Brushless motor

Abstract

The invention relates to the technical field of motors, and provides a brushless motor which comprises a shell, a front cover, a support, a stator assembly, a rotor assembly, a circuit board fixed to the side, away from the shell, of the support and a sensor assembly. The stator assembly is arranged around the rotor assembly and is spaced from the rotor assembly; the rotor assembly comprises a rotating shaft and a permanent magnet fixedly sleeved on the rotating shaft; the rotating shaft comprises a rotating shaft body which is rotationally connected with the front cover and the bracket respectively, and two flat parts which are parallel to each other and are formed by recessing the peripheral side of the rotating shaft body respectively; the sensor assembly comprises sensor magnetic steel and a Hall sensor; the sensor magnetic steel comprises a magnetic steel body and a fixing hole penetrating through the magnetic steel body. The flat part is inserted and fixed in the fixing hole; the magnetizing direction of the permanent magnet is perpendicular to the flat part, and the magnetizing direction of the sensor magnetic steel is perpendicular to the flat part. Compared with the prior art, the brushless motor has the advantages of consistent main and auxiliary magnetic field directions, high rotation data detection precision and good torque performance.

Description

Technical Field

[0001] The invention relates to the technical field of motors, and in particular to a brushless coreless motor. Background Art

[0002] Brushless motors have been widely used in the fields of motors and generators due to their compact structure, high power density, high working efficiency, and significant energy saving and consumption reduction benefits. In recent years, the industrial field has an increasingly urgent demand for equipment that uses brushless motors to directly drive loads. The widespread application of these brushless motor direct-drive equipment will produce immeasurable energy-saving benefits.

[0003] In the related art, most of the existing brushless motors include a front cover, a rotor, a stator wound at intervals on the rotor, a bracket, and a sensor assembly. The front cover and the bracket are respectively arranged at opposite ends of the stator, and the motor is driven by the stator and the rotor to rotate. The stator includes a shell fixed to the front cover and a winding fixed in the shell. The rotor generally includes a rotating shaft and a magnet fixed to the outer peripheral side of the rotating shaft. The motor is driven by the magnet and the winding to rotate. The sensor assembly includes a sensor magnet fixed to the rotating shaft and a Hall sensor fixed to the bracket. The Hall sensor and the sensor magnet are arranged relative to each other. However, the existing sensor magnet and the rotating shaft are matched with round heads, so that the directions of the main magnetic field and the secondary magnetic field are not fixed, forming an arbitrary angle setting of the magnetic field; this is prone to the problem of random interference of the main magnetic field on the secondary magnetic field, resulting in large fluctuations in the detection accuracy and calibration accuracy of the Hall sensor; at the same time, there is also a problem of random interference of the secondary magnetic field on the main magnetic field, resulting in large fluctuations in the torque performance of the motor.

[0004] Therefore, it is necessary to provide a new brushless motor to solve the above technical problems. Summary of the invention

[0005] The object of the present invention is to provide a brushless motor with consistent main and auxiliary magnetic field directions, high rotation data detection accuracy and good torque performance.

[0006] In order to achieve the above object, the present invention provides a brushless motor, which comprises a housing, a front cover and a bracket respectively mounted on the two ends of the housing, a stator assembly fixed to the inner side of the housing, a rotor assembly whose two ends are respectively supported by the front cover and the bracket and form a rotation connection, a circuit board fixed to a side of the bracket away from the housing, and a sensor assembly; the stator assembly is arranged around the rotor assembly and is spaced apart from the rotor assembly; The rotor assembly comprises a rotating shaft and a permanent magnet sleeved and fixed on the rotating shaft; the rotating shaft is rotatably connected with the front cover and the bracket respectively, and the permanent magnet and the stator assembly are spaced apart from each other; the rotating shaft comprises a rotating shaft body rotatably connected with the front cover and the bracket respectively, and two parallel flat parts formed by respectively concavely forming the outer peripheral side of one end of the rotating shaft body close to the circuit board; The sensor assembly comprises a sensor magnet sleeved and fixed on one end of the rotating shaft away from the front cover and a Hall sensor fixed on one side of the circuit board close to the bracket; the Hall sensor is relatively spaced from the sensor magnet and is located within the magnetic field range of the sensor magnet; the sensor magnet comprises a magnet body and a fixing hole formed through the magnet body; the shape of the fixing hole matches the switch at one end of the rotating shaft body close to the circuit board, and the flat portion is inserted and fixed in the fixing hole; Wherein, the magnetization direction of the permanent magnet is perpendicular to the flat portion, and the magnetization direction of the sensor magnetic steel is perpendicular to the flat portion.

[0007] Preferably, the fixing hole comprises two flat edges arranged opposite to each other and two arc-shaped side walls respectively connecting the same end of the two flat edges, and the two flat portions are attached to the two flat edges.

[0008] Preferably, the outer periphery of the magnetic steel body forms two relatively parallel straight edges and two arc-shaped edges respectively connecting the same ends of the two straight edges, and the straight edges are perpendicular to the flat portion.

[0009] Preferably, the shell includes a shell body in the shape of a hollow column, an annular connecting portion formed by one end of the shell body extending radially inwardly, and a positioning hole formed through the connecting portion; the front cover includes a front cover body, an annular first boss formed by a protrusion extending from a side of the front cover body close to the shell, a second boss formed by a protrusion extending from a side of the first boss close to the shell, a positioning column formed by a protrusion extending from a side of the first boss close to the shell, and a through hole passing through the second boss along the axial direction of the second boss; the side of the connecting portion close to the front cover abuts against the first boss, the inner side of the connecting portion is sleeved on the outer periphery of the second boss, and the positioning column is inserted and fixed in the positioning hole; the stator assembly is fixed to the inner side wall of the shell body, and one end of the rotor assembly is inserted in the through hole to form a rotating connection.

[0010] Preferably, the shell also includes a plurality of limit grooves formed by the other end of the shell body being recessed along its axial direction and a limit wall formed in each of the limit grooves and protruding and extending toward the bracket; the bracket includes a bracket body, an annular contact portion formed by the side of the bracket body protruding and extending away from the shell, a limit protrusion formed by the outer peripheral side of the bracket body, and an avoidance groove formed by the outer peripheral side recessed of the bracket body, the limit protrusion and the avoidance groove are distributed along the circumference of the bracket body, and the limit protrusion is located at the notch of the avoidance groove, the bracket body is inserted into one end of the shell body and fixed to the inner side wall of the shell body, the contact portion abuts against the shell body on one side close to the shell body, the limit protrusion is arranged in the limit groove, and the limit wall is arranged in the avoidance groove; the other end of the rotor assembly is supported by the bracket body and forms a rotational connection.

[0011] Preferably, the bracket also includes at least two third bosses formed by protruding and extending from one side of the bracket body away from the outer shell; the circuit board includes a circuit board body and at least two slot structures formed by interval depressions of the circuit board body, and each of the third bosses is respectively arranged in one of the slot structures.

[0012] Preferably, the stator assembly includes a coil winding coaxially arranged with the housing and fixed to the housing.

[0013] Preferably, the brushless motor further comprises a first bearing, the first bearing is sleeved and fixed to one end of the rotating shaft close to the front cover, and the outer periphery of the first bearing is fixed in the front cover.

[0014] Preferably, the brushless motor further comprises a second bearing, wherein the second bearing is sleeved on an end of the rotating shaft away from the front cover, and an outer periphery of the second bearing is fixed in the bracket.

[0015] Preferably, the rotor assembly further comprises an iron core, and the iron core is sleeved and fixed between the rotating shaft and the permanent magnet.

[0016] Compared with the prior art, in the brushless motor of the present invention, the stator assembly is fixed in the housing, the stator assembly is arranged around the rotor assembly and is spaced from the rotor assembly, so that the rotor assembly is rotatably connected to the housing; the permanent magnet and the stator assembly are spaced from each other; the rotating shaft includes a rotating shaft body that is rotatably connected to the front cover and the bracket respectively, and two mutually parallel flat parts that are respectively recessed on the outer peripheral side of one end of the rotating shaft body close to the circuit board; the sensor magnet is fixed to the rotating shaft, and the Hall sensor is fixed to the circuit board and is located within the magnetic field range of the sensor magnet; the sensor magnet includes a magnet body and a magnetic field formed by penetrating the magnet body. The fixing hole is formed by a shape matching a switch at one end of the rotating shaft body close to the circuit board, and the flat portion is inserted and fixed in the fixing hole; the magnetization direction of the permanent magnet is perpendicular to the flat portion, and the magnetization direction of the sensor magnet is perpendicular to the flat portion; in this way, the sensor magnet and the rotating shaft are matched with each other in a double flat manner, and the magnetization direction of the permanent magnet is perpendicular to the flat portion, and the rotor assembly is first assembled and then magnetized; the magnetic field direction of the sensor magnet is perpendicular to the flat portion, and the design of the flat portion ensures the consistency of the directions of the main and secondary magnetic fields, and the mutual interference degree of the main and secondary magnetic fields tends to be consistent, which is beneficial to improving the detection and calibration accuracy of the Hall sensor and the torque performance of the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work, among which: Figure 1 A schematic diagram of the three-dimensional structure of a brushless motor provided in an embodiment of the present invention; Figure 2 A three-dimensional structural exploded view of a brushless motor provided in an embodiment of the present invention; Figure 3 for Figure 1 AA line section view; Figure 4 A schematic diagram of the structure of a housing provided by an embodiment of the present invention; Figure 5 A schematic diagram of the structure of a bracket provided in an embodiment of the present invention; Figure 6 for Figure 1 BB line cross-sectional view; Figure 7 for Figure 6 A partial enlarged view of C.

[0018] Among them, 100, brushless motor, 1, housing, 11, housing body, 12, connecting part, 13, limiting groove, 14, limiting wall, 15, positioning hole, 2, stator assembly, 3, rotor assembly, 31, permanent magnet, 32, iron core, 33, shaft, 331, shaft body, 332, flat part, 4, front cover, 41, front cover body, 42, first boss, 43, second boss, 44, positioning column, 45, through hole, 5, bracket, 51, bracket body, 5 2. Contact portion, 53. Limiting protrusion, 54. Avoiding groove, 55. Third boss, 6. Circuit board, 61. Circuit board body, 62. Notch structure, 7. Outlet terminal, 8. First bearing, 9. Second bearing, 10. Sensor assembly, 101. Sensor magnet, 1011. Magnet body, 10111. Arc edge, 10112. Straight edge, 1012. Fixing hole, 10121. Flat edge, 10122. Side wall, 102. Hall sensor. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] Combination Figures 1 to 7 As shown, an embodiment of the present invention provides a brushless motor 100, which includes a housing 1, a front cover 4 and a bracket 5 respectively installed at both ends of the housing 1, a stator assembly 2 fixed to the inner side of the housing 1, a rotor assembly 3 respectively supported by the front cover 4 and the bracket 5 and forming a rotational connection, a circuit board 6 fixed to a side of the bracket 5 away from the housing 1, and a sensor assembly 10, wherein the stator assembly 2 is arranged around the rotor assembly 3 and is spaced apart from the rotor assembly 3.

[0021] In this embodiment, an outlet terminal 7 is fixed on a side of the circuit board 6 away from the housing, and the outlet terminal 7 is used to connect to an external power source to realize power supply.

[0022] The rotor assembly 3 includes a rotating shaft 33 and a permanent magnet 31 mounted and fixed on the rotating shaft 33; the rotating shaft 33 is rotatably connected with the front cover 4 and the bracket 5 respectively, and the permanent magnet 31 is spaced from the stator assembly 2; the rotating shaft 33 includes a rotating shaft body 331 rotatably connected with the front cover 4 and the bracket 5 respectively, and two parallel flat portions 332 formed by respectively recessing the outer peripheral side of one end of the rotating shaft body 331 close to the circuit board 6.

[0023] The sensor assembly 10 includes a sensor magnet 101 sleeved and fixed on the end of the rotating shaft 33 away from the front cover 4 and a Hall sensor 102 fixed on the side of the circuit board 6 close to the bracket 5; the Hall sensor 102 is relatively spaced from the sensor magnet 101 and is located within the magnetic field range of the sensor magnet 101; the sensor magnet 101 includes a magnet body 1011 and a fixing hole 1012 formed through the magnet body 1011; the shape of the fixing hole 1012 matches the switch at the end of the rotating shaft body 331 close to the circuit board 6, and the flat portion 332 is inserted and fixed in the fixing hole 1012. The magnetization direction of the permanent magnet 31 is perpendicular to the flat portion 332, and the magnetization direction of the sensor magnet 101 is perpendicular to the flat portion 332. By using double flat matching of the sensor magnet 101 and the rotating shaft 33, the magnetizing direction of the permanent magnet 31 is perpendicular to the flat part 332, and the rotor assembly 3 is first assembled and then magnetized; the magnetic field direction of the sensor magnet 101 is perpendicular to the flat part 332, and the design of the flat part 332 ensures the consistency of the directions of the main and secondary magnetic fields, and the mutual interference degree of the main and secondary magnetic fields tends to be consistent, which is beneficial to improving the detection and calibration accuracy of the Hall sensor and the torque performance of the motor.

[0024] In this embodiment, the fixing hole 1012 includes two oppositely disposed flat edges 10121 and two arc-shaped side walls 10122 respectively connecting the same end of the two flat edges 10121 , and the two flat portions 332 fit closely with the two flat edges 10121 .

[0025] The housing 1 is used to fix the stator assembly 2 and support the rotation of the rotor assembly 3. The mutual magnetic field generated by the stator assembly 2 and the rotor assembly 3 drives the rotor assembly 3 to rotate, thereby realizing the rotation of the entire motor.

[0026] In this embodiment, the outer periphery of the magnetic steel body 1011 forms two relatively parallel straight edges 10112 and two arc edges 10111 respectively connecting the same end of the two straight edges 10112, and the straight edges 10112 are perpendicular to the flat portion 332, so as to facilitate the assembly of the magnetic steel body 1011 and the rotating shaft 33.

[0027] In this embodiment, the housing 1 includes a housing body 11 in a hollow columnar shape, a ring-shaped connecting portion 12 formed by extending radially inwardly from one end of the housing body 11 , and a positioning hole 15 formed through the connecting portion 12 .

[0028] In this embodiment, the front cover 4 includes a front cover body 41, a first boss 42 formed by annularly extending from a side of the front cover body 41 close to the outer shell 1, a second boss 43 formed by extending from a side of the first boss 42 close to the outer shell 1, a positioning column 44 formed by protruding and extending from a side of the first boss 42 close to the outer shell 1, and a through hole 45 formed by axially penetrating the second boss 43 along the second boss 43; the side of the connecting portion 12 close to the front cover 4 abuts against the first boss 42, the inner side of the connecting portion 12 is sleeved on the outer periphery of the second boss 43, and the positioning column 44 is inserted and fixed in the positioning hole 15. The stator assembly 2 is fixed to the inner wall of the shell body 11, and the rotor assembly 3 is arranged in the through hole 45 to form a rotational connection; the first boss 42 of the front cover 4 is abutted against the end face of the shell 1, the second boss 43 is arranged in the shell 1, and the positioning column 44 is inserted into the positioning hole 15, so that the positioning column 44 and the positioning hole 15 form a fool-proof matching arrangement, thereby facilitating the assembly between the front cover 4 and the shell 1.

[0029] In this embodiment, the housing 1 further includes a plurality of limiting grooves 13 formed by the concave circumference of the other end of the housing body 11 and a limiting wall 14 formed by a protrusion extending from one side of each limiting groove 13 close to the bracket 5. The front cover 4 is fixed to the connecting portion 12, the stator assembly 2 is fixed to the inner side wall of the housing body 11, and the bracket 5 is arranged in the other end of the housing body 11 and is fixed by clamping with the limiting wall 14. The housing body 11 is used to fix and install the stator assembly 2, and the connecting portion 12 is welded and fixed to the front cover 4, so that the front cover 4 and the housing 1 are fixed as a whole.

[0030] In this embodiment, the bracket 5 includes a bracket body 51, a ring-shaped contact portion 52 formed by the bracket body 51 protruding and extending from one side of the housing 1, a limiting protrusion 53 formed by the outer peripheral side of the bracket body 51, and a avoidance groove 54 formed by the outer peripheral side of the bracket body 51; the limiting protrusion 53 and the avoidance groove 54 are distributed along the circumference of the bracket body 51, and the limiting protrusion 53 is located at the notch of the avoidance groove 54, the bracket body 51 is inserted into one end of the housing body 11 and fixed to the inner side wall of the housing body 11, the side of the contact portion 52 close to the housing body 11 abuts against the housing body 11, the limiting protrusion 53 is arranged in the limiting groove 13, and the limiting wall 14 is arranged in the avoidance groove 54. The other end of the rotor assembly 3 is supported by the bracket body 51 and forms a rotation connection. By disposing the limiting wall 14 in the avoidance groove 54 , the limiting protrusion 53 is clamped in the limiting groove 13 , thereby realizing foolproof cooperation between the limiting groove 13 and the limiting protrusion 53 .

[0031] Optionally, the limiting protrusion 53 is a limiting block or a limiting column, etc.

[0032] In this embodiment, the bracket 5 also includes at least two third bosses 55 formed by the bracket body 51 protruding and extending from one side away from the housing 1; the circuit board 6 includes a circuit board body 61 and at least two notch structures 62 formed by the circuit board body 61 being recessed at intervals, and each of the third bosses 55 is respectively arranged in one of the notch structures 62. The third bosses 55 and the notch structures 62 form a foolproof chain arrangement with each other, so that the mutual limiting effect between the bracket 5 and the circuit board 6 is good, which facilitates the outlet position of the outlet terminal 7 to be consistent with the direction of the front cover 4 and the limiting protrusion 53, and jointly realizes the unification of the motor outlet position. In this embodiment, the stator assembly 2 includes a coil winding coaxially arranged with the housing 1 and fixed to the housing 1. The coil winding can be a plurality of magnetic sheets stacked in an annular shape, and the coil winding and the rotor assembly 3 are energized to generate a magnetic field to drive the rotor assembly 3 to rotate.

[0033] In this embodiment, the brushless motor 100 further includes a first bearing 8, which is sleeved and fixed to one end of the rotating shaft 33 close to the front cover 4, and the outer periphery of the first bearing 8 is fixed in the front cover 4. The first bearing 8 reduces the friction between the rotating shaft 33 and the front cover 4, thereby improving the rotation efficiency of the rotating shaft 33.

[0034] In this embodiment, the brushless motor 100 further includes a second bearing 9, which is sleeved on one end of the rotating shaft 33 away from the front cover 4, and the outer periphery of the second bearing 9 is fixed in the bracket 5. The rotating shaft 33 is supported by the second bearing 9 and arranged in the bracket 5, so that the rotation stability of both ends of the rotating shaft 33 is good.

[0035] In this embodiment, the rotor assembly 3 further includes an iron core 32, and the iron core 32 is sleeved and fixed between the rotating shaft 33 and the permanent magnet 31. By adding the iron core 32, the magnetism of the permanent magnet 31 can be improved, thereby improving the performance of the brushless motor 100.

[0036] Compared with the prior art, in the brushless motor of the present invention, the stator assembly is fixed in the housing, the stator assembly is arranged around the rotor assembly and is spaced from the rotor assembly, so that the rotor assembly is rotatably connected to the housing; the permanent magnet and the stator assembly are spaced from each other; the rotating shaft includes a rotating shaft body that is rotatably connected to the front cover and the bracket respectively, and two mutually parallel flat parts that are respectively recessed on the outer peripheral side of one end of the rotating shaft body close to the circuit board; the sensor magnet is fixed to the rotating shaft, and the Hall sensor is fixed to the circuit board and is located within the magnetic field range of the sensor magnet; the sensor magnet includes a magnet body and a magnetic field formed by penetrating the magnet body. The fixing hole is formed by a shape matching a switch at one end of the rotating shaft body close to the circuit board, and the flat portion is inserted and fixed in the fixing hole; the magnetization direction of the permanent magnet is perpendicular to the flat portion, and the magnetization direction of the sensor magnet is perpendicular to the flat portion; in this way, the sensor magnet and the rotating shaft are matched with each other in a double flat manner, and the magnetization direction of the permanent magnet is perpendicular to the flat portion, and the rotor assembly is first assembled and then magnetized; the magnetic field direction of the sensor magnet is perpendicular to the flat portion, and the design of the flat portion ensures the consistency of the directions of the main and secondary magnetic fields, and the mutual interference degree of the main and secondary magnetic fields tends to be consistent, which is beneficial to improving the detection and calibration accuracy of the Hall sensor and the torque performance of the motor.

[0037] The above description is only an implementation mode of the present invention. It should be pointed out that, for ordinary technicians in this field, improvements can be made without departing from the creative concept of the present invention, but these all belong to the protection scope of the present invention.

Claims

1. A brushless motor, comprising a housing, a front cover and a bracket respectively mounted on both ends of the housing, a stator assembly fixed to the inner side of the housing, a rotor assembly whose two ends are respectively supported by the front cover and the bracket and are rotatably connected, a circuit board fixed to a side of the bracket away from the housing, and a sensor assembly; the stator assembly is arranged around the rotor assembly and is spaced apart from the rotor assembly; characterized in that: The rotor assembly comprises a rotating shaft and a permanent magnet sleeved and fixed on the rotating shaft; the rotating shaft is rotatably connected with the front cover and the bracket respectively, and the permanent magnet and the stator assembly are spaced apart from each other; the rotating shaft comprises a rotating shaft body rotatably connected with the front cover and the bracket respectively, and two parallel flat parts formed by respectively concavely forming the outer peripheral side of one end of the rotating shaft body close to the circuit board; The sensor assembly comprises a sensor magnet sleeved and fixed on one end of the rotating shaft away from the front cover and a Hall sensor fixed on one side of the circuit board close to the bracket; the Hall sensor is relatively spaced from the sensor magnet and is located within the magnetic field range of the sensor magnet; the sensor magnet comprises a magnet body and a fixing hole formed through the magnet body; the shape of the fixing hole matches the switch at one end of the rotating shaft body close to the circuit board, and the flat portion is inserted and fixed in the fixing hole; Wherein, the magnetization direction of the permanent magnet is perpendicular to the flat portion, and the magnetization direction of the sensor magnetic steel is perpendicular to the flat portion.

2. The brushless motor according to claim 1, characterized in that: The fixing hole comprises two flat edges arranged opposite to each other and two arc-shaped side walls respectively connecting the same end of the two flat edges, and the two flat portions are fitted to the two flat edges.

3. The brushless motor according to claim 2, characterized in that: The outer periphery of the magnetic steel body forms two relatively parallel straight edges and two arc-shaped edges respectively connecting the same ends of the two straight edges, and the straight edges are perpendicular to the flat portion.

4. The brushless motor according to claim 1, characterized in that: The shell includes a shell body in the shape of a hollow column, an annular connecting portion formed by one end of the shell body extending radially inwardly, and a positioning hole formed through the connecting portion; the front cover includes a front cover body, an annular first boss formed by a protrusion extending from a side of the front cover body close to the shell, a second boss formed by a protrusion extending from a side of the first boss close to the shell, a positioning column formed by a protrusion extending from a side of the first boss close to the shell, and a through hole that passes through the second boss along the axial direction of the second boss; the side of the connecting portion close to the front cover abuts against the first boss, the inner side of the connecting portion is sleeved on the outer periphery of the second boss, and the positioning column is inserted and fixed in the positioning hole; the stator assembly is fixed to the inner side wall of the shell body, and one end of the rotor assembly is inserted in the through hole to form a rotating connection.

5. The brushless motor according to claim 2, characterized in that: The shell also includes a plurality of limit grooves formed by the other end of the shell body being recessed along its axial direction and a limit wall formed in each of the limit grooves and protruding and extending in a direction close to the bracket; the bracket includes a bracket body, an annular contact portion formed by the side of the bracket body protruding and extending away from the shell, a limit protrusion formed by the outer peripheral side of the bracket body, and an avoidance groove formed by the outer peripheral side recessed of the bracket body, the limit protrusion and the avoidance groove are distributed along the circumference of the bracket body, and the limit protrusion is located at the notch of the avoidance groove, the bracket body is inserted into one end of the shell body and fixed to the inner side wall of the shell body, the contact portion abuts against the shell body on one side close to the shell body, the limit protrusion is arranged in the limit groove, and the limit wall is arranged in the avoidance groove; the other end of the rotor assembly is supported by the bracket body and forms a rotation connection.

6. The brushless motor according to claim 5, characterized in that: The bracket also includes at least two third bosses formed by the bracket body extending from one side away from the shell; the circuit board includes a circuit board body and at least two slot structures formed by the circuit board body being recessed at intervals, and each of the third bosses is respectively arranged in one of the slot structures.

7. The brushless motor according to claim 1, characterized in that: The stator assembly includes a coil winding coaxially disposed with the housing and fixed to the housing.

8. The brushless motor according to claim 1, characterized in that: The brushless motor further comprises a first bearing, which is sleeved and fixed on one end of the rotating shaft close to the front cover, and the outer periphery of the first bearing is fixed in the front cover.

9. The brushless motor according to claim 8, characterized in that: The brushless motor further comprises a second bearing, wherein the second bearing is sleeved on an end of the rotating shaft away from the front cover, and an outer periphery of the second bearing is fixed in the bracket.

10. The brushless motor according to claim 1, characterized in that: The rotor assembly also includes an iron core, which is sleeved and fixed between the rotating shaft and the permanent magnet.

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