CN217643116U - Brushless DC motor - Google Patents

Abstract

The application provides a brushless direct current motor, which belongs to the technical field of motors for weapons and comprises a shell assembly, wherein two ends of the shell assembly are respectively connected with a front end cover and a rear end cover assembly; one side of the rear end cover assembly, which is far away from the shell assembly, is connected with a circuit board assembly and a wiring board assembly, and an outgoing line of the circuit board assembly is connected with a Hall sensor socket; the shell assembly comprises a shell and a stator, the stator is positioned in the radial direction and the axial direction through a connecting piece between the shell and the stator, the stator comprises a winding and a stator iron core assembly located outside the winding, the winding is provided with a leading-out end and a leading-out end, the leading-out end is directly connected with the wiring board assembly, and the leading-out end is connected with a power socket. Through the processing scheme of the application, the low-voltage high-power brushless direct current motor is provided, and the reliability of electrical connection is improved.

Description

Brushless DC motor

Technical Field

The application relates to the technical field of motors for weapons, in particular to a brushless direct current motor.

Background

The brushless direct current motor is used for an electric loading mechanism of a weapon station, the mechanism is a driving mechanism of loading systems of various shells and the like, is a high-precision position servo system, and the performance of the mechanism directly influences the dynamic quality of loading speed, precision and the like. Along with the rapid development of the ground weapon industry, the electric loading gradually replaces the original mechanical loading, and the speed, the precision and the maneuverability of the electric loading are continuously increased, so that the requirements on high power, large bearing capacity, miniaturization, light weight and the like of a loading driving motor are higher and higher. At present, no motor which meets the power supply requirement of a user and has 26VDC and rated output power of not less than 2000W exists in the market, and the motor which meets the power requirement generally has the volume of 100 multiplied by 200 and the weight of not less than 8kg.

SUMMERY OF THE UTILITY MODEL

In view of this, embodiments of the present application provide a brushless dc motor for achieving high power, large load, miniaturization, and light weight of a product.

The embodiment of the application provides a brushless direct current motor, which comprises a shell assembly, wherein two ends of the shell assembly are respectively connected with a front end cover and a rear end cover assembly, a rotor assembly is arranged in the shell assembly, a connector base assembly is arranged above the shell assembly, and the connector base assembly comprises a power socket and a Hall sensor socket;

one side of the rear end cover assembly, which is far away from the shell assembly, is connected with a circuit board assembly and a wiring board assembly, an outgoing line of the circuit board assembly is connected with the Hall sensor socket, and the circuit board assembly is used for feeding back a position signal of the rotor assembly;

the casing subassembly includes casing and stator, the casing with it is right in radial and axial respectively through the connecting piece between the stator is fixed a position, the stator includes the winding and is located the stator iron core subassembly in the winding outside, the winding is equipped with and begins to draw forth end and draws forth the end, end draw forth the end with wiring board subassembly lug connection, begin to draw forth the end with supply socket connects.

According to a specific implementation mode of the embodiment of the application, the wiring board assembly comprises an insulating base, a copper bar and terminal screws, a plurality of stepped holes are uniformly distributed in the insulating base, the copper bar is located on the opening end face of each stepped hole, the heads of the terminal screws are located in the stepped holes, and the tails of the terminal screws extend out of the stepped holes;

a flat gasket, an elastic retainer ring and a nut are sequentially sleeved on the part, extending out of the stepped hole, of the binding post screw from inside to outside; and the tail end leading-out end of the winding penetrates through the rear end cover assembly and is welded into a wiring terminal after being pressed and connected, the wiring terminal is respectively electrically connected with each wiring terminal screw, and the wiring terminal is positioned between the copper bar and the flat gasket.

According to a concrete implementation of this application embodiment, the rotor subassembly includes axle and rotor core, epaxial middle part cover is equipped with first magnet steel, preceding dynamic balance ring and back dynamic balance ring, preceding dynamic balance ring with back dynamic balance ring is located respectively the both ends of first magnet steel, first magnet steel with fix a position through the rotor key between the axle, half lamination bonding is carried out through netted no latitude area in the outside of first magnet steel.

According to a concrete implementation mode of this application embodiment, lid and first wire thread insert behind the rear end cap subassembly includes rear bearing housing, casing, behind the casing lid with casing assembly's rear end is connected, rear bearing housing with lid interference fit pressure equipment behind the casing, install in the rear bearing housing and be located the rear bearing of the axle rear end of rotor subassembly, first wire thread insert is located the periphery of lid behind the casing.

According to a specific implementation manner of the embodiment of the application, the circuit board assembly is sleeved on a shaft of the rotor assembly, a sensor rotor assembly is arranged on one side, away from the rear end cover assembly, of the circuit board assembly, the sensor rotor assembly comprises a sensor base and second magnetic steel, the second magnetic steel is formed by 8N and S fan-shaped magnetic steels which are alternately and uniformly distributed and bonded on the sensor base, and epoxy glue is used for encapsulation; the sensor base is sleeved on the shaft, a key groove is formed in the middle of the sensor base, the key groove corresponding to the shaft is connected through a flat key, and the polarity of second magnetic steel on the key groove of the sensor base is the same as that of first magnetic steel of the shaft.

According to a specific implementation manner of the embodiment of the application, a wire passing groove is formed in the top of the shell and used for a wire of the winding to pass through, a shell insulating sleeve is arranged outside the wire passing groove and used for protecting the winding wire of the stator; and a second steel wire thread insert is arranged on the periphery of the shell and used for improving the bearing capacity and the fatigue strength of the threaded connection with the rear end cover assembly and the front end cover fastening screw.

According to a specific implementation mode of the embodiment of the application, the stator core assembly comprises stator punching sheets, insulating sheets and rivets, the stator punching sheets are fastened through the rivets after being laminated, and the rear end parts of the stator punching sheets are bonded with the insulating sheets;

the stator punching sheet comprises stator punching sheet grooves and rivet fastening grooves, the stator punching sheet grooves are uniformly distributed in an annular shape, and the groove shapes of the stator punching sheet grooves are in a sloping shoulder pear shape; the rivet fastening groove is used for installing the rivet and is located between the outer diameter circumferential line of the stator punching sheet and the outer circumferential line of the stator punching sheet groove.

According to a concrete implementation mode of the embodiment of the application, the connector base assembly further comprises a connector base, an upper connector cover and a rear connector cover, the upper connector cover is connected with the connector base, the power socket and the Hall sensor socket are located on the connector base, a wire fixing beam is further arranged on the connector base, and the initial leading-out end is fixed through the wire fixing beam.

According to a concrete implementation mode of the embodiment of the application, the shell and the stator are radially positioned through a stator key, and the shell and the stator are axially positioned through a set screw.

According to a specific implementation manner of the embodiment of the application, a ball bearing belleville spring is arranged between the rear bearing and the rear bearing sleeve.

Advantageous effects

Brushless DC motor in this application embodiment sets up to high-power brushless motor of low pressure, the winding of motor is equipped with and draws forth end and draws forth the end, through setting up end and drawing forth end and wiring board subassembly lug connection, can guarantee that contact resistance is not more than 0.30m omega, begin to draw forth end and supply socket lug connection, it links to each other with supply socket again with beginning to draw forth the end to have removed wire in traditional motor structure from, when guaranteeing the electric connection reliability, shorten the axial length of motor, reduce motor weight. The rotor component magnetic steel is wound and fixed by adopting a mesh weftless tape in a half-overlapping mode, so that high power, large bearing capacity, miniaturization and light weight of a product are realized.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1 is a structural diagram of a brushless dc motor according to an embodiment of the present invention;

FIG. 2 is an enlarged view taken at A in FIG. 1;

fig. 3 is a diagram of a rear end cap assembly of a brushless dc motor according to an embodiment of the present invention;

fig. 4 is a structural view of a housing assembly of a brushless dc motor according to an embodiment of the present invention;

fig. 5 is a stator structure view of a brushless dc motor according to an embodiment of the present invention;

fig. 6 is a structural view of a rotor assembly of a brushless dc motor according to an embodiment of the present invention;

fig. 7 is a block diagram of a terminal block assembly of a brushless dc motor according to an embodiment of the present invention

Fig. 8 is a structural view of a connector base assembly of a brushless dc motor according to an embodiment of the present invention.

In the figure: 1-front end cover, 2-shell assembly, 21-shell, 22-stator key, 23-stator, 231-winding, 232-insulating sheet, 233-rivet, 234-stator iron core, 24-set screw, 25-shell insulating sleeve, 26-screw, 27-second wire barrel, 3-rear end cover assembly, 31-rear bearing sleeve, 32-shell rear cover, 33-first wire barrel, 4-sensor rear cover, 5-rotor assembly, 51-shaft, 52-front dynamic balance ring, 53-reticular weftless belt, 54, rotor key, 55-first magnetic steel, 56-rear dynamic balance ring, 6-sensor rotor assembly, 7-circuit board assembly, 8-Hall sensor socket, 9-power socket, 10-connector base assembly, 101-connector base, 102-fixed line beam, 103-connector upper cover, 104-connector rear cover, 11-wiring board assembly, 111-insulating base, 112-copper bar, 113-connecting terminal, 114-flat gasket, 114-elastic retainer ring, 115-nut, 12-disc spring ball bearing.

Detailed Description

The embodiments of the present application will be described in detail below with reference to the accompanying drawings.

The following description of the embodiments of the present application is provided by way of specific examples, and other advantages and effects of the present application will be readily apparent to those skilled in the art from the disclosure herein. It should be apparent that the described embodiments are only a few embodiments of the present application, and not all embodiments. The present application is capable of other and different embodiments and its several details are capable of modifications and/or changes in various respects, all without departing from the spirit of the present application. It should be noted that the features in the following embodiments and examples may be combined with each other without conflict. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments in the present application without making any creative effort belong to the protection scope of the present application.

It is noted that various aspects of the embodiments are described below within the scope of the appended claims. It should be apparent that the aspects described herein may be embodied in a wide variety of forms and that any specific structure and/or function described herein is merely illustrative. Based on the present application, one skilled in the art should appreciate that one aspect described herein may be implemented independently of any other aspects and that two or more of these aspects may be combined in various ways. For example, an apparatus may be implemented and/or a method practiced using any number of the aspects set forth herein. In addition, such an apparatus may be implemented and/or such a method may be practiced using other structure and/or functionality in addition to or other than one or more of the aspects set forth herein.

It should be noted that the drawings provided in the following embodiments are only for illustrating the basic idea of the present application, and the drawings only show the components related to the present application rather than the number, shape and size of the components in actual implementation, and the type, amount and ratio of the components in actual implementation may be changed arbitrarily, and the layout of the components may be more complicated.

In addition, in the following description, specific details are provided to provide a thorough understanding of the examples. However, it will be understood by those skilled in the art that aspects may be practiced without these specific details.

The embodiment of the present application provides a brushless dc motor, which is a low-voltage high-power brushless dc motor, and is described in detail below with reference to the accompanying drawings.

Referring to fig. 1-2, the brushless dc motor of the present embodiment is applied to a certain type of driving mechanism, and has an input voltage of 26V and a rotation speed of 4800rpm under a load of 4 Nm. The sensor shell mainly comprises a shell component 2, wherein two ends of the shell component 2 are respectively connected with a front end cover 1 and a rear end cover component 3, one side, far away from the shell component 2, of the rear end cover component 3 is connected with a sensor rear cover 4, a rotor component 55 is arranged inside the shell component 2, a connector base component 10 is arranged above the shell component 2, and the connector base component 10 comprises a power socket 9 and a Hall sensor socket 8.

The front end cover 1 is made of stainless steel and internally provided with a rolling bearing chamber, a bearing sleeved on a shaft 51 of the rotor assembly 5 is arranged in the rolling bearing chamber, the thermal expansion coefficient of the front end cover 1 and the bearing material is close, and the influence on the service life of the motor caused by the wriggling of the outer ring of the bearing after heating is avoided.

One side that rear end cover subassembly 3 kept away from casing subassembly 2 is connected with circuit board components 7 and wiring board subassembly 11, and circuit board components 7's lead-out wire is connected with hall sensor socket 8, and circuit board components 7's effect provides the hall spare through 3 circumference equipartitions and feeds back the position signal of rotor subassembly 5 to feed back to the controller, carry out for position closed-loop control.

The housing assembly 2 comprises a housing 21 and a stator 23, the stator 23 is positioned between the housing 21 and the stator 23 in the radial direction and the axial direction respectively through a connecting piece, the stator 23 comprises a winding 231 and a stator core 234 assembly positioned outside the winding 231, the winding 231 is provided with a leading-out terminal and a trailing-out terminal, the trailing-out terminal is directly connected with the wiring board assembly 11, and the leading-out terminal is connected with the power socket 9.

The stator comprises coil, stator core 234 subassembly, refers to fig. 5, and stator core 234 subassembly includes stator punching, insulating piece 232 and rivet 233, and the stator punching is folded and is pressed the back and is fastened through rivet 233, and the rear end portion and the insulating piece 232 bonding of stator punching, when guaranteeing mechanical strength, improve the insulating nature of winding 231 and iron core. The coil is a pure copper enameled wire and is formed by connecting three-phase windings 2314 in parallel, each phase of winding 231 is provided with 4 initial leading-out terminals and 4 tail leading-out terminals, namely 12 initial leading-out terminals and 12 tail leading-out terminals in total, and all leading-out terminals are protected by using silicone sleeves.

The stator core 234 has an outer diameter of 92mm, an inner diameter of 42.2mm, and a core length of 58mm. The stator punching sheet comprises 12 stator punching sheet grooves and rivet fastening grooves, the stator punching sheet grooves are annularly and uniformly distributed, and the groove type of the stator punching sheet grooves is in a sloping shoulder pear shape; the rivet fastening groove is used for installing rivets 233, is located between the outer diameter circumferential line of the stator punching sheet and the outer circumferential line of the stator punching sheet groove, and improves structural strength after the rivets 233 penetrate and are subjected to slip riveting deformation.

In order to reduce the weight of the product, the shell 21 is made of aluminum alloy, and 40 heat dissipation teeth are uniformly arranged on the outer ring of the shell 21, so that the heat conduction of the coil heating after the stator 23 is electrified is accelerated.

In specific application, the power socket 9 is an XCD39 series large-current electrical connector resistant to salt mist and damp-heat environment, and the hall sensor socket 8 is a J599III series electrical connector resistant to salt mist and damp-heat environment. Other types of components can be selected according to actual conditions, and are not limited to those listed in the embodiment.

In one embodiment, the wiring board assembly 11 includes an insulating base 111, a copper bar 112 and a terminal screw, referring to fig. 7, the insulating base 111 is made of a glass laminated cloth plate, a plurality of stepped holes are uniformly distributed on the insulating base 111, the copper bar 112 is located on an opening end face of the stepped holes, a head of the terminal screw is located in the stepped holes and protected by epoxy glue encapsulation, the terminal screw is prevented from loosening and is insulated from the rear end cover assembly 3, and a tail of the terminal screw extends out of the stepped holes. A flat gasket 114, an elastic retainer ring 115 and a nut 116 are sequentially sleeved on the part, extending out of the stepped hole, of the binding post bolt from inside to outside; the terminal end of the winding 231 penetrates through the rear end cover assembly 3 and is welded into the wiring terminal 113 after being pressed and connected, the wiring terminal 113 is respectively electrically connected with each wiring terminal screw, and the wiring terminal 113 is positioned between the copper bar 112 and the flat gasket 114.

In this embodiment, the rotor assembly 5 is further configured, referring to fig. 6, the rotor assembly 5 includes a shaft 51 and a rotor core, a first magnetic steel 55, a front dynamic balance ring 52 and a rear dynamic balance ring 56 are sleeved on the shaft 51 at the middle position, the front dynamic balance ring 52 and the rear dynamic balance ring 56 are respectively located at two ends of the first magnetic steel 55, the first magnetic steel 55 and the shaft 51 are located through a rotor key 54, and the outer side of the first magnetic steel 55 is bonded by half-laminating through a mesh weftless tape 53. The dynamic balance rings (the front dynamic balance ring 52 and the rear dynamic balance ring 56) and the shaft 51 are welded by laser, so that the connection tightness is improved; the V-shaped groove is formed in the middle of the dynamic balance ring, so that positioning is convenient to perform during de-weighting processing.

The rotor core is formed by laminating the rotor punching sheets, and is integrally pressed with the rotor core through the rotor key 54, so that the rotor core is prevented from radially rotating. And the rotor core is provided with positioning teeth, and 8 pieces of N and S magnetic steel are uniformly and alternately bonded between the adjacent positioning teeth. The first magnetic steel 55 is bonded by half-lamination through the mesh weftless tape 53, the bonding process is not easy to loosen, the forming effect is good, and the first magnetic steel 55 can not fall off in the rotating process.

In a particular application, the shaft 51 is a stainless steel material and is heat treated to ensure that the shaft 51 has a hardness not less than HRC42.

In this embodiment, the rear end cap assembly 3 is further configured, referring to fig. 3, the rear end cap assembly 3 includes a rear bearing sleeve 31, a rear housing cap 32 and a first wire thread insert 33, the rear housing cap 32 is connected to the rear end of the housing assembly 2, the rear bearing sleeve 31 and the rear housing cap 32 are press-fitted in an interference fit manner, a rear bearing located at the rear end of the shaft 51 of the rotor assembly 5 is installed in the rear bearing sleeve 31, and the first wire thread insert 33 is located on the periphery of the rear housing cap 32.

In one embodiment, two U-shaped holes are formed in the rear cover 32 of the housing, four stepped holes are formed, and the four stepped holes are circumferentially and uniformly distributed on the insulating base 111, that is, four terminal screws are present. 12 last end on the stator draw forth the end respectively through 2U type holes of lid 32 behind the casing draw forth the back, use high temperature soldering tin welding binding post 113's mode after the first crimping, through binding post 113's round hole with respectively with 4 terminal screw of wiring board subassembly 11 carry out the electricity and be connected, use flat gasket 114, circlip 115 and nut 116 to fasten afterwards, guarantee that contact resistance is not more than 0.30m omega.

In order to reduce the weight of the product, the rear cover 32 of the housing is made of aluminum alloy, and the rear bearing sleeve 31 is made of stainless steel as a bearing chamber, so as to improve the processing precision and the mechanical strength and reduce the influence of high-temperature thermal expansion on the bearing. In the machining process, after the rear bearing sleeve 31 and the shell rear cover 32 are pressed and mounted in an interference fit mode, the shell rear cover 32 is used as a positioning device, the inner diameter of the rear bearing sleeve 31 is machined by a secondary machine, the coaxiality of the rear bearing sleeve 31 and the shell rear cover and the perpendicularity of a bearing chamber are guaranteed, and the matching precision is improved. The first wire thread insert 33 is used for improving the bearing capacity and fatigue strength of the threaded connection of the fastening screw of the rear cover of the motor.

In one embodiment, the circuit board assembly 7 is sleeved on the shaft of the rotor assembly 5, and the sensor rotor assembly 6 is arranged on one side of the circuit board assembly 7 away from the rear end cover assembly 3, referring to fig. 1, the sensor rotor assembly 6 comprises a sensor base and second magnetic steel, wherein the second magnetic steel is 8N and S sector-shaped magnetic steels which are alternately and uniformly distributed and bonded on the sensor base, and is encapsulated by epoxy glue; the sensor base is sleeved on the shaft, a key groove is formed in the middle of the sensor base and is connected with the key groove corresponding to the shaft through a flat key, and the polarity of the second magnetic steel on the key groove of the sensor base is the same as the polarity of the first magnetic steel 55 of the shaft.

In order to improve the safety and stability of the shell assembly 2, a wire passing groove is formed in the top of the shell 21 and used for allowing a wire of the winding 231 to pass through, a shell insulation sleeve 25 is arranged outside the wire passing groove and connected through a screw, a round-corner square groove is formed in the rear portion of the shell 21 and used for fixing the shell insulation sleeve 25, and the shell insulation sleeve 25 protects the wire of the winding 231 of the stator; the outer periphery of the shell 21 is provided with a second wire thread insert 27, and the second wire thread insert 27 is used for improving the bearing capacity and fatigue strength of the screw thread connection with the rear end cover component 3 and the fastening screw of the front end cover 1.

In order to make the connector base assembly 10 have a dustproof effect, the connector base assembly 10 further includes a connector base 101, and a connector upper cover 103 and a connector rear cover 104 connected to the connector base 101, referring to fig. 8, the power socket 9 and the hall sensor socket 8 are located on the connector base 101, the connector base 101 is further provided with a wire fixing beam 102, and a leading end is fixed by the wire fixing beam 102.

The contact body of the starting and leading-out end of the stator 23 and the power socket 9 adopts a high-frequency induction welding mode, so that the welding reliability is improved. The connector base 101 is made of stainless steel and plays a role in supporting the power socket 9, the hall sensor socket 8 and the wire fixing beam 102. The wire of the initial leading-out end is fixed through the wire fixing beam 102, so that the stress of the contact body of the power socket 9 is reduced, and the connection strength is improved. And finally, the connector rear cover 104 and the connector upper cover 103 are connected with the connector base through screws to protect the interior, so that the dustproof purpose is achieved. Through will begin to draw the end and directly link to each other with supply socket 9, remove from traditional motor structure, the wire links to each other with supply socket 9 again with beginning to draw the end and links to each other, when guaranteeing the electrical connection reliability, shortens the axial length of motor, reduces motor weight.

In one embodiment, the housing 21 and the stator 23 are radially positioned by the stator key 22, that is, the stator key 22 and the stator are pressed together to prevent the stator 23 from rotating radially; the housing 21 and the stator 23 are axially positioned by the set screws 24, specifically, threads are tapped on four side walls of the housing 21, and the housing is fixed by the set screws 24 at the cone ends to prevent axial looseness.

According to a concrete implementation mode of the embodiment of the application, a ball bearing belleville spring 12 is arranged between the rear bearing and the rear bearing sleeve 31 and used for increasing the bearing pretightening force, reducing self vibration and prolonging the service life of the bearing.

The rear cover of the motor is made of aluminum alloy materials, and plays a role in protecting the circuit board assembly 7, the rotor assembly 5 and the wiring board assembly 11.

The product of the embodiment of the application has the advantages that the volume is 100 multiplied by 145 and the weight is 6kg on the premise of meeting the output power by optimizing material selection, adjusting the wiring mode of the motor and the like according to the power supply requirement of the host, and the high power, the large bearing capacity, the miniaturization and the light weight of the product are realized.

The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present application should be covered within the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims (10)

1. A brushless direct current motor is characterized by comprising a shell assembly, wherein two ends of the shell assembly are respectively connected with a front end cover and a rear end cover assembly, a rotor assembly is arranged inside the shell assembly, a connector base assembly is arranged above the shell assembly, and the connector base assembly comprises a power socket and a Hall sensor socket;

one side, far away from the shell assembly, of the rear end cover assembly is connected with a circuit board assembly and a wiring board assembly, an outgoing line of the circuit board assembly is connected with the Hall sensor socket, and the circuit board assembly is used for feeding back a position signal of the rotor assembly;

the casing subassembly includes casing and stator, the casing with it is right at radial and axial respectively through the connecting piece between the stator is fixed a position, the stator includes the winding and is located the stator iron core subassembly in the winding outside, the winding is equipped with and begins to draw forth the end and draws forth the end, end draw forth the end with wiring board subassembly lug connection, begin to draw forth the end with supply socket connects.

2. The brushless direct current motor according to claim 1, wherein the terminal board assembly comprises an insulating base, a copper bar and a terminal screw, a plurality of stepped holes are uniformly distributed on the insulating base, the copper bar is located on an opening end face of the stepped holes, a head of the terminal screw is located in the stepped holes, and a tail of the terminal screw extends out of the stepped holes;

a flat gasket, an elastic retainer ring and a nut are sequentially sleeved on the part, extending out of the stepped hole, of the binding post screw from inside to outside; and the tail end leading-out end of the winding penetrates through the rear end cover assembly and is welded into a wiring terminal after being pressed and connected, the wiring terminal is respectively electrically connected with each wiring terminal screw, and the wiring terminal is positioned between the copper bar and the flat gasket.

3. The brushless direct current motor according to claim 1, wherein the rotor assembly includes a shaft and a rotor core, a first magnetic steel, a front dynamic balance ring and a rear dynamic balance ring are sleeved on a middle portion of the shaft, the front dynamic balance ring and the rear dynamic balance ring are respectively located at two ends of the first magnetic steel, the first magnetic steel and the shaft are positioned through a rotor key, and an outer side of the first magnetic steel is bonded through a mesh weftless tape in a half-laminating manner.

4. The brushless DC motor of claim 3, wherein the rear end cap assembly comprises a rear bearing sleeve, a rear housing cap, and a first wire thread sleeve, the rear housing cap is connected to the rear end of the housing assembly, the rear bearing sleeve is press-fitted to the rear housing cap in an interference fit manner, a rear bearing located at the rear end of the shaft of the rotor assembly is installed in the rear bearing sleeve, and the first wire thread sleeve is located at the periphery of the rear housing cap.

5. The brushless DC motor according to claim 3, wherein the circuit board assembly is sleeved on the shaft of the rotor assembly, a sensor rotor assembly is arranged on one side of the circuit board assembly away from the rear end cover assembly, the sensor rotor assembly comprises a sensor base and second magnetic steel, the second magnetic steel is 8N and S sector-shaped magnetic steels which are alternately and uniformly distributed and bonded on the sensor base, and the second magnetic steel is encapsulated by epoxy glue; the sensor base is sleeved on the shaft, a key groove is formed in the middle of the sensor base, the key groove corresponding to the shaft is connected through a flat key, and the polarity of second magnetic steel on the key groove of the sensor base is the same as that of first magnetic steel of the shaft.

6. The brushless direct current motor according to claim 1, wherein a wire passing groove is formed in the top of the housing, the wire passing groove is used for passing a wire of the winding, a housing insulating sleeve is arranged outside the wire passing groove, and the housing insulating sleeve protects the winding wire of the stator; the periphery of the shell is provided with a second steel wire thread insert, and the second steel wire thread insert is used for improving the bearing capacity and the fatigue strength of the threaded connection with the rear end cover assembly and the front end cover fastening screw.

7. The brushless direct current motor according to claim 1, wherein the stator core assembly includes a stator punching sheet, an insulating sheet, and a rivet, the stator punching sheet is laminated and then fastened by the rivet, and a rear end portion of the stator punching sheet is bonded to the insulating sheet;

the stator punching sheet comprises stator punching sheet grooves and rivet fastening grooves, the stator punching sheet grooves are uniformly distributed in an annular shape, and the groove type of the stator punching sheet grooves is in a sloping shoulder pear shape; the rivet fastening groove is used for installing the rivet and is located between the outer diameter circumferential line of the stator punching sheet and the outer circumferential line of the stator punching sheet groove.

8. The brushless dc motor of claim 1, wherein the connector base assembly further comprises a connector base, and an upper connector cover and a rear connector cover connected to the connector base, wherein the power socket and the hall sensor socket are located on the connector base, the connector base is further provided with a wire fixing beam, and the leading and trailing ends are fixed by the wire fixing beam.

9. The brushless dc motor of claim 1, wherein the housing is radially positioned relative to the stator by a stator key and the housing is axially positioned relative to the stator by a set screw.

10. A brushless DC motor according to claim 4, characterized in that a ball bearing belleville spring is provided between the rear bearing and the rear bearing sleeve.

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