiment, the ratio of the rotational speed of the inner driving wheel 310 to the rotational speed of the outer driving wheel 320 is equal to the ratio of the number of the second magnets 321 to the number of the first magnets 311, and the number of the first magnets 311 is greater than the number of the second magnets 321 to ensure the effect of increasing the rotational speed of the blower 200. The inner driving wheel 310 rotates under the driving of the motor rotating shaft 100 to drive the outer driving wheel 320 to rotate, and the outer driving wheel 320 drives the fan 200 to rotate, so that the rotating speed of the fan 200 is higher than that of the motor rotating shaft 100.

In this embodiment, the magnetic adjusting ring 330 does not rotate, and is made of ferromagnetic material and nonferromagnetic material arranged at intervals to conduct magnetic conduction, so that stable moment is generated between the inner driving wheel 310 and the outer driving wheel 320, and the inner driving wheel 310 is guaranteed to drive the outer driving wheel 320 to rotate. When the inner driving wheel 310 rotates, the generated magnetic field rotates, and the outer driving wheel 320 is driven to rotate at a higher speed under the action of magnetic force.

The air flows along the first circulation path and the second circulation path under the driving of the blower 200; air in the heat exchanger 800 enters the air inlet channel 101 from the air inlet of the housing 400 and returns to the heat exchanger 800 from the air outlet of the housing 400 through the air return channel 105

In an alternative of this embodiment, the driving wheel set 300 may be provided as gears, the driving wheel is sleeved on the motor rotating shaft 100 and connected with the motor rotating shaft 100, and the driven wheel is connected with the fan 200, and since the fan 200 is coaxially arranged with the motor rotating shaft 100, at least one set of gears is required for torque transmission and speed change. The group of gears comprises a first gear and a second gear which are coaxially arranged and have the same rotating speed, namely, the first gear and the second gear are fixedly connected through a shaft. The driven wheel drives the first gear, and the second gear drives the fan 200 to rotate. In contrast, the structure has the advantages of more parts, complex transmission, large occupied space and poor integration level, needs lubrication, has high manufacturing, using and maintaining costs, can realize non-contact transmission in a magnetic connection mode, does not need lubrication, and has simple structure and small occupied space.

The working process of the motor air cooling system provided by the embodiment is as follows:

a first circulation path: under the drive of the fan 200, cold air enters the air inlet channel 101 from the heat exchanger 800 through the air inlet of the shell 400, after passing through the fan 200, the cold air enters the axial ventilation channel 102 and flows along the radial ventilation channel 103, firstly passes through the radial rotor channel and then passes through the radial stator channel, and the cold air performs convection heat exchange with the stator core 600, the stator slot inner winding 920, the rotor core 500 and the rotor winding 1000, so that heat is taken away, and then flows into the converging ventilation channel; finally, the air flows to the left end winding 910 of the stator, flows to the heat exchanger 800 through the air outlet of the casing 400 for cooling, and is converted into cold air again to participate in the next round of circulation.

A second circulation path: on the basis of the first circulation path, after the cool air enters the axial ventilation passage 102, it flows to the end surface ventilation passage 201 in the direction from the stator left end winding 910 to the stator right end winding 930, and enters the confluence passage 104 to merge with the air flowing out of the radial ventilation passage 103 under the guidance of wind pressure and the inner wall of the casing 400, and then enters the return air passage 105. The second circulation path may cool the rotor core 500 and cool the rotor winding 1000, the stator left end winding 910, and the stator right end winding 930.

Namely, after entering the axial ventilation channel 102, the cold air flows along the radial direction and the axial direction to enter the radial ventilation channel 103 and the end face ventilation channel 201, so that two circulation is realized, the air flow in the end face ventilation channel 201 ensures the unidirectional flow of the air flow in the converging channel 104, the air flowing into the converging channel 104 from the radial ventilation channel 103 is prevented from flowing towards the left end winding 910 and the right end winding 930 of the stator at the same time, the smooth and efficient operation of the two circulation is ensured, and particularly, the cooling effect of the first circulation channel is improved. The high speed operation of the blower 200 provides sufficient wind pressure and wind volume to support two cycles of operation, providing a guarantee for cooling the low speed motor.

The motor air cooling system provided by the embodiment realizes that the motor rotating shaft 100 of the low-rotating-speed motor drives the fan 200 to rotate at a high speed through the transmission wheel assembly 300, so that sufficient air quantity and air pressure are ensured to perform cooling circulation, the first circulation passage and the second circulation passage enable cold air to be in full contact with the heating component to perform heat convection so as to take away heat, and meanwhile, the second circulation passage ensures that air in the first circulation passage flows unidirectionally, stably and smoothly, and air circulation efficiency and cooling effect are ensured. The motor air cooling system provided by the embodiment has the advantages of high cooling efficiency, small volume, high integration level, simple structure, low manufacturing and using cost and reliable operation, provides a guarantee for cooling a high-power low-rotation-speed motor, and ensures long-term safe and reliable operation of the motor.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the invention.

Claims (10)

1. The motor air cooling system is characterized by comprising a motor rotating shaft (100), a fan (200) and a transmission wheel set (300);

the transmission wheel set (300) comprises an inner transmission wheel (310) and an outer transmission wheel (320), the inner transmission wheel (310) and the outer transmission wheel (320) are coaxially arranged, the inner transmission wheel (310) is sleeved on the motor rotating shaft (100) and connected with the motor rotating shaft (100), and the outer transmission wheel (320) is connected with the fan (200);

the inner driving wheel (310) is driven by the motor rotating shaft (100) to rotate so as to drive the outer driving wheel (320) to rotate, and then the outer driving wheel (320) drives the fan (200) to rotate so that the rotating speed of the fan (200) is higher than that of the motor rotating shaft (100).

2. The motor air cooling system according to claim 1, wherein the inner driving wheel (310) comprises a first magnet (311) and a first ring body (312), and the first magnet (311) is mounted on the first ring body (312); a plurality of first magnets (311) are uniformly distributed around the axis of the first ring body (312);

the outer transmission wheel (320) comprises a second magnet (321) and a second ring body (322), wherein the second magnet (321) is installed on the second ring body (322); the second magnets (321) are uniformly distributed around the axis of the second ring body (322).

3. The motor air cooling system according to claim 2, wherein the number of the first magnets (311) is larger than the number of the second magnets (321), and a rotation speed ratio of the inner transmission wheel (310) to the outer transmission wheel (320) is equal to a ratio of the number of the second magnets (321) to the number of the first magnets (311).

4. The motor air cooling system according to claim 2, wherein the magnetic poles of the first magnet (311) are distributed along the radial direction of the first ring body (312), and the magnetic poles of the second magnet (321) are distributed along the radial direction of the second ring body (322); the magnetic pole directions of the adjacent first magnets (311) are opposite, and the magnetic pole directions of the adjacent second magnets (321) are opposite.

5. The motor air cooling system according to claim 2, wherein the transmission wheel set (300) further comprises a magnetic modulation ring (330), and the magnetic modulation ring (330) is sleeved on the inner transmission wheel (310) and is arranged between the inner transmission wheel (310) and the outer transmission wheel (320); the magnetic tuning ring (330) comprises a ferromagnetic material and a non-ferromagnetic material which are arranged at intervals.

6. The motor air cooling system according to claim 1, further comprising a casing (400), and a rotor core (500) and a stator core (600) disposed in the casing (400), wherein the rotor core (500) is inserted into the stator core (600);

the rotor core (500), the stator core (600), the fan (200), and the casing (400) form a first circulation path; the first circulation passage comprises an air inlet passage (101), the fan (200), an axial ventilation passage (102), a radial ventilation passage (103), a converging passage (104) and a return air passage (105) which are communicated in sequence;

the air inlet channel (101) is arranged at one air inlet end of the fan (200) and is communicated with an air inlet of the shell (400); the rotor core (500) is provided with the axial ventilation channel (102) extending along the axial direction of the rotor core; the radial ventilation passage (103) extends in a radial direction of the rotor core (500) and the stator core (600) and passes through the rotor core (500) and the stator core (600); a gap extending in an axial direction of the stator core (600) between the housing (400) and the stator core (600) forms the bus duct (104); the return air channel (105) communicates with an air outlet on the housing (400) to expel air out of the housing (400).

7. The electric motor air cooling system according to claim 6, characterized in that the radial ventilation channels (103) comprise a rotor radial channel and a stator radial channel;

the rotor core (500) is divided into a plurality of sections along the axis direction of the rotor core, and gaps among the sections form the radial channels of the rotor;

the stator core (600) is divided into a plurality of sections along the axial direction thereof, and gaps between the sections form the stator radial passages.

8. The motor air cooling system according to claim 7, wherein the rotor core (500), the stator core (600), the blower (200), and the casing (400) form a second circulation path; the second circulation passage comprises an air inlet passage (101), a fan (200), an axial ventilation passage (102), an end face ventilation passage (201), a confluence passage (104) and a return air passage (105) which are sequentially communicated;

the end face ventilation channel (201) is formed by the stator core (600) and one end, far away from the air inlet channel (101), of the rotor core (500) and the machine shell (400).

9. The motor air cooling system of claim 8, further comprising a wind deflector (700), the wind deflector (700) being coupled to the housing (400) for separating the return air duct (105) and the rotor radial duct.

10. The electric motor air cooling system of claim 9, further comprising a heat exchanger (800); the heat exchanger (800) is communicated with an air outlet and an air inlet of the shell (400);

air flows along the first circulation path and the second circulation path under the drive of the fan (200); air in the heat exchanger (800) enters the air inlet channel (101) from an air inlet of the shell (400) and returns to the heat exchanger (800) from an air outlet of the shell (400) through the return air channel (105).