A brushless DC motor based on closed-loop control

Abstract

The present invention discloses a brushless DC motor based on closed-loop control, comprising: a rotor assembly including a motor shaft and a heat sink, an inner rotor, and heat dissipation blades coaxially arranged on the motor shaft in sequence; a stator assembly, the stator assembly including an outer stator arranged on the periphery of the rotor assembly and a front cover and a rear cover respectively connected to the front and rear ends of the outer stator; the front cover and the rear cover are respectively provided with a first hollow portion and a second hollow portion, the heat sink and the heat dissipation blades rotate together with the motor shaft, and the external air can enter from the first hollow portion, and be discharged from the second hollow portion after passing through the gap between the outer stator and the rotor assembly. The present invention can efficiently dissipate the heat inside the motor by arranging the heat sink and the heat dissipation blades, thereby ensuring the use of the motor; the rotor assembly of the present invention can fasten the magnetic ring to the motor shaft through the front fixing member and the rear fixing member, which can greatly improve the fastening effect between the magnetic ring and the motor shaft, and can prevent the magnetic ring from loosening or falling off the motor shaft.

Description

Technical Field

[0001] The invention relates to the field of motors, and in particular to a brushless DC motor based on closed-loop control. Background Art

[0002] The brushless DC motor is composed of a motor body and a driver, and is a typical mechatronics product. A brushless motor is a motor without brushes and commutators (or collector rings), also known as a commutatorless motor. It is widely used due to its high efficiency and low noise. At present, the rotation process of brushless DC motors is controlled by closed loops, but the traditional closed-loop controlled brushless DC motors generate a lot of heat and have poor heat dissipation performance when running at high speeds, resulting in a short life of the motor. In addition, the closed-loop controlled brushless DC motor runs at high speeds, high power, and high torque, and has very high requirements for the firmness of the connection between the motor shaft and the magnetic ring on it. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide a brushless DC motor based on closed-loop control in view of the deficiencies in the above-mentioned prior art.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is: a brushless DC motor based on closed-loop control, comprising:

[0005] The rotor assembly comprises a motor shaft and a heat dissipation plate, an inner rotor and heat dissipation blades which are coaxially arranged on the motor shaft in sequence;

[0006] and a stator assembly, the stator assembly comprising an outer stator arranged at the periphery of the rotor assembly and a front end cover and a rear end cover respectively connected to the front and rear ends of the outer stator;

[0007] Among them, the front end cover and the rear end cover are respectively provided with a first hollow portion and a second hollow portion, and the heat dissipation plate and the heat dissipation fan blades rotate together with the motor shaft, so that external air can enter through the first hollow portion and be discharged from the second hollow portion after passing through the gap between the outer stator and rotor assembly.

[0008] Preferably, the heat dissipation disk comprises a disk body fixedly connected to the rear end of the motor shaft and a plurality of blades arranged in an annular shape on the front end surface of the disk body;

[0009] The blades are perpendicular to the front end surface of the disc body.

[0010] Preferably, the blade has a first blade portion located at the periphery and a second blade portion located at the inner periphery, the first blade portion is higher than the second blade portion, and the first blade portion and the second blade portion are transitionally connected via an arc portion.

[0011] Preferably, the middle part of the heat sink is provided with an axial hole and a mounting hole in sequence from front to back, and a transmission ring is fixedly connected to the rear end of the motor shaft; the transmission ring is cooperatively arranged in the mounting hole and is drivingly connected to the heat sink;

[0012] A plurality of first key slots are formed on the outer wall of the transmission ring, a plurality of first transmission keys cooperating with the first key slots are protruded from the inner wall of the mounting hole, and the outer diameter of the transmission ring is larger than the inner diameter of the shaft hole.

[0013] Preferably, the outer stator comprises a stator housing, a bracket formed inside the stator housing, a front bobbin connected to the front end of the bracket, a rear bobbin connected to the rear end of the bracket, and windings wound on the front bobbin and the rear bobbin;

[0014] The front end cover, the stator housing and the rear end cover are fixedly connected in sequence by a plurality of first screws.

[0015] Preferably, the motor shaft is connected to the front end cover and the rear end cover through a front bearing and a rear bearing respectively;

[0016] A circuit board is also arranged between the heat dissipation blades and the front end cover, and the middle of the circuit board has an opening for the motor shaft to pass through.

[0017] Preferably, a front bearing hole for accommodating the front bearing is opened in the middle of the front end cover, and a plurality of the first hollow parts are formed on the outer periphery of the front end cover;

[0018] An end cover opening is provided in the middle of the rear end cover, and an inner support ring is provided inside the end cover opening and is fixed to the inside of the end cover opening through a plurality of connecting ribs. A rear bearing hole for accommodating the rear bearing is provided in the middle of the inner support ring, and the gaps between the plurality of connecting ribs form the second hollow portion on the rear end cover. A plurality of heat dissipation holes are also provided on the outer periphery of the end cover opening.

[0019] Preferably, the inner rotor comprises a front fixing member, a magnetic ring member and a rear fixing member which are coaxially sleeved on the motor shaft in sequence from front to rear;

[0020] The magnetic ring component comprises a magnetic ring tightly sleeved with the motor shaft and a silicon steel sleeve tightly sleeved on the outer periphery of the magnetic ring;

[0021] The front fixing member includes a front fixing sleeve tightly connected to the motor shaft and a front connecting plate arranged at the rear end of the front fixing sleeve, and the rear fixing member includes a rear fixing sleeve tightly connected to the motor shaft and a rear connecting plate arranged at the front end of the rear fixing sleeve.

[0022] The front connecting plate and the rear connecting plate are both fixedly connected to the silicon steel sleeve by second screws.

[0023] Preferably, the middle portion of the motor shaft has a columnar connecting portion of the motor shaft body having a diameter larger than that of the front and rear ends thereof, and the front and rear ends of the columnar connecting portion are transitionally connected to the motor shaft body through a front cone portion and a rear cone portion respectively;

[0024] A connecting column hole for fitting and fastening the sleeve on the outer periphery of the columnar connecting part is provided in the middle of the magnetic ring, a front cone hole for fitting and fastening the sleeve on the outer periphery of the front cone part is provided in the middle of the front fixing sleeve, and a rear cone hole for fitting and fastening the sleeve on the outer periphery of the rear cone part is provided in the middle of the rear fixing sleeve.

[0025] Preferably, a dovetail groove is provided on the inner wall of the connecting column hole along its axial direction, and a dovetail key for matching with the dovetail groove is provided on the outer wall of the columnar connecting portion along its axial direction;

[0026] The outer walls of the front cone part and the rear cone part are both provided with a second transmission key, and the inner walls of the front cone hole and the rear cone hole are both provided with a second key groove matched with the second transmission key.

[0027] The beneficial effects of the present invention are as follows: the brushless DC motor based on closed-loop control of the present invention can efficiently dissipate heat inside the motor by arranging heat dissipation plates and heat dissipation blades that cooperate with each other, thereby ensuring the use of the motor; the rotor assembly of the present invention fastens the magnetic ring component to the motor shaft through front fixing parts and rear fixing parts, which can greatly improve the fastening effect between the magnetic ring component and the motor shaft, and can prevent the magnetic ring component from loosening or falling off the motor shaft. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 An exploded diagram of a brushless DC motor based on closed-loop control according to the present invention;

[0029] Figure 2 An exploded view of the brushless DC motor based on closed-loop control of the present invention from another perspective;

[0030] Figure 3 It is a schematic diagram of the overall structure of the brushless DC motor based on closed-loop control of the present invention;

[0031] Figure 4 An exploded view of a stator assembly of the present invention;

[0032] Figure 5 It is a schematic diagram of the structure of the front end cover, the stator housing and the rear end cover of the present invention;

[0033] Figure 6 It is a structural schematic diagram of the outer stator of the present invention;

[0034] Figure 7 It is a structural schematic diagram of the heat dissipation plate of the present invention;

[0035] Figure 8 It is a schematic diagram of the structure of the transmission ring and the heat dissipation plate of the present invention;

[0036] Fig. 9 It is a structural schematic diagram of the front end cover of the present invention;

[0037] Fig.10 It is a schematic diagram of the structure of the rear end cover and the circuit board of the present invention;

[0038] Fig.11 is a schematic structural diagram of a rotor assembly of the present invention;

[0039] Fig.12 An exploded view of a rotor assembly of the present invention;

[0040] Fig.13 It is a schematic cross-sectional structural diagram of the magnetic ring component of the present invention;

[0041] Fig.14 It is a cross-sectional structural schematic diagram of a brushless DC motor based on closed-loop control of the present invention;

[0042] Fig.15 It is a schematic cross-sectional structural diagram of the rotor assembly of the present invention.

[0043] Description of reference numerals:

[0044] 10—motor shaft; 100—transmission ring; 101—front bearing; 102—rear bearing; 103—motor shaft body; 104—columnar connecting portion; 105—front cone portion; 106—rear cone portion; 107—dovetail key; 108—second transmission key; 1000—first keyway;

[0045] 11—heat dissipation plate; 110—plate body; 111—axial hole; 112—mounting hole; 113—first transmission key; 114—blade; 115—first blade portion; 116—arc-shaped portion; 117—second blade portion 117; 118—heat dissipation channel;

[0046] 12—inner rotor; 120—front fixing piece; 121—magnetic ring piece; 122—rear fixing piece; 123—second screw; 1200—front fixing sleeve; 1201—front connecting plate; 1202—front tapered hole; 1210—magnetic ring; 1211—silicon steel sleeve; 1212—connecting column hole; 1213—dovetail groove; 1220—rear fixing sleeve; 1221—rear connecting plate; 1222—rear tapered hole;

[0047] 13—Cooling fan blades;

[0048] 2—stator assembly;

[0049] 20—external stator; 200—stator housing; 201—bracket; 202—front wire rack; 203—rear wire rack;

[0050] 21—front end cover; 210—first hollow portion; 211—front bearing hole;

[0051] 22—rear end cover; 220—second hollow portion; 221—end cover opening; 222—connecting ribs; 223—inner support ring; 224—rear bearing hole; 225—heat dissipation hole;

[0052] 23—first screw;

[0053] 3—circuit board; 30—opening. DETAILED DESCRIPTION

[0054] The present invention is further described in detail below in conjunction with embodiments so that those skilled in the art can implement the invention with reference to the description.

[0055] It should be understood that the terms such as “having”, “including” and “comprising” used herein do not exclude the existence or addition of one or more other elements or combinations thereof.

[0056] like Figure 1-15 As shown, a brushless DC motor based on closed-loop control in this embodiment includes:

[0057] The rotor assembly includes a motor shaft 10 and a heat sink 11, an inner rotor 12, and a heat sink blade 13 which are coaxially arranged on the motor shaft 10 in sequence;

[0058] and a stator assembly 2, the stator assembly 2 comprising an outer stator 20 disposed on the periphery of the rotor assembly and a front end cover 21 and a rear end cover 22 respectively connected to the front and rear ends of the outer stator 20;

[0059] Among them, the front end cover 21 and the rear end cover 22 are respectively provided with a first hollow portion 210 and a second hollow portion 220. The front and rear ends of the motor are non-enclosed, and there is also a gap between the stator assembly 2 and the rotor assembly. The first hollow portion 210, the gap between the stator assembly 2 and the rotor assembly, and the second hollow portion 220 form a heat dissipation channel; the heat dissipation plate 11 and the heat dissipation fan blades 13 rotate with the motor shaft 10, so that external air can enter from the first hollow portion 210, and be discharged from the second hollow portion 220 after passing through the gap between the outer stator 20 and the rotor assembly, thereby achieving good heat dissipation inside the motor.

[0060] In a preferred embodiment, referring to Figure 7The heat dissipation disk 11 includes a disk body 110 fixedly connected to the rear end of the motor shaft 10 and a plurality of blades 114 arranged in an annular shape on the front end surface of the disk body 110; the blades 114 are perpendicular to the front end surface of the disk body 110, and a heat dissipation channel 118 is formed between the blades 114. The vertically arranged blades 114 are used to discharge the air at the rear of the rear end cover 22 toward the periphery, and the flow direction of the airflow is perpendicular to the rotation direction of the blades 114, which can produce a centrifugal effect, suck out the air inside the stator assembly 2, and form a vortex effect, which can output a larger air volume in a smaller space (that is, it can reduce the heat dissipation channel required in the stator assembly 2, thereby reducing the volume of the motor), and improve the heat dissipation effect. Furthermore, the heat dissipation blades 13 at the front end of the motor shaft 10 rotate at the same time. The function of the heat dissipation blades 13 is to suck in the external air from the first hollow portion 210 of the front end cover 21 and blow it to the inside of the stator assembly 2, and then discharge it from the second hollow portion 220 of the rear end cover 22 with the internal heat. The airflow direction generated by it is the same as the airflow direction generated by the heat dissipation plate 11. The heat dissipation blades 13 can greatly increase the amount of air entering from the first hollow portion 210, and accelerate the airflow, further promoting the speed of the airflow discharged from the heat dissipation plate 11, and the heat dissipation plate 11 can increase the amount and flow rate of air discharged from the second hollow portion 220; the heat dissipation blades 13 and the heat dissipation plate 11 cooperate with each other, which can significantly increase the amount and flow rate of air, and greatly improve the heat dissipation effect. The heat dissipation blades 13 are arranged close to the circuit board 3 to fully dissipate the heat of the circuit board 3. The heat dissipation blades 13 are arranged inside the motor, making full use of the internal gap, making the structure of each mechanism compact, and helping to reduce the size of the motor.

[0061] In a further preferred embodiment, referring to Figure 7 The blade 114 has a first blade portion 115 located at the periphery and a second blade portion 117 located at the inner periphery. The height of the first blade portion 115 is higher than that of the second blade portion 117, and the first blade portion 115 and the second blade portion 117 are transitionally connected by an arc portion 116. The second blade portion 117 is low in height, so that the volume of the exhaust cavity formed between the second blade portion 117 and the rear end cover 22 is larger, which is conducive to the exhaust of the air inside the stator assembly 2 through the rear end cover 22; the first blade portion 115 is high in height, which is conducive to quickly exhausting the air in the exhaust cavity formed between the second blade portion 117 and the rear end cover 22 to the periphery. The first blade portion 115 and the second blade portion 117 are transitionally connected by an arc portion 116, and the smooth arc portion 116 can reduce the interference with the airflow and reduce the noise.

[0062] In a further preferred embodiment, referring to Figure 8, the middle part of the heat sink 11 is provided with an axial hole 111 and a mounting hole 112 in sequence from front to back, and a transmission ring 100 is fixedly connected to the rear end of the motor shaft 10; the transmission ring 100 is arranged in the mounting hole 112 and is drivingly connected to the heat sink 11; a plurality of first key slots 1000 are arranged on the outer wall of the transmission ring 100, and a plurality of first transmission keys 113 that are matched with the first key slots 1000 are protrudingly formed on the inner wall of the mounting hole 112, and the outer diameter of the transmission ring 100 is larger than the inner diameter of the axial hole 111. The transmission ring 100 can be fastened to the rear end of the motor shaft 10 by means of interference fit or glue, and the transmission ring 100 is clamped in the mounting hole 112 and fastened to the heat sink 11, so that the heat sink 11 can be conveniently and firmly fixed on the motor shaft 10, and rotate coaxially with the motor shaft 10.

[0063] Reference Figure 4 , wherein the outer stator 20 includes a stator housing 200, a bracket 201 formed inside the stator housing 200, a front bobbin 202 connected to the front end of the bracket 201, a rear bobbin 203 connected to the rear end of the bracket 201, and a winding (not shown in the figure) wound on the front bobbin 202 and the rear bobbin 203; the front bobbin 202, the rear bobbin 203, and the winding are located at the outer periphery of the inner rotor 12, and there is a gap between the front bobbin 202, the rear bobbin 203, the winding and the inner rotor 12, on the one hand to allow the inner rotor 12 to rotate under the action of the magnetic field, and on the other hand as part of the heat dissipation channel, allowing air to flow through to carry away internal heat and achieve heat dissipation.

[0064] The front end cover 21, the stator housing 200 and the rear end cover 22 are fixedly connected in sequence by a plurality of first screws 23. The outer peripheries of the front end cover 21, the stator housing 200 and the rear end cover 22 are all provided with threaded holes, through which the first screws 23 are passed and tightened in sequence.

[0065] A circuit board 3 is also arranged between the heat dissipation blades 13 and the front end cover 21 , and an opening 30 is provided in the middle of the circuit board 3 for the motor shaft 10 to pass through.

[0066] Reference Fig. 9 A front bearing hole 211 for accommodating the front bearing 101 is formed in the middle of the front end cover 21, and a plurality of first hollow portions 210 are formed on the outer periphery of the front end cover 21;

[0067] Reference Figure 5 and Fig.10The middle of the rear end cover 22 is provided with an end cover opening 221, the inner support ring 223 fixedly connected to the inner part of the end cover opening 221 through a plurality of connecting ribs 222 is provided inside the end cover opening 221, the middle of the inner support ring 223 is provided with a rear bearing hole 224 for accommodating the rear bearing 102, the gaps between the plurality of connecting ribs 222 form a second hollow portion 220 on the rear end cover 22, and the outer periphery of the end cover opening 221 is also provided with a plurality of heat dissipation holes 225. The above structure can ensure the strength of the rear end cover 22 and provide a heat dissipation channel.

[0068] Among them, the motor shaft 10 is connected to the front end cover 21 and the rear end cover 22 through the front bearing 101 and the rear bearing 102 respectively. Specifically, the inner rings of the front bearing 101 and the rear bearing 102 are fastened to the motor shaft 10, and the outer rings of the front bearing 101 and the rear bearing 102 are fastened to the inner walls of the front bearing hole 211 of the front end cover 21 and the rear bearing hole 224 of the rear end cover 22 respectively.

[0069] The front and rear ends of the motor are non-enclosed, forming a heat dissipation channel that runs through the entire motor from front to back, which can greatly improve the internal heat dissipation effect.

[0070] Reference Figure 11-15 In a preferred embodiment, the inner rotor 12 includes a front fixing member 120, a magnetic ring member 121 and a rear fixing member 122 which are coaxially sleeved on the motor shaft 10 from front to back; the magnetic ring member 121 rotates under the action of the magnetic field, thereby driving the motor shaft 10 to rotate. Force needs to be transmitted between the magnetic ring member 121 and the motor shaft 10. The size and stability of the force that can be transmitted mainly depend on the connection strength between the two.

[0071] In this embodiment, the magnetic ring member 121 includes a magnetic ring 1210 tightly sleeved with the motor shaft 10 and a silicon steel sleeve 1211 tightly sleeved on the outer periphery of the magnetic ring 1210;

[0072] The front fixing member 120 includes a front fixing sleeve 1200 which is tightly sleeved with the motor shaft 10 and a front connecting plate 1201 arranged at the rear end of the front fixing sleeve 1200. The rear fixing member 122 includes a rear fixing sleeve 1220 which is tightly sleeved with the motor shaft 10 and a rear connecting plate 1221 arranged at the front end of the rear fixing sleeve 1220. The front connecting plate 1201 and the rear connecting plate 1221 are both fixedly connected to the silicon steel sleeve 1211 by a second screw 123. The front and rear ends of the silicon steel sleeve 1211 are both provided with threaded holes, and the second screw 123 is inserted therein to fasten the silicon steel sleeve 1211 to the front connecting plate 1201 and the rear connecting plate 1221.

[0073] Among them, the magnetic ring 1210 in the magnetic ring component 121 itself is tightly sleeved with the motor shaft 10, which can achieve a certain force transmission; in addition, since the front fixing component 120 and the rear fixing component 122 are respectively fixedly connected to the front and rear ends of the motor shaft 10, and are also fixedly connected to the front and rear ends of the magnetic ring component 121 at the same time, the fastening effect between the magnetic ring component 121 and the motor shaft 10 can be greatly improved.

[0074] In a further preferred embodiment, the middle part of the motor shaft 10 has a columnar connecting portion 104 whose diameter is larger than that of the motor shaft body 103 at its front and rear ends, and the front and rear ends of the columnar connecting portion 104 are transitionally connected to the motor shaft body 103 through the front cone portion 105 and the rear cone portion 106 respectively; a connecting column hole 1212 is provided in the middle part of the magnetic ring 1210 for fitting and fastening the sleeve on the outer periphery of the columnar connecting portion 104, a front cone hole 1202 is provided in the middle part of the front fixing sleeve 1200 for fitting and fastening the sleeve on the outer periphery of the front cone portion 105, and a rear cone hole 1222 is provided in the middle part of the rear fixing sleeve 1220 for fitting and fastening the sleeve on the outer periphery of the rear cone portion 106.

[0075] The middle part of the motor shaft 10 is fastened to the magnetic ring 1210 through a columnar connecting part 104 with a larger diameter. By increasing the contact area, it can withstand greater force transmission and improve the stability of the fastening connection between the two. Furthermore, the front fixing sleeve 1200 and the rear fixing sleeve 1220 are fastened to the front cone part 105 and the rear cone part 106 on the motor shaft 10 through the front cone hole 1202 and the rear cone hole 1222. On the one hand, the cone part increases the connection area, and on the other hand, the second screw 1 The locking of the second screw 123 makes the front fixing sleeve 1200 and the rear fixing sleeve 1220 have a tendency to move toward the middle, so as to realize self-locking; that is, the second screw 123 realizes the fastening connection between the front fixing sleeve 1200, the rear fixing sleeve 1220 and the silicon steel sleeve 1211 on the one hand, and pulls the front fixing sleeve 1200 and the rear fixing sleeve 1220 toward the middle on the other hand, and realizes locking with the front cone portion 105 and the rear cone portion 106, thereby greatly improving the connection firmness between the magnetic ring 121 and the motor shaft 10. In addition, the parts of the motor shaft 10 and the magnetic ring 121 that are connected to the force are the front cone portion 105 and the rear cone portion 106 and the columnar connecting portion 104 with a larger diameter. The front cone portion 105, the rear cone portion 106 and the columnar connecting portion 104 can disperse the force to a larger area, thereby increasing the magnitude of the force that the motor shaft 10 can withstand. In the conventional solution, the magnetic ring 1210 is usually directly connected to the motor shaft 10 by glue, and this connection method is not strong enough, especially after long-term use, it is easy to cause the connection force to decrease, affecting the transmission effect. In this embodiment, the above structure can greatly improve the connection strength between the magnetic ring 1210 and the motor shaft 10 without damaging the strength of the motor shaft 10.

[0076] In a further preferred embodiment, a dovetail groove 1213 (with a dovetail-shaped cross section) is provided on the inner wall of the connecting column hole 1212 along its axial direction, and a dovetail key 107 (with a dovetail-shaped cross section) for matching in the dovetail groove 1213 is provided on the outer wall of the columnar connecting portion 104 along its axial direction; a second transmission key 108 is provided on the outer wall of the front cone portion 105 and the rear cone portion 106, and a second keyway matching with the second transmission key 108 is provided on the inner wall of the front cone hole 1202 and the rear cone hole 1222. The matching of the dovetail key 107 and the dovetail groove 1213 can further improve the transmission stability and connection strength between the columnar connecting portion 104 and the magnetic ring 1210; the matching of the second transmission key 108 and the second keyway can improve the connection strength and transmission stability between the front cone portion 105, the rear cone portion 106 and the front fixing sleeve 1200, the rear fixing sleeve 1220.

[0077] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to specific details.

Claims

1. A brushless DC motor based on closed-loop control, characterized in that: include: The rotor assembly comprises a motor shaft and a heat dissipation plate, an inner rotor and heat dissipation blades which are coaxially arranged on the motor shaft in sequence; and a stator assembly, the stator assembly comprising an outer stator arranged at the periphery of the rotor assembly and a front end cover and a rear end cover respectively connected to the front and rear ends of the outer stator; The front cover and the rear cover are respectively provided with a first hollow portion and a second hollow portion, and the heat dissipation plate and the heat dissipation fan blade rotate together with the motor shaft, so that external air can enter through the first hollow portion and be discharged from the second hollow portion after passing through the gap between the outer stator and the rotor assembly; The heat dissipation plate comprises a plate body fixedly connected to the rear end of the motor shaft and a plurality of blades arranged in an annular shape on the front end surface of the plate body; the blades are perpendicular to the front end surface of the plate body; The inner rotor comprises a front fixing member, a magnetic ring member and a rear fixing member coaxially sleeved on the motor shaft from front to back in sequence; the magnetic ring member comprises a magnetic ring tightly sleeved with the motor shaft and a silicon steel sleeve tightly sleeved on the outer periphery of the magnetic ring; the front fixing member comprises a front fixing sleeve tightly sleeved with the motor shaft and a front connecting plate arranged at the rear end of the front fixing sleeve, and the rear fixing member comprises a rear fixing sleeve tightly sleeved with the motor shaft and a rear connecting plate arranged at the front end of the rear fixing sleeve; the front connecting plate and the rear connecting plate are both fixedly connected to the silicon steel sleeve by a second screw; The middle part of the motor shaft has a columnar connecting part with a diameter larger than that of the motor shaft body at its front and rear ends, and the front and rear ends of the columnar connecting part are transitionally connected with the motor shaft body through the front cone part and the rear cone part respectively; the middle part of the magnetic ring is provided with a connecting column hole for matching and fastening the sleeve on the outer periphery of the columnar connecting part, the middle part of the front fixing sleeve is provided with a front cone hole for matching and fastening the sleeve on the outer periphery of the front cone part, and the middle part of the rear fixing sleeve is provided with a rear cone hole for matching and fastening the sleeve on the outer periphery of the rear cone part; A dovetail groove is provided on the inner wall of the connecting column hole along its axial direction, and a dovetail key for matching with the dovetail groove is provided on the outer wall of the columnar connecting portion along its axial direction; The outer walls of the front cone part and the rear cone part are both provided with a second transmission key, and the inner walls of the front cone hole and the rear cone hole are both provided with a second key groove matched with the second transmission key.

2. The brushless DC motor based on closed-loop control according to claim 1, characterized in that: The blade comprises a first blade portion at the periphery and a second blade portion at the inner periphery, the first blade portion is higher than the second blade portion, and the first blade portion and the second blade portion are transitionally connected via an arc portion.

3. The brushless DC motor based on closed-loop control according to claim 2, characterized in that: The middle part of the heat sink is provided with an axial hole and a mounting hole in sequence from front to back, and a transmission ring is fixedly connected to the rear end of the motor shaft; the transmission ring is cooperatively arranged in the mounting hole and is drivingly connected to the heat sink; A plurality of first key slots are formed on the outer wall of the transmission ring, a plurality of first transmission keys cooperating with the first key slots are protruded from the inner wall of the mounting hole, and the outer diameter of the transmission ring is larger than the inner diameter of the shaft hole.

4. The brushless DC motor based on closed-loop control according to claim 1, characterized in that: The outer stator comprises a stator housing, a bracket formed inside the stator housing, a front bobbin connected to the front end of the bracket, a rear bobbin connected to the rear end of the bracket, and windings wound on the front bobbin and the rear bobbin; The front end cover, the stator housing and the rear end cover are fixedly connected in sequence by a plurality of first screws.

5. The brushless DC motor based on closed-loop control according to claim 1, characterized in that: The motor shaft is connected to the front end cover and the rear end cover through a front bearing and a rear bearing respectively; A circuit board is also arranged between the heat dissipation blades and the front end cover, and the middle of the circuit board has an opening for the motor shaft to pass through.

6. The brushless DC motor based on closed-loop control according to claim 5, characterized in that: A front bearing hole for accommodating the front bearing is formed in the middle of the front end cover, and a plurality of the first hollow parts are formed on the outer periphery of the front end cover; An end cover opening is provided in the middle of the rear end cover, and an inner support ring is provided inside the end cover opening and is fixed to the inside of the end cover opening through a plurality of connecting ribs. A rear bearing hole for accommodating the rear bearing is provided in the middle of the inner support ring, and the gaps between the plurality of connecting ribs form the second hollow portion on the rear end cover. A plurality of heat dissipation holes are also provided on the outer periphery of the end cover opening.

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