CN210404909U - Outer rotor brushless motor and outer rotor thereof - Google Patents

Abstract

The utility model provides an external rotor brushless motor and external rotor thereof, this brushless motor external rotor include casing, pivot and establish a plurality of magnets in the casing, the casing includes the side shell portion, establish in the preceding shell portion that side shell portion front side and be connected with the pivot and establish the output shaft in the front shell portion front side, the casing is integrated into one piece and be the open shape in rear portion, the front end of pivot is connected with preceding shell portion in the casing appearance chamber, the output shaft is coaxial with the pivot. When the brushless motor outer rotor works, the rotating shaft drives the shell to rotate, and the shell is integrally formed, so that the shell has high reliability under the working conditions of high rotating speed and large vibration of the motor; and the casing directly includes the output shaft, conveniently is connected with external load, output power.

Description

Outer rotor brushless motor and outer rotor thereof

Technical Field

The utility model belongs to the technical field of the motor and specifically relates to an outer rotor brushless motor and outer rotor thereof is related to.

Background

The brushless direct current motor is composed of a motor main body and a driver, and is a typical electromechanical integration product. The brushless motor is a motor without a brush and a commutator (or a collecting ring), is also called a commutator motor, is different from a brush direct current motor, does not use a mechanical brush device, replaces a carbon brush commutator with a Hall sensor, takes neodymium iron boron as a permanent magnet material of a rotor, has great advantages in performance compared with a common traditional direct current brush motor, and has the advantages of high efficiency, low energy consumption, low noise, ultra-long service life, high reliability, servo control, stepless frequency conversion speed regulation, relatively low cost, simplicity and easiness in use, and is the most ideal speed regulation motor at present. The direct current brushless motor is widely applied to various industries such as garden tools, electric tools, automobile water pumps, industrial automation, medical appliances and the like.

Referring to fig. 1 to 4, the structure of the outer rotor brushless motor on the market at present is composed of a stator assembly 400 and a rotor assembly 300. The rotor assembly 300 generally comprises an annular housing 302, an end cover 301 arranged on the front side of the annular housing 302, a magnet 303 arranged in the annular housing 302, a rotating shaft 304 and a clamp spring 305, wherein the rotating shaft 304 is connected with the end cover 301 and penetrates out of the end cover 301, and the end cover 301 is connected with the annular housing 302 in an interference fit mode and is bonded by means of glue. When the finished motor product is used in the whole product, the rotor has large rotational inertia, the motor vibrates greatly, the temperature rise of the motor gradually rises under the condition of high rotational speed for a long time, the glue has failure hidden trouble in a high-temperature state, and the end cover 301 and the annular shell 302 have poor matching reliability and falling hidden trouble.

SUMMERY OF THE UTILITY MODEL

The to-be-solved technical problem of the utility model lies in that, to the above-mentioned defect in the correlation technique, a brushless motor external rotor that magnet fixed strength is high is provided.

The utility model provides a technical scheme that its technical problem adopted includes: a brushless motor outer rotor is constructed and comprises a shell, a rotating shaft and a plurality of magnets arranged in the shell, wherein the shell comprises a side shell part, a front shell part and an output shaft, the front shell part is arranged on the front side of the side shell part and connected with the rotating shaft, the output shaft is arranged on the front side of the front shell part, the shell is integrally formed and is in a shape with the rear part opened, the front end of the rotating shaft is arranged in a cavity of the shell and connected with the front shell part, and the output shaft is coaxial with the rotating shaft.

The magnetic positioning device comprises a casing, a plurality of first magnet positioning grooves are formed in the casing, a plurality of second magnet positioning grooves are formed in the front side of the casing, a plurality of first magnet positioning grooves are formed in the rear side of the casing, a plurality of second magnet positioning grooves are formed in the front side of the baffle, the front ends of the magnets are matched with the first magnet positioning grooves in a one-to-one correspondence mode, the rear ends of the magnets are matched with the second magnet positioning grooves in a one-to-one correspondence mode, and the positions of the magnets are limited.

Furthermore, one of the casing and the retainer is provided with at least one first positioning protrusion, and the other one of the casing and the retainer is provided with at least one first positioning concave part matched with the first positioning protrusion, so that the retainer is circumferentially fixed.

Further, the at least one first positioning protrusion and the at least one first positioning recess are located at the periphery of the rotating shaft.

Further, the first positioning protrusion is in interference fit with the first positioning concave portion.

Further, the outer wall of the retainer is in interference fit with the inner wall of the casing.

Further, one of the shell and the baffle is provided with a second positioning protrusion, and the other is provided with a second positioning concave part matched with the second positioning protrusion, so that the baffle is fixed in the circumferential direction.

Further, the outer wall of baffle and the inner wall interference fit of casing.

Further, the housing also includes an output gear provided on the output shaft.

Further, in the case, the front case portion is provided with a connection hole, and a front end of the rotation shaft is inserted into the connection hole and is coaxial with the output shaft.

Furthermore, the shell is also provided with an axial process through hole which penetrates through the center of the output shaft and is communicated with the connecting hole and the outside of the shell.

Furthermore, the front end of the rotating shaft and the connecting hole are respectively provided with corresponding flat positions.

Further, the magnet is attached to the inner side of the casing, the contact surface of the magnet and the casing is in an arc shape corresponding to the inner wall of the casing, and the reverse side of the contact surface is a plane.

Furthermore, the casing is provided with at least one casing heat dissipation hole, and the retainer is provided with a retainer heat dissipation hole corresponding to the position of the casing heat dissipation hole so as to allow the inside of the casing to be communicated with the outside air.

The utility model provides a technical scheme that its technical problem adopted still includes: an outer rotor brushless motor is constructed, and comprises a stator and the brushless motor outer rotor combined with the stator.

Implement the technical scheme of the utility model, following beneficial effect has at least: when the brushless motor outer rotor works, the rotating shaft drives the shell to rotate, and the shell is integrally formed, so that the shell has high reliability under the working conditions of high rotating speed and large vibration of the motor; and the casing directly includes the output shaft, conveniently is connected with external load, output power.

Drawings

The invention will be further explained with reference to the drawings and examples, wherein:

fig. 1 is a right side view of an outer rotor brushless motor in the background art.

Fig. 2 is a front view of an outer rotor assembly of an outer rotor brushless motor in the related art.

Fig. 3 is a right side view of an outer rotor assembly of the outer rotor brushless motor in the related art.

Fig. 4 is a sectional view taken at a position a-a in fig. 2.

Fig. 5 is a right side view of an outer rotor brushless motor according to an embodiment of the present invention.

Fig. 6 is an exploded view of the outer rotor of fig. 5.

Fig. 7-8 are perspective views of the outer rotor of fig. 5.

Fig. 9-10 are perspective cross-sectional views of the outer rotor of fig. 5.

Fig. 11 is a perspective view of a casing of an outer rotor according to an embodiment of the present invention.

Fig. 12 is a perspective sectional view of the cabinet of fig. 11.

Fig. 13 to 14 are perspective views of a retainer of an outer rotor according to an embodiment of the present invention.

Fig. 15 is a perspective view of a baffle of an outer rotor according to an embodiment of the present invention.

Fig. 16 is a perspective view of a rotation shaft of an outer rotor according to an embodiment of the present invention.

Fig. 17 is a perspective view of the magnet 14 according to an embodiment of the present invention.

The reference numerals in the figures denote: brushless motor external rotor 1, casing 11, front shell 111, side shell 112, output shaft 113, output gear 114, connecting hole 115, through hole 116, casing heat dissipation hole 117, holder 12, first positioning recess 121, first positioning protrusion 122, first magnet positioning slot 123, holder heat dissipation hole 124, baffle 13, second positioning recess 131, second positioning protrusion 132, second magnet positioning slot 133, magnet 14, 141 arc surface, 142 plane, rotating shaft 15, positioning boss 151, flat position 152, brushless motor stator 2.

Detailed Description

In order to clearly understand the technical features, objects, and effects of the present invention, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, it should be understood that the directions or positional relationships indicated by "front", "back", "upper", "lower", "left", "right", "longitudinal", "horizontal", "vertical", "horizontal", "top", "bottom", "inner", "outer", "head", "tail", etc. are configured and operated in specific directions based on the directions or positional relationships shown in the drawings, and are only for convenience of describing the present invention, but do not indicate that the device or element referred to must have a specific direction, and thus, should not be construed as limiting the present invention.

It is also noted that, unless expressly stated or limited otherwise, the terms "mounted," "connected," "secured," "disposed," and the like are intended to be inclusive and mean, for example, that they may be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. When an element is referred to as being "on" or "under" another element, it can be "directly" or "indirectly" on the other element or intervening elements may also be present. The terms "first", "second", "third", etc. are only for convenience in describing the present technical solution, and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated, whereby the features defined as "first", "second", "third", etc. may explicitly or implicitly include one or more of such features. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.

In the following description, for purposes of explanation and not limitation, specific details are set forth, such as particular system structures, techniques, etc. in order to provide a thorough understanding of the embodiments of the invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail.

Referring to fig. 5 to 16, a brushless motor external rotor 1 according to an embodiment of the present invention includes a housing 11, a rotating shaft 15, and a plurality of magnets 14 circumferentially disposed inside the housing 11, the housing 11 includes a side housing 112, a front housing 111 disposed in front of the side housing 112 and connected to the rotating shaft 15, and an output shaft 113 disposed in front of the front housing 111, the housing 11 is integrally formed and has a shape with an open rear portion, that is, the front housing 111, the side housing 112, and the output shaft 113 are integrally formed, and the output shaft 113 can be connected to an external load. The front end of the rotating shaft 15 is connected with the front shell part 111 in the cavity of the shell 11, and the output shaft 113 is coaxial with the rotating shaft 15. When the brushless motor outer rotor 1 works, the rotating shaft 15 drives the casing 11 to rotate. Because the casing 11 is integrally formed, compared with the rotor assembly in the current market, the casing 11 has high reliability under the working conditions of high rotating speed and large vibration of the motor, and the hidden danger of falling of the end cover is avoided; and the housing 11 directly includes an output shaft 113 for easy connection with an external load to output power.

In addition, referring to fig. 1 to 4, in an outer rotor brushless motor currently on the market, in terms of a fixing manner of a magnet 303 of a rotor, a magnet groove is formed in an end cover 301, the end cover 301 and an annular housing 302 are in interference fit with each other by adding glue, then the magnet 303 is positioned through the magnet groove of the end cover 301, and the magnet 303 and the annular housing 302 are fixed by bonding with glue. However, when the motor operates under the working conditions of high rotating speed and large vibration, the reliability of the bonding of the magnet 303 is poor, and the hidden trouble that the magnet 303 falls off is easy to occur.

Therefore, in an embodiment of the present invention, the brushless motor outer rotor 1 may further include a holder 12 and a baffle 13, the holder 12 is circumferentially and axially fixedly disposed at a front portion of an inner cavity of the housing 11, the baffle 13 is circumferentially and axially fixedly disposed at a rear portion of the housing 11, a plurality of first magnet positioning grooves 123 are disposed at a rear side of the holder 12, the baffle 13 is fixed at the rear portion of the housing 11 to block the plurality of magnets 14, a plurality of second magnet positioning grooves 133 are disposed at a front side of the baffle 13, front ends of the plurality of magnets 14 are fitted with the plurality of first magnet positioning grooves 123 in a one-to-one correspondence, and rear ends of the plurality of magnets 14 are fitted with the plurality of second magnet positioning grooves 133 in a one-to-one correspondence, so as to limit positions of the. The magnets 14 may be magnetic steel or other magnets 14 suitable for an outer rotor of an electric machine, but are not limited thereto. According to the brushless motor outer rotor 1, the magnets 14 are fixed through the retainers 12 and the baffles 13 which are arranged in tandem, so that axial and radial bidirectional positioning is realized, the strength of the magnets in axial and radial matching is greatly improved, the fixing strength of the magnets 14 is enhanced, and the magnets 14 are highly reliable and are not easy to fall off under the working conditions of high rotating speed and large vibration of the motor.

In addition, an adhesive such as glue may be simultaneously added between the magnet 14 and the housing 11, the holder 12, and the baffle 13 to further enhance the fixing strength of the magnet 14.

One of the housing 11 and the holder 12 may be provided with at least one first positioning protrusion 122, and the other may be provided with at least one first positioning recess 121 engaged with the first positioning protrusion 122, so as to circumferentially fix the holder 12, for example, the housing 11 is provided with the first positioning protrusion 122 and the holder 12 is provided with the first positioning recess 121, or the housing 11 is provided with the first positioning recess 121 and the holder 12 is provided with the first positioning protrusion 122. Regarding the number and positions of the first positioning protrusions 122 and the first positioning recesses 121, the first positioning protrusions 122 and the first positioning recesses 121 may be located on the periphery of the rotating shaft 15, the number of the first positioning protrusions 122 and the first positioning recesses 121 may be one or more, for example, two, three, four, and the like, and when the number of the first positioning protrusions 122 and the first positioning recesses 121 is two or more, the first positioning protrusions 122 and the first positioning recesses 121 are circumferentially spaced around the rotating shaft 15. An interference fit is preferably adopted as the fit of the first positioning projection 122 and the first positioning recess 121 to enhance the axial fixation of the cage 12. Specifically, referring to the embodiment shown in fig. 7 to 14, the first positioning recess 121 is two or more positioning holes spaced around the rotation shaft 15 in the circumferential direction, the first positioning protrusion 122 is two or more positioning posts provided at the front side of the holder 12 and matched with the two positioning holes in a one-to-one correspondence manner, and the positioning posts are inserted into the positioning holes and are in interference fit.

The material of the retainer 12 can use PA6+ 30% GF, and the material has high mechanical strength and hardness, high rigidity, high temperature resistance, capability of being molded and manufactured and low cost.

The outer wall of the cage 12 may have an interference fit with the inner wall of the casing 11 to allow circumferential and axial fixation of the cage 12. Specifically, referring to the embodiment shown in fig. 7-14, the shape of the holder 12 is adapted to the cavity of the housing 11, and is disposed at the front of the inner cavity of the housing 11, and the holder is annular and has a central hollow portion for avoiding the rotating shaft 15 and/or other structures of the brushless motor, and the outer wall of the holder 12 is in interference fit with the inner wall of the housing 11.

At least one casing heat dissipation hole 117 may be formed in the casing 11, and the holder 12 is provided with holder heat dissipation holes 124 corresponding to the casing heat dissipation holes 117, so as to allow air inside the casing 11 to circulate with the outside, thereby facilitating heat dissipation of the motor, reducing temperature rise of the motor, and prolonging the service life of the motor. Preferably, a plurality of housing louvers 117 are provided at the front case portion 111 and/or the side case portions 112, or at corners where the front case portion 111 and the rear case portion of the housing 11 are connected (see fig. 7 to 12), and are circumferentially spaced around the rotation shaft 15, and the number and positions of the holder louvers 124 correspond to the housing louvers 117.

One of the housing 11 and the baffle 13 may be provided with a second positioning protrusion 132, and the other may be provided with a second positioning recess 131 engaged with the second positioning protrusion 132, so that the baffle 13 is circumferentially fixed by the engagement of the second positioning protrusion 132 and the second positioning recess 131. Regarding the matching of the baffle 13 and the casing 11, the shape of the baffle 13 corresponds to the radial shape of the casing 11, and the baffle 13 is embedded inside the casing 11, that is, an embedded type is adopted between the casing 11 and the baffle 13; the outer wall of the baffle 13 is in interference fit with the inner wall of the housing 11 to axially secure the baffle 13. Regarding the structure of the baffle 13, the baffle 13 is annular and has a hollow portion to avoid the rotation shaft 15 and/or other structures of the brushless motor, and the second positioning recess 131 may have a groove shape. The second positioning protrusion 132 is disposed on the outer edge of the baffle 13, and the mating surface of the housing 11 and the baffle 13 is provided with the second positioning concave portion 131, or vice versa, the second positioning concave portion 131 is disposed on the outer edge of the baffle 13, and the mating surface of the housing 11 and the baffle 13 is provided with the second positioning protrusion 132, so that the second positioning protrusion 132 is clamped in the second positioning concave portion 131. The second positioning protrusions 132 may be at least one and circumferentially spaced along the outer periphery of the barrier 13, and the number and positions of the second positioning recesses 131 correspond to those of the first positioning protrusions 122, for example, referring to the embodiment of fig. 7-10 and 15, there are two second positioning protrusions 132.

The magnet 14 is attached to the inner side of the machine shell 11, the contact surface of the magnet 14 and the machine shell 11 is in an arc shape corresponding to the inner wall of the machine shell 11, and the reverse side of the contact surface is a plane, so that the material cost of the magnet 14 is reduced, the cogging torque of the magnet 14 is reduced, and the motor efficiency is improved.

Referring to fig. 1-4, when an outer rotor brushless motor in the market is used, there are some situations in which the requirement for the torque of the motor is high, and especially in electric and garden tools, in order to increase the output torque of the motor, a gear is usually assembled at the output end of the rotating shaft of the motor, so as to reduce the rotating speed of the motor and increase the torque. The gear inner hole and the rotating shaft are in interference fit, and when the gear and the motor shaft are assembled, the shaft lift is easily affected by radial force to extrude the bearing, so that the motor bearing is poor in sound and short in service life.

Therefore, in an embodiment of the present invention, the housing 11 of the brushless motor outer rotor 1 may further include a coaxial output gear 114 disposed on the output shaft 113, that is, the front housing part 111, the side housing part 112, the output shaft 113 and the output gear 114 are integrally formed. The output gear 114 can be directly matched with a reducer for installation, so that the output torque of the motor after the complete machine is assembled is increased, the application requirements of small volume and large torque can be met, and the output reliability is greatly improved because the output gear 114 and the machine shell 11 are integrally formed; and because the output gear does not need to be assembled additionally, the problems that the shaft lift is easy to extrude the bearing under the influence of radial force, the sound of the motor bearing is poor and the service life of the motor bearing is shortened due to the fact that the gear and the motor shaft lift are assembled are avoided.

Further, in the housing 11, a connection hole 115 coaxial with the output shaft 113 may be provided inside the front housing part 111, and the front end of the rotation shaft 15 is inserted into the connection hole 115 and coaxial with the output shaft 113; the radial dimension of the output shaft 113 may be larger than that of the rotation shaft 15, and the coupling hole 115 is deeply inserted into the output shaft 113, thereby allowing the rotation shaft 15 to have a sufficient insertion depth. Preferably, the casing 11 may further have an axial through hole 116, the through hole 116 passes through the center of the output shaft 113 and communicates with the connection hole 115, so as to exhaust the gas pressure in the connection hole 115, thereby avoiding the problem that the shaft is difficult to press into the inner hole of the casing 11 due to the sealed gas pressure when the inner hole of the casing 11 is matched with the shaft; the interference magnitude can be increased, the process assembly difficulty of the rotating shaft 15 and the shell 11 is reduced, the radial torsional looseness force is increased, and the matching strength and the reliability are improved. In addition, the front end of the rotating shaft 15 and the connecting hole 115 can be respectively provided with corresponding flat positions 152, when the front end of the rotating shaft 15 is inserted into the connecting hole 115, the flat positions 152 at the front end of the rotating shaft 15 correspond to the flat positions 152 of the connecting hole 115, so that the radial twisting and loosening phenomena of the shaft and the machine shell 11 in the large-torque application process can be prevented, and the reliability is improved. The rotating shaft 15 may be provided with a positioning boss 151, the front end of the rotating shaft 15 is inserted into the connecting hole 115, and the front side of the positioning boss abuts against the casing 11, so as to facilitate the shaft lifting control.

The utility model discloses an embodiment's external rotor brushless motor, including stator 2 and with the brushless motor external rotor 1 in the above-mentioned embodiment of stator 2 combination, the motor during operation, rotor 1 is rotatory for stator 2.

To sum up, the outer rotor brushless motor and the outer rotor thereof of the utility model, because the casing 11 of the outer rotor is integrally formed, the casing 11 has high reliability under the working conditions of high rotating speed and large vibration of the motor; the shell 11 directly comprises an output shaft 113 which is conveniently connected with an external load to output power; the magnet 14 is fixed by the retainer 12 and the baffle 13 which are arranged in tandem, so that the fixing strength of the magnet 14 is greatly enhanced, the reliability is high under the working conditions of high rotating speed and large vibration of the motor, and the magnet 14 is not easy to fall off; the casing 11 can also include an integrally formed output shaft 113 and even an output gear 114, which is used for connecting with an external load, and can be directly matched with a speed reducer for installation, so that the output torque of the motor after the whole machine is assembled is increased, the application requirements of small volume and large torque can be realized, and the reliability is very high; and because the output gear 114 does not need to be assembled additionally, the problems that the shaft lift is easy to extrude the bearing under the influence of radial force and the motor bearing is poor in sound and short in service life caused by assembling the gear with the motor shaft lift are avoided.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not intended to limit the present invention, which may be modified, combined, and varied by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.

Claims (15)

1. The utility model provides a brushless motor external rotor (1), includes casing (11), pivot (15) and establishes a plurality of magnet (14) in casing (11), its characterized in that, casing (11) include side shell portion (112), establish side shell portion (112) front side and with preceding shell portion (111) that pivot (15) are connected and establish preceding shell portion (111) front side output shaft (113), casing (11) are integrated into one piece and are the open shape in rear portion, the front end of pivot (15) is in casing (11) holds the chamber in with preceding shell portion (111) are connected, output shaft (113) with pivot (15) are coaxial.

2. The external rotor (1) of the brushless motor of claim 1, further comprising a retainer (12) and a baffle (13), wherein the retainer (12) is circumferentially and axially fixedly arranged at the front of the inner cavity of the casing (11), the baffle (13) is circumferentially and axially fixedly arranged at the rear of the casing (11), a plurality of first magnet positioning grooves (123) are formed at the rear side of the retainer (12), the baffle (13) is fixedly arranged at the rear of the casing (11), a plurality of second magnet positioning grooves (133) are formed at the front side of the baffle (13), and the front ends of the plurality of magnets (14) are correspondingly matched with the plurality of first magnet positioning grooves (123) one by one while the rear ends of the plurality of magnets are correspondingly matched with the plurality of second magnet positioning grooves (133) one by one to limit the positions of the plurality of magnets (14).

3. The external rotor (1) of a brushless electric machine according to claim 2, wherein at least one first positioning protrusion (122) is provided on one of the casing (11) and the cage (12), and at least one first positioning recess (121) is provided on the other one, which is engaged with the first positioning protrusion (122), to circumferentially fix the cage (12).

4. The external rotor (1) of a brushless electric machine according to claim 3, characterized in that the at least one first positioning protrusion (122) and the at least one first positioning recess (121) are located at the periphery of the rotation shaft.

5. The external rotor (1) of a brushless electric machine according to claim 3, characterized in that the first positioning projection (122) is interference fitted with the first positioning recess (121).

6. The external rotor (1) of a brushless electric machine according to claim 2, characterized in that the outer wall of the cage (12) is interference fitted with the inner wall of the casing (11).

7. The external rotor (1) of a brushless motor of claim 2, wherein one of the casing (11) and the baffle (13) is provided with a second positioning protrusion (132), and the other is provided with a second positioning recess (131) engaged with the second positioning protrusion (132) to circumferentially fix the baffle (13).

8. The external rotor (1) of a brushless electric machine of claim 7, wherein the outer wall of the baffle (13) is interference fit with the inner wall of the casing (11).

9. The external rotor (1) of a brushless motor of claim 2, wherein the casing (11) is provided with at least one casing heat dissipation hole (117), and the retainer (12) is provided with a retainer heat dissipation hole (124) corresponding to the casing heat dissipation hole (117) for circulating air between the inside and the outside of the casing (11).

10. The external rotor (1) of a brushless electric machine according to claim 1, characterized in that the casing (11) further comprises an output gear (114) provided on the output shaft (113).

11. The external rotor (1) of a brushless motor of claim 1, wherein the front housing part (111) is provided with a connection hole (115) in the casing (11), and the front end of the rotation shaft (15) is inserted into the connection hole (115) and is coaxial with the output shaft (113).

12. The external rotor (1) of the brushless motor of claim 11, wherein the casing (11) is further provided with an axial through-hole (116), the through-hole (116) passes through the center of the output shaft (113) and communicates the connecting hole (115) with the outside of the casing (11).

13. The external rotor (1) of a brushless electric machine according to claim 11, characterized in that the front end of the shaft (15) and the connection holes (115) are provided with corresponding flat positions (152), respectively.

14. The external rotor (1) of the brushless motor of claim 1, wherein the magnets (14) are attached to the inner side of the casing (11), the contact surface between the magnets (14) and the casing (11) is arc-shaped corresponding to the inner wall of the casing (11), and the reverse surface of the contact surface is a plane.

15. An external rotor brushless electric machine, characterized by comprising a stator and, in combination with the stator, an external rotor (1) of a brushless electric machine according to any of claims 1-14.

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