Internal circulation cooling brushless motor for industrial axial flow fan

Abstract

The invention relates to an internal circulation cooling brushless motor for an industrial axial flow fan, which is characterized in that an outer heat dissipation cavity, an inner heat dissipation cavity, a front circulation flow channel, a rear circulation flow channel and an impeller are arranged in the motor, so that a cooling medium in the motor circularly flows; an industrial axial flow fan is arranged in the cylinder, so that airflow driven by the industrial axial flow fan during working flows through the outer wall of the cylinder, the outer wall of the cylinder is quickly cooled, the temperature of a cooling medium is further quickly reduced, and the inner side of a stator assembly is cooled when the cooling medium circularly enters an inner heat dissipation cavity; therefore, the problem that the interior of the motor is polluted due to the fact that the pollutants are brought into the motor by the external refrigerant can be effectively avoided, and the motor can safely and stably work in an environment with relatively high pollutant concentration and fully exert the kinetic energy of the motor.

Description

Technical Field

[0001] The invention belongs to the technical field of motors, and in particular relates to an internal circulation cooling brushless motor for an industrial axial flow fan. Background Art

[0002] Industrial axial fans work in a harsh environment with high concentrations of pollutants (including but not limited to: oil smoke, dust, and water vapor) in the environment, which is not friendly to the motor that drives the fan. When the motor is cooled, pollutants in the external air will be sucked into the motor, causing internal pollution of the motor and affecting the service life of the motor. If a thicker filter layer is set, the cooling effect is reduced, resulting in serious heating of the motor. In order to overcome this problem, the technical solution usually adopted is to reduce the motor power and speed, and reduce the heating of the motor by downshifting, but this method cannot give full play to the efficiency of the motor.

[0003] There are currently some water-cooled motors that can cool the motor with water, thereby greatly reducing the operating temperature of the motor, allowing users to increase the motor speed and give full play to the kinetic energy of the motor. However, the commonly used water-cooled motors currently need to be connected to an external circulating water circuit. This type of motor is more convenient to use in water-related fields, but when used in the field of industrial axial fans, it will cause high costs due to the setting of a circulating water circuit, so it is more cost-effective to use it by downshifting. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide an internal circulation cooling brushless motor for an industrial axial flow fan, so as to solve the technical problem that the traditional brushless motor needs to use external refrigerant when cooling, which causes the external refrigerant to bring pollutants into the motor and cause internal pollution of the motor.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: an internal circulation cooling brushless motor for an industrial axial flow fan, comprising a shell, a stator assembly fixedly arranged in the shell, and a rotor assembly rotatably connected in the shell and coaxially arranged with the stator assembly, one end of the rotating shaft of the rotor assembly extends out of the shell, and the shell comprises a front cover, a cylinder and a rear seat connected in sequence; a rear bearing assembly hole is provided on the front end surface of the rear seat, and a center sleeve extending to the front cover is coaxially arranged on the periphery of the rear bearing assembly hole, the inner diameter of the center sleeve is larger than the outer diameter of the rotor core, the outer edge of the rear seat is connected to the rear end of the cylinder, and the rotor assembly is arranged in the center sleeve; a front bearing assembly hole and an axial hole that are connected to each other are provided on the front cover, the front bearing assembly hole and the axial hole are coaxial, and the axial hole is located at the front part of the front cover, and an outer sleeve extending to the rear seat is provided on the front cover, the outer sleeve is coaxial with the axial hole, and the outer edge of the front cover is connected to the front end of the cylinder; the center sleeve is inserted into the outer sleeve, and the center sleeve The front end of the cylinder is sealed and connected with the front cover, the rear end of the outer sleeve is sealed and connected with the rear seat, an annular mounting cavity is formed between the center sleeve and the outer sleeve, and the stator assembly is installed in the annular mounting cavity; the cylinder body is sleeved on the outside of the outer sleeve and forms an outer heat dissipation cavity with the outer sleeve, and an annular inner heat dissipation cavity is formed between the center sleeve and the rotor assembly, a plurality of rear circulation flow channels connecting the inner heat dissipation cavity and the outer heat dissipation cavity are arranged in the rear seat, a plurality of front circulation flow channels connecting the inner heat dissipation cavity and the outer heat dissipation cavity are arranged in the front cover, and an impeller is connected to the rotating shaft of the rotor assembly, and the impeller is located in the inner heat dissipation cavity; the cylinder body includes a coaxially arranged front ring, a rear ring, a cylinder body formed by winding a corrugated plate, and a head for connecting the end of the cylinder body with the front ring and the rear ring, the inner and outer walls of the cylinder body are respectively circumferentially evenly distributed with a large number of grooves extending along the axial direction thereof, the outer diameters of the front ring and the rear ring are equal to the outer diameters of the rear seat and the front cover, and the bottom of the groove on the outside of the cylinder body is flush with the outer circumferential surface of the front ring or the rear ring.

[0006] As a preferred solution, the outer edge of the front end of the rear seat radially shrinks inwardly to form a first annular step, the rear ring is fixedly welded to the outer edge of the first annular step, an annular confluence groove is formed between the circumferential surface of the rear ring and the first annular step, one end of each of the rear circulation flow channels is circumferentially evenly distributed on the circumferential surface of the first annular step and is connected to the annular confluence groove, the other end of each of the rear circulation flow channels extends to the periphery of the rear bearing assembly hole and is evenly distributed along the circumferential direction, the front end of the circumferential surface of the first annular step radially shrinks inwardly to form a second annular step, the outer sleeve is docked with the second annular step, and the circumferential surface of the second annular step radially shrinks to form a first sealing groove, a first sealing ring is embedded in the first sealing groove, and the first sealing ring abuts against the inner wall of the outer sleeve to achieve sealing.

[0007] As a preferred solution, the outer edge of the front cover is provided with a third annular step facing the rear seat, the outer circumferential surface of the third annular step is the outer wall of the outer sleeve, a second annular sealing groove is coaxially opened on the platform surface of the third annular step, a second sealing ring is arranged inside the second sealing groove, and a convex ring cooperating with the second sealing groove is arranged on the front end surface of the front ring, the convex ring is inserted into the second sealing groove and sealingly abuts against the second sealing ring; one end of each of the front circulation flow channels is circumferentially uniformly distributed on the circumferential surface of the third annular step, and the other end of each of the front circulation flow channels extends to the periphery of the front bearing assembly hole and is uniformly distributed along the circumferential direction.

[0008] As a preferred solution, the sum of the flow areas of all the rear circulation flow channels is greater than the sum of the flow areas of all the front circulation flow channels.

[0009] As a preferred solution, the rotating shaft is sealed and connected to the shaft hole via a sealing ring, and the rotating shaft can rotate relative to the sealing ring.

[0010] As a preferred solution, the impeller is arranged between the rotor core and the rear seat.

[0011] As a preferred solution, both the outer heat dissipation cavity and the inner heat dissipation cavity are filled with heat transfer oil.

[0012] As a preferred solution, the rear bearing assembly hole is a blind hole.

[0013] As a preferred solution, a large number of heat dissipation fins extending axially along the outer sleeve are evenly distributed in the circumference of the outer heat dissipation cavity, each heat dissipation fin is welded to the barrel of the barrel, and each heat dissipation fin is arranged in a groove on the inner wall of the barrel, and both ends of each heat dissipation fin are respectively welded to two heads, and the end of the heat dissipation fin away from the inner wall of the barrel abuts against the outer sleeve.

[0014] The beneficial effects of the present invention are as follows: the present invention arranges an external heat dissipation cavity, an internal heat dissipation cavity, a front circulation flow channel, a rear circulation flow channel and an impeller in the motor, so that the cooling medium inside the motor circulates, and at the same time utilizes the special structure of the cylinder to make the airflow driven by the industrial axial flow fan flow through the outer wall of the cylinder when it is working, quickly cools the outer wall of the cylinder, and then quickly reduces the temperature of the cooling medium, so that when the cooling medium circulates into the internal heat dissipation cavity, the inside of the stator assembly is cooled. Since the motor cooling process does not require the introduction of external refrigerant, it can effectively avoid the problem of external refrigerant bringing pollutants into the motor and causing the inside of the motor to be polluted, thereby ensuring that the motor can work safely and stably in an environment with a large pollutant concentration and give full play to its kinetic energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The specific embodiments of the present invention are further described in detail below with reference to the accompanying drawings, wherein: Figure 1It is a half-section schematic diagram of a specific structure of the internal circulation cooling brushless motor for the industrial axial flow fan of the present invention; Figure 2 is a schematic diagram of a half-section structure of the rear seat of the present invention; Figure 3 is a schematic diagram of a half-section structure of the front cover of the present invention; Figure 4 It is a schematic diagram of the three-dimensional structure of the cylinder of the present invention; Figure 1~Figure 4 In: 1. Shell; 101. Front cover; 102. Cylinder; 102a. Front ring; 102b. Rear ring; 102c. Cylinder body; 102d. End cap; 103. Rear seat; 2. Stator assembly; 3. Rotor assembly; 301. Rotor core; 302. Rotating shaft; 4. Rear bearing assembly hole; 5. Center sleeve; 6. Front bearing assembly hole; 7. Shaft hole; 8. Outer sleeve; 9. Annular mounting cavity; 10. External heat dissipation cavity; 11. Internal heat dissipation cavity Heat chamber; 12, rear circulation channel; 13, front circulation channel; 14, impeller; 15, groove; 16, first annular step; 17, annular confluence groove; 18, second annular step; 19, first sealing groove; 20, first sealing ring; 21, third annular step; 22, second sealing groove; 23, second sealing ring; 24, convex ring; 25, sealing ring; 26, heat dissipation fin; 27, third sealing groove; 28, third sealing ring. DETAILED DESCRIPTION

[0016] The specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings.

[0017] like Figure 1~Figure 4 The internal circulation cooling brushless motor for an industrial axial flow fan shown in the figure comprises a housing 1, a stator assembly 2 fixedly arranged in the housing 1, and a rotor assembly 3 rotatably connected in the housing 1 and coaxially arranged with the stator assembly 2, one end of the rotating shaft 302 of the rotor assembly 3 extends out of the housing 1, and the housing 1 comprises a front cover 101, a cylinder 102 and a rear seat 103 connected in sequence.

[0018] The front end surface of the rear seat 103 is provided with a rear bearing assembly hole 4, and a center sleeve 5 extending toward the front cover 101 is coaxially arranged at the periphery of the rear bearing assembly hole 4, the inner diameter of the center sleeve 5 is larger than the outer diameter of the rotor core 301, the outer edge of the rear seat 103 is connected to the rear end of the cylinder body 102, the rotor assembly 3 is arranged in the center sleeve 5, and the rear end of the rotating shaft 302 of the rotor assembly is rotatably connected in the rear bearing assembly hole 4 through a bearing.

[0019] The front cover 101 is provided with a front bearing assembly hole 6 and an axial hole 7 which are connected to each other. The front bearing assembly hole 6 and the axial hole 7 are coaxial. The axial hole 7 is located at the front part of the front cover 101. The front cover 101 is provided with an outer sleeve 8 extending toward the rear seat 103. The outer sleeve 8 is coaxial with the axial hole 7. The outer edge of the front cover 101 is connected to the front end of the cylinder body 102. The front end of the rotating shaft 302 of the rotor assembly 3 is rotatably connected in the front bearing assembly hole 6 through a bearing, and passes through the axial hole 7 to extend out of the front cover 101. The rotating shaft 302 is rotatably connected to the axial hole 7.

[0020] The center sleeve 5 is inserted into the outer sleeve 8, the front end of the center sleeve 5 is sealed with the front cover 101, the rear end of the outer sleeve 8 is sealed with the rear seat 103, an annular installation cavity 9 is formed between the center sleeve 5 and the outer sleeve 8, and the stator assembly 2 is installed in the annular installation cavity 9.

[0021] The cylinder body 102 is sleeved on the outside of the outer sleeve 8 and an outer heat dissipation cavity 10 is formed between the outer sleeve 8, and an annular inner heat dissipation cavity 11 is formed between the central sleeve 5 and the rotor assembly 3. A plurality of rear circulation channels 12 connecting the inner heat dissipation cavity 11 and the outer heat dissipation cavity 10 are arranged in the rear seat 103, and a plurality of front circulation channels 13 connecting the inner heat dissipation cavity 11 and the outer heat dissipation cavity 10 are arranged in the front cover 101. An impeller 14 is connected to the rotating shaft 302 of the rotor assembly 3, and the impeller 14 is located in the inner heat dissipation cavity 11. When the impeller 14 rotates with the rotating shaft 302, the cooling medium in the inner heat dissipation cavity 11 flows, forming a circulation flow of the cooling medium from the inner heat dissipation cavity 11 to the outer heat dissipation cavity 10 and then back to the inner heat dissipation cavity 11.

[0022] The cylinder 102 includes a coaxially arranged front ring 102a, a rear ring 102b, a cylinder body 102c formed by winding a corrugated plate, and a head 102d for connecting the end of the cylinder body 102c with the front ring 102a and the rear ring 102b. The inner and outer walls of the cylinder body 102c are respectively circumferentially evenly distributed with a large number of grooves 15 extending along the axial direction thereof. The outer diameters of the front ring 102a and the rear ring 102b are equal to the outer diameters of the rear seat 103 and the front cover 101. The bottom of the groove 15 on the outside of the cylinder body 102c is flush with the outer circumferential surface of the front ring 102a or the rear ring 102b.

[0023] Since the barrel 102c is exposed outside the outer diameter of the front ring 102a and the rear ring 102b, when the industrial axial flow fan is working, the airflow can flow along the groove 15 on the barrel 102c, thereby quickly cooling the barrel 102c, and the cooling medium inside the barrel 102c can also be quickly cooled. After returning to the inner heat dissipation cavity 11, the cooling medium with reduced temperature can cool the inner side of the stator assembly 2 and the rotor assembly 3, thereby fully reducing the operating temperature of the motor. When cooling the motor, no external cooling medium will be introduced, and no internal contamination of the motor will occur.

[0024] The cooling medium used in this embodiment is preferably dry and clean air, and conventional inert gas or heat transfer oil may also be used in actual applications.

[0025] In this embodiment, the outer edge of the front end of the rear seat 103 radially shrinks inward to form a first annular step 16, the rear ring 102b is fixedly welded to the outer edge of the first annular step 16, and an annular confluence groove 17 is formed between the circumferential surface of the rear ring 102b and the first annular step 16. One end of each of the rear circulation channels 12 is circumferentially uniformly distributed on the circumferential surface of the first annular step 16 and is connected to the annular confluence groove 17. The other end of each of the rear circulation channels 12 extends to the periphery of the rear bearing assembly hole 4 and is uniformly distributed along the circumferential direction. The front end of the circumferential surface of the first annular step 16 radially shrinks inward to form a second annular step 18, the outer sleeve 8 is connected to the second annular step 18, and the circumferential surface of the second annular step 18 radially shrinks to form a first sealing groove 19. A first sealing ring 20 is embedded in the first sealing groove 19, and the first sealing ring 20 abuts against the inner wall of the outer sleeve 8 to achieve sealing.

[0026] The rear seat 103 of this structure is convenient for opening the rear circulation flow channel 12 and can achieve a good sealing connection with the outer sleeve 8 and the cylinder body 102 at the same time.

[0027] The outer edge of the front cover 101 in this embodiment is provided with a third annular step 21 facing the rear seat 103, the outer circumferential surface of the third annular step 21 is the outer wall of the outer sleeve 8, a second annular sealing groove 22 is coaxially opened on the platform surface of the third annular step 21, a second sealing ring 23 is arranged inside the second sealing groove 22, and a convex ring 24 cooperating with the second sealing groove 22 is arranged on the front end surface of the front ring 102a, the convex ring 24 is inserted into the second sealing groove 22 and seals against the second sealing ring 23. One end of each of the front circulation channels 13 is uniformly distributed on the circumferential surface of the third annular step 21, and the other end of each of the front circulation channels 13 extends to the periphery of the front bearing assembly hole 6 and is uniformly distributed along the circumferential direction.

[0028] The front cover 101 of this structure is convenient for opening the front circulation flow channel 13 and can achieve a good sealing connection with the central sleeve 5 and the cylinder body 102 at the same time.

[0029] like Figure 3 As shown, the front end of the central sleeve 5 is inserted into a third sealing groove 27 opened on the front cover 101 and is sealed by a third sealing ring 28 embedded in the third sealing groove 27 .

[0030] In this embodiment, the sum of the flow areas of the rear circulation channel 12 is preferably greater than the sum of the flow areas of all the front circulation channels 13. When the motor rotates forward, the impeller 14 drives the cooling medium to flow along the inner heat dissipation cavity 11, the rear circulation channel 12, the outer heat dissipation cavity 10, the front circulation channel, and the inner heat dissipation cavity 11. Figure 1The advantage of this is that since the circulation efficiency of the rear circulation channel 12 is greater than that of the front circulation channel 13, a slightly lower pressure is formed in the inner heat dissipation cavity 11 to reduce the shaft sealing pressure between the rotating shaft 302 and the shaft hole 7 to avoid leakage of the cooling medium.

[0031] The rotating shaft 302 in this embodiment is sealedly connected to the shaft hole 7 via a sealing ring 25 , and the rotating shaft 302 can rotate relative to the sealing ring 25 .

[0032] The impeller 14 is preferably disposed between the rotor core 301 and the rear seat 103 , and the impeller 14 and the driving end of the rotating shaft 302 extending outside the housing 1 are disposed at both ends of the rotor core 301 , which can improve the rotation stability of the rotor assembly 3 .

[0033] The rear bearing assembly hole 4 in this embodiment is a blind hole, which can prevent leakage of cooling medium or external air from entering the motor.

[0034] In order to further improve the heat dissipation effect and improve the strength of the motor housing 1, the present embodiment preferably has a large number of heat dissipation fins 26 axially extending along the outer sleeve 8 evenly distributed in the circumferential direction of the outer heat dissipation cavity 10, each heat dissipation fin 26 is welded to the barrel 102c of the barrel 102, and each heat dissipation fin 26 is arranged in a respective groove 15 on the inner wall of the barrel 102c, and both ends of each heat dissipation fin 26 are respectively welded to the two heads 102d, and the end of the heat dissipation fin 26 away from the inner wall of the barrel 102c abuts against the outer sleeve 8.

[0035] The heat dissipation fins 26 and the barrel 102c are welded, so their thermal conductivity is higher, and the cooling medium flowing through the heat dissipation fins 26 can obtain a faster cooling effect. At the same time, the heat dissipation fins 26 abut against the outer sleeve 8, which can also conduct the heat on the outer sleeve 8 to the outside, thereby improving the heat dissipation efficiency of the outer sleeve 8.

[0036] The working process of the present invention is: Figure 1 As shown, the motor is assembled in a clean environment, and then installed on the industrial axial flow fan. After starting the motor, the shaft 302 drives the industrial axial flow fan to rotate, and the industrial axial flow fan drives the airflow to flow from the rear to the front of the motor. The flow of air cools the motor housing 1, especially the barrel 102c of the barrel 102, and cools the air in the outer heat dissipation cavity 10. The shaft 302 also drives the impeller 14 to rotate, and the impeller 14 drives the hot air in the inner heat dissipation cavity 11 to flow to the rear circulation channel 12 and enter the outer heat dissipation cavity 10 for heat dissipation, while the air in the outer heat dissipation cavity 10 passes through the front circulation channel 13 and returns to the inner heat dissipation cavity 11 to dissipate heat on the inner side of the stator assembly 2 and the rotor assembly 3.

[0037] The above embodiments are only illustrative of the principles and effects of the invention, as well as some embodiments of its application, and are not intended to limit the invention. It should be pointed out that a person skilled in the art can make several modifications and improvements without departing from the inventive concept of the invention, and all of these belong to the protection scope of the invention.

Claims

1. An internal circulation cooling brushless motor for an industrial axial flow fan, comprising a housing (1), a stator assembly (2) fixedly arranged in the housing (1), and a rotor assembly (3) rotatably connected in the housing (1) and coaxially arranged with the stator assembly (2), wherein one end of a rotating shaft (302) of the rotor assembly (3) extends out of the housing (1), and is characterized in that: The housing (1) comprises a front cover (101), a cylinder (102) and a rear seat (103) which are connected in sequence; The front end surface of the rear seat (103) is provided with a rear bearing assembly hole (4), and a central sleeve (5) extending toward the front cover (101) is coaxially arranged on the periphery of the rear bearing assembly hole (4), the inner diameter of the central sleeve (5) is larger than the outer diameter of the rotor core (301), the outer edge of the rear seat (103) is connected to the rear end of the cylinder (102), and the rotor assembly (3) is arranged in the central sleeve (5); The front cover (101) is provided with a front bearing assembly hole (6) and an axial hole (7) which are connected to each other. The front bearing assembly hole (6) and the axial hole (7) are coaxial. The axial hole (7) is located at the front of the front cover (101). The front cover (101) is provided with an outer sleeve (8) extending toward the rear seat (103). The outer sleeve (8) is coaxial with the axial hole (7). The outer edge of the front cover (101) is connected to the front end of the cylinder body (102). The central sleeve (5) is inserted into the outer sleeve (8), the front end of the central sleeve (5) is sealedly connected to the front cover (101), the rear end of the outer sleeve (8) is sealedly connected to the rear seat (103), an annular mounting cavity (9) is formed between the central sleeve (5) and the outer sleeve (8), and the stator assembly (2) is mounted in the annular mounting cavity (9); The cylinder (102) is sleeved on the outside of the outer sleeve (8) and forms an outer heat dissipation cavity (10) with the outer sleeve (8); an annular inner heat dissipation cavity (11) is formed between the central sleeve (5) and the rotor assembly (3); a plurality of rear circulation channels (12) connecting the inner heat dissipation cavity (11) and the outer heat dissipation cavity (10) are arranged in the rear seat (103); a plurality of front circulation channels (13) connecting the inner heat dissipation cavity (11) and the outer heat dissipation cavity (10) are arranged in the front cover (101); an impeller (14) is connected to the rotating shaft (302) of the rotor assembly (3); the impeller (14) is located in the inner heat dissipation cavity (11); The cylinder (102) comprises a coaxially arranged front ring (102a), a rear ring (102b), a cylinder body (102c) formed by winding a corrugated plate, and a head (102d) for connecting the end of the cylinder body (102c) with the front ring (102a) and the rear ring (102b); the inner and outer walls of the cylinder body (102c) are respectively circumferentially evenly provided with a large number of grooves (15) extending along the axial direction thereof; the outer diameters of the front ring (102a) and the rear ring (102b) are equal to the outer diameters of the rear seat (103) and the front cover (101); and the bottom of the grooves (15) outside the cylinder body (102c) is flush with the outer circumferential surface of the front ring (102a) or the rear ring (102b).

2. The internal circulation cooling brushless motor for industrial axial flow fans according to claim 1 is characterized in that: The front end outer edge of the rear seat (103) contracts radially inward to form a first annular step (16); the rear ring (102b) is fixedly welded to the outer edge of the first annular step (16); an annular confluence groove (17) is formed between the circumferential surface of the rear ring (102b) and the first annular step (16); one end of each of the rear circulation channels (12) is evenly distributed on the circumferential surface of the first annular step (16) and communicates with the annular confluence groove (17); the other end of each of the rear circulation channels (12) extends to the periphery of the rear bearing assembly hole (4) and is evenly distributed along the circumferential direction; the front end of the circumferential surface of the first annular step (16) contracts radially inward to form a second annular step (18); the outer sleeve (8) is butted against the second annular step (18); the circumferential surface of the second annular step (18) contracts radially to form a first sealing groove (19); a first sealing ring (20) is embedded in the first sealing groove (19); the first sealing ring (20) abuts against the inner wall of the outer sleeve (8) to achieve sealing.

3. The internal circulation cooling brushless motor for industrial axial flow fans according to claim 1, characterized in that: The outer edge of the front cover (101) is provided with a third annular step (21) facing the rear seat (103); the outer circumferential surface of the third annular step (21) is the outer wall of the outer sleeve (8); a second annular sealing groove (22) is coaxially provided on the platform surface of the third annular step (21); a second sealing ring (23) is provided inside the second sealing groove (22); a convex ring (24) cooperating with the second sealing groove (22) is provided on the front end surface of the front ring (102a); the convex ring (24) is inserted into the second sealing groove (22) and is in sealing contact with the second sealing ring (23); One end of each of the front circulation channels (13) is uniformly distributed on the circumferential surface of the third annular step (21) in the circumferential direction, and the other end of each of the front circulation channels (13) extends to the periphery of the front bearing assembly hole (6) and is uniformly distributed in the circumferential direction.

4. The internal circulation cooling brushless motor for industrial axial flow fans according to claim 1, characterized in that: The sum of the flow areas of all the rear circulation flow channels (12) is greater than the sum of the flow areas of all the front circulation flow channels (13).

5. The internal circulation cooling brushless motor for industrial axial flow fans according to claim 1, characterized in that: The rotating shaft (302) is sealedly connected to the shaft hole (7) via a sealing ring (25), and the rotating shaft (302) can rotate relative to the sealing ring (25).

6. The internal circulation cooling brushless motor for industrial axial flow fans according to claim 1, characterized in that: The impeller (14) is arranged between the rotor core (301) and the rear seat (103).

7. The internal circulation cooling brushless motor for industrial axial flow fans according to claim 1, characterized in that: The outer heat dissipation cavity (10) and the inner heat dissipation cavity (11) are both filled with heat transfer oil.

8. The internal circulation cooling brushless motor for industrial axial flow fans according to claim 1, characterized in that: The rear bearing assembly hole (4) is a blind hole.

9. The internal circulation cooling brushless motor for industrial axial flow fans according to claim 1, characterized in that: A large number of heat dissipation fins (26) extending axially along the outer sleeve (8) are evenly distributed in the inner circumference of the outer heat dissipation cavity (10); each heat dissipation fin (26) is welded to the barrel (102c) of the barrel (102); each heat dissipation fin (26) is arranged in a groove (15) on the inner wall of the barrel (102c); two ends of each heat dissipation fin (26) are respectively welded to two heads (102d); and one end of the heat dissipation fin (26) away from the inner wall of the barrel (102c) abuts against the outer sleeve (8).

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