A brushless DC motor with smooth speed regulation

Abstract

The present invention discloses a brushless DC motor with smooth speed regulation, comprising: a stator assembly including a base, a wire bracket fixed on the base, and windings arranged on the wire bracket; a rotor assembly including a motor shaft rotatably inserted into the base at the rear end, a connection end cover fixedly sleeved on the front part of the motor shaft, a magnetic sheet bracket arranged around the periphery of the wire bracket and fixedly connected to the rear end of the connection end cover, a fixed pressure ring fixedly connected to the rear end of the magnetic sheet bracket, and a plurality of magnetic steel sheets arranged on the magnetic sheet bracket and arranged around the wire bracket. The brushless DC motor with smooth speed regulation of the present invention tightly connects the connection end cover and the motor shaft through a front fixing member and a rear fixing member, and has high connection strength and stability; the motor of the present invention has an axial heat dissipation channel, and the heat dissipation effect is good; in the present invention, by providing a T-shaped mounting groove, a card slot, a card strip, etc., the connection strength between the magnetic steel sheet and the magnetic sheet bracket is very high.

Description

Technical Field

[0001] The present invention relates to the field of motors, and particularly to a brushless DC motor with smooth speed regulation. Background Art

[0002] A brushless DC motor consists of a motor main body and a driver, and is a typical mechatronic product. A brushless motor refers to a motor without a brush and a commutator (or slip ring), also known as a non-commutator motor. It is widely used due to its high working efficiency, low noise, etc. According to the different positions of the stator and the rotor, it is divided into an inner-rotor brushless DC motor and an outer-rotor brushless DC motor. The outer-rotor motor has a higher volume ratio and better speed regulation performance. The outer-rotor brushless DC motor is widely used, such as Patent 201920257055.9. However, in this motor, the connection strength between the rotor structure and the rotating shaft is insufficient, and in addition, it lacks a heat dissipation structure, resulting in poor heat dissipation effect. In a brushless DC motor with smooth speed regulation, a ring-shaped bracket is usually used to install the magnetic steel sheets, which are arranged annularly on the outer periphery of the stator, so as to drive the magnetic steel sheets and the bracket to rotate through the magnetic field of the stator to achieve the rotation of the rotor. The magnetic steel sheets and the bracket are usually connected by glue, and their connection strength has a great impact on the performance of the motor. For example, Patent 201220161855.9 discloses a magnetic steel sheet fixing bracket. Among them, after the magnetic steel sheet is inserted into the placement groove of the fixing bracket, it is connected by glue, but its connection strength is prone to be insufficient.

[0003] Therefore, a more reliable solution is needed now. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a brushless DC motor with smooth speed regulation for the deficiencies in the above-mentioned prior art.

[0005] To solve the above technical problem, the technical solution adopted by the present invention is: A brushless DC motor with smooth speed regulation, comprising:

[0006] A stator assembly, which includes a base, a wire bracket fixedly connected to the base, and windings arranged on the wire bracket;

[0007] And a rotor assembly, which includes a motor shaft rotatably inserted into the base at the rear end, a connection end cover fixedly sleeved on the front part of the motor shaft, a magnetic sheet bracket surrounding the periphery of the wire bracket and fixedly connected to the rear end of the connection end cover, a fixed pressing ring fixedly connected to the rear end of the magnetic sheet bracket, and a plurality of magnetic steel sheets arranged on the magnetic sheet bracket and surrounding the wire bracket;

[0008] Wherein, front and rear fixing members fixedly sleeved on the motor shaft are respectively arranged at the front and rear ends of the connection end cover, and the front fixing member, the connection end cover, and the rear fixing member are fixedly connected in sequence by a first screw.

[0009] Preferably, the front fixing member includes a front fixing sleeve tightly sleeved on the motor shaft and a front connecting plate provided at the rear end of the front fixing sleeve, and the rear fixing member includes a rear fixing sleeve tightly sleeved on the motor shaft and a rear connecting plate provided at the front end of the rear fixing sleeve;

[0010] First threaded holes for mating with the first screws are formed in the front connecting plate, the connecting end cover and the rear connecting plate, and a first nut is further sleeved on the end of the first screw.

[0011] Preferably, a columnar connecting portion with a diameter larger than that of the motor shaft body at the front and rear ends is provided in the middle of the motor shaft, and the front and rear ends of the columnar connecting portion are respectively connected to the motor shaft body through a front tapered portion and a rear tapered portion;

[0012] A connecting column hole for tightly sleeving on the outer periphery of the columnar connecting portion is formed in the middle of the connecting end cover, a front tapered hole for tightly sleeving on the outer periphery of the front tapered portion is formed in the middle of the front fixing sleeve, and a rear tapered hole for tightly sleeving on the outer periphery of the rear tapered portion is formed in the middle of the rear fixing sleeve.

[0013] Preferably, a dovetail groove is axially formed in the inner wall of the connecting column hole, and a dovetail key for being arranged in the dovetail groove in a matching manner is axially formed on the outer wall of the columnar connecting portion;

[0014] Drive keys are arranged on the outer walls of the front tapered portion and the rear tapered portion, and key grooves for mating with the drive keys are formed in the inner walls of the front tapered hole and the rear tapered hole.

[0015] Preferably, second threaded holes are formed in the outer periphery of the connecting end cover, the magnetic sheet bracket and the fixing pressing ring, and the connecting end cover, the magnetic sheet bracket and the fixing pressing ring are sequentially fixed through second screws inserted into the second threaded holes in a matching manner, and a second nut is further sleeved on the rear end of the second screw;

[0016] A fan-shaped heat dissipation opening is formed in the connecting end cover;

[0017] The base includes a bearing sleeve and a flange plate fixed at the rear end of the bearing sleeve, the wire bracket is fixed to the flange plate through a third screw, and two bearings are arranged between the rear end of the motor shaft and the bearing sleeve.

[0018] Preferably, the magnetic sheet bracket includes an annular body and a magnetic sheet groove formed in the inner wall of the annular body for fitting and installing the magnetic steel sheet, the rear end of the magnetic sheet groove penetrates through to the rear end face of the annular body, and the front end of the magnetic sheet groove does not penetrate through the annular body; the fixing pressing ring is used for pressing the rear end face of the magnetic steel sheet inserted into the magnetic sheet groove;

[0019] A plurality of heat dissipation holes are formed at positions on the annular body between the magnetic sheet grooves.

[0020] Preferably, the magnetic sheet groove is T-shaped in a cross-section parallel to the radial direction of the annular body. The magnetic sheet groove includes a through groove with a width smaller than that of the magnetic steel sheet and a mounting groove with a width larger than that of the through groove, which are sequentially arranged from the inner wall of the annular body towards the inside. The magnetic steel sheet is fitted and inserted into the mounting groove.

[0021] Preferably, a plurality of clamping strips are fixedly connected to the back surface of the magnetic steel sheet in contact with the inner wall of the back of the mounting groove, and the length direction of the clamping strips is parallel to the axial direction of the annular body;

[0022] A clamping groove for the clamping strip to be fitted and clamped into is formed on the inner wall of the back of the mounting groove;

[0023] The cross-sections of the clamping strip and the clamping groove are both trapezoidal in reverse.

[0024] Preferably, an arc-shaped elastic sheet is further fixedly connected to the inner wall of the front part of the mounting groove.

[0025] Preferably, glue injection holes are formed through the clamping strip along its length direction, and glue outlet holes communicating with the glue injection holes are formed on the side surfaces of the clamping strip not in contact with the magnetic steel sheet.

[0026] The beneficial effects of the present invention are as follows: The brushless DC motor with smooth speed regulation of the present invention tightly connects the connection end cover and the motor shaft through the front fixing member and the rear fixing member, having high connection strength and stability; the motor of the present invention has an axial heat dissipation channel with good heat dissipation effect; by setting a T-shaped mounting groove, a clamping groove, a clamping strip, etc. in the present invention, the connection strength between the magnetic steel sheet and the magnetic sheet bracket is high. Description of the Drawings

[0027] Figure 1 is an exploded view of the brushless DC motor with smooth speed regulation of the present invention;

[0028] Figure 2 is a schematic diagram of the overall structure of the brushless DC motor with smooth speed regulation of the present invention;

[0029] Figure 3 is an exploded view of the rotor assembly of the present invention;

[0030] Figure 4 is a schematic diagram of the overall structure of the rotor assembly of the present invention;

[0031] Figure 5 is a schematic cross-sectional view of the brushless DC motor with smooth speed regulation of the present invention;

[0032] Figure 6Schematic cross-sectional structure diagram of the rotor assembly of the present invention;

[0033] Figure 7 Front view of the front end face of the brushless DC motor with smooth speed regulation of the present invention;

[0034] Figure 8 Front view of the connection end cover of the present invention;

[0035] Figure 9 Schematic structure diagram of the fixed pressure ring of the present invention;

[0036] Figure 10 Schematic structure diagram of the magnetic steel sheet of the present invention;

[0037] Figure 11 Side view of the magnetic steel sheet of the present invention;

[0038] Figure 12 Schematic cross-sectional structure diagram of a partial view of the magnetic sheet bracket in an embodiment of the present invention;

[0039] Figure 13 Schematic cross-sectional structure diagram of a partial view of the magnetic sheet bracket in another embodiment of the present invention;

[0040] Figure 14 Schematic structure diagram of the arc-shaped elastic sheet in an embodiment of the present invention.

[0041] Explanation of reference numerals:

[0042] 1 - Stator assembly; 10 - Base; 11 - Wire bracket; 12 - Bearing sleeve; 13 - Flange; 14 - Bearing;

[0043] 2 - Rotor assembly; 20 - Motor shaft; 21 - Connection end cover; 22 - Magnetic sheet bracket; 23 - Fixed pressure ring; 24 - Magnetic steel sheet; 25 - Front fixing piece; 26 - Rear fixing piece; 27 - Keyway; 200 - Columnar connection part; 201 - Motor shaft body; 202 - Front cone part; 203 - Rear cone part; 204 - Dovetail key; 205 - Transmission key; 210 - Connection column hole; 211 - Dovetail groove; 212 - Sector-shaped heat dissipation opening; 220 - Ring-shaped body; 221 - Magnetic sheet groove; 222 - Through groove; 223 - Installation groove; 224 - Card slot; 225 - Arc-shaped elastic sheet; 226 - Heat dissipation hole; 240 - Card strip; 241 - Glue injection hole; 242 - Glue outlet hole; 250 - Front fixing sleeve; 251 - Front connection plate; 252 - Front cone hole; 260 - Rear fixing sleeve; 261 - Rear connection plate; 262 - Rear cone hole;

[0044] 30 - First threaded hole; 31 - First screw; 32 - First nut; 33 - Second threaded hole; 34 - Second screw; 35 - Second nut; 36 - Third screw. Detailed implementation manners

[0045] The present invention will be further described in detail below in conjunction with embodiments, so that those skilled in the art can implement it with reference to the text of the specification.

[0046] It should be understood that terms such as "having", "comprising", and "including" used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0047] As Figures 1-14 shown, a brushless DC motor with smooth speed regulation in this embodiment includes:

[0048] A stator assembly 1, which includes a base 10, a wire bracket 11 fixedly connected to the base 10, and windings (not shown in the figure) arranged on the wire bracket 11;

[0049] And a rotor assembly 2, which includes a motor shaft 20 rotatably inserted into the base 10 at the rear end, a connection end cover 21 fixedly sleeved on the front part of the motor shaft 20, a magnetic sheet bracket 22 arranged around the periphery of the wire bracket 11 and fixedly connected to the rear end of the connection end cover 21, a fixed pressure ring 23 fixedly connected to the rear end of the magnetic sheet bracket 22, and a plurality of magnetic steel sheets 24 arranged on the magnetic sheet bracket 22 and surrounding the wire bracket 11;

[0050] Wherein, a front fixing member 25 and a rear fixing member 26 fixedly sleeved on the motor shaft 20 are respectively arranged at the front and rear ends of the connection end cover 21, and the front fixing member 25, the connection end cover 21, and the rear fixing member 26 are sequentially fixedly connected by a first screw 31.

[0051] The magnetic steel sheet 24 is fixedly connected to the magnetic sheet bracket 22, and the magnetic steel sheet 24 rotates under the action of the magnetic field, thereby driving the magnetic sheet bracket 22 to rotate, and driving the connection end cover 21 and the motor shaft 20 to rotate through the magnetic sheet bracket 22.

[0052] Force transmission is required between the connection end cover 21 and the motor shaft 20, and the magnitude and stability of the torque that can be transmitted mainly depend on the connection strength between the two.

[0053] In one embodiment, referring to Figures 3-6 , the front fixing member 25 includes a front fixing sleeve 250 tightly sleeved on the motor shaft 20 and a front connection disk 251 arranged at the rear end of the front fixing sleeve 250, and the rear fixing member 26 includes a rear fixing sleeve 260 tightly sleeved on the motor shaft 20 and a rear connection disk 261 arranged at the front end of the rear fixing sleeve 260;

[0054] First threaded holes 30 matching the first screw 31 are respectively opened on the front connection disk 251, the connection end cover 21, and the rear connection disk 261, and a first nut 32 is further sleeved on the end of the first screw 31.

[0055] The middle part of the motor shaft 20 has a columnar connecting part 200 with a diameter larger than that of the motor shaft body 201 at its front and rear ends. The front and rear ends of the columnar connecting part 200 are transitionally connected to the motor shaft body 201 through a front conical part 202 and a rear conical part 203 respectively;

[0056] A connecting column hole 210 for tightly sleeving on the outer periphery of the columnar connecting part 200 in a matching manner is provided in the middle of the connecting end cover 21. A front conical hole 252 for tightly sleeving on the outer periphery of the front conical part 202 in a matching manner is provided in the middle of the front fixing sleeve 250. A rear conical hole 262 for tightly sleeving on the outer periphery of the rear conical part 203 in a matching manner is provided in the middle of the rear fixing sleeve 260.

[0057] A dovetail groove 211 is axially provided on the inner wall of the connecting column hole 210. A dovetail key 204 for being arranged in the dovetail groove 211 in a matching manner is axially provided on the outer wall of the columnar connecting part 200;

[0058] Driving keys 205 are provided on the outer walls of the front conical part 202 and the rear conical part 203. Key grooves 27 for cooperating with the driving keys 205 are provided on the inner walls of the front conical hole 252 and the rear conical hole 262.

[0059] In this embodiment, the columnar connecting part 200 of the motor shaft 20 is tightly inserted into the connecting column hole 210, and the driving connection is realized through the cooperation of the dovetail groove 211 and the dovetail key 204. Further, the columnar connecting part 200 and the connecting column hole 210 are also bonded with glue to increase the connection strength.

[0060] In this embodiment, the middle part of the motor shaft 20 is fixedly connected to the connecting end cover 21 through a columnar connecting part 200 with a larger diameter. By increasing the contact area, it can withstand a greater force transmission and improve the stability of the fixed connection between the two. Further, the front fixing sleeve 250 and the rear fixing sleeve 260 are fixedly sleeved on the front conical part 202 and the rear conical part 203 on the motor shaft 20 through the front conical hole 252 and the rear conical hole 262. On the one hand, the conical part increases the connection area, and on the other hand, through the locking of the first screw 31, the front fixing sleeve 250 and the rear fixing sleeve 260 have a tendency to move closer to the middle, realizing self-locking. That is, the first screw 31 realizes the fixed connection between the front fixing sleeve 250, the rear fixing sleeve 260 and the connecting end cover 21 on the one hand, and pulls the front fixing sleeve 250 and the rear fixing sleeve 260 towards the middle on the other hand, realizing locking with the front conical part 202 and the rear conical part 203, thereby greatly improving the connection firmness between the connecting end cover 21 and the motor shaft 20. In addition, the parts of the motor shaft 20 and the connecting end cover 21 that are connected and stressed are the front conical part 202, the rear conical part 203 and the columnar connecting part 200 with a larger diameter. The front conical part 202, the rear conical part 203 and the columnar connecting part 200 can disperse the stress to a larger area, thereby improving the magnitude of the force that the motor shaft 20 can withstand. In the traditional solution of realizing drive connection only through glue or the transmission key 205, the connection firmness is insufficient. Especially after long-term use, it is easy to cause the connection force to decrease and affect the transmission effect. In this embodiment, through the cooperation of the above-mentioned connection structures, the connection firmness between the connecting end cover 21 and the motor shaft 20 can be greatly improved, and the strength of the motor shaft 20 will not be damaged.

[0061] In a further preferred embodiment, a dovetail groove 211 (with a dovetail-shaped cross-section) is axially formed on the inner wall of the connecting shaft hole, and a dovetail key 204 (with a dovetail-shaped cross-section) for being arranged in the dovetail groove 211 is axially formed on the outer wall of the columnar connecting part 200; transmission keys 205 are arranged on the outer walls of the front conical part 202 and the rear conical part 203, and key grooves 27 for cooperating with the transmission keys 205 are formed on the inner walls of the front conical hole 252 and the rear conical hole 262. The cooperation between the dovetail key 204 and the dovetail groove 211 can further improve the transmission stability and connection strength between the columnar connecting part 200 and the connecting end cover 21; the cooperation between the transmission keys 205 and the key grooves 27 can further improve the connection strength and transmission stability between the front conical part 202, the rear conical part 203 and the front fixing sleeve 250, the rear fixing sleeve 260.

[0062] In one embodiment, referring to Figures 7-9 , second threaded holes 33 are formed on the outer perimeters of the connecting end cover 21, the magnetic sheet bracket 22 and the fixing retaining ring 23. The connecting end cover 21, the magnetic sheet bracket 22 and the fixing retaining ring 23 are sequentially fixed through second screws 34 that are inserted into the second threaded holes 33 in a matching manner. A second nut 35 is also sleeved on the rear end of the second screw 34;

[0063] The base 10 includes a bearing sleeve 12 and a flange 13 fixedly connected to the rear end of the bearing sleeve 12. The wire bracket 11 is fixedly connected to the flange 13 by a third screw 36. There are two bearings 14 provided between the rear end of the motor shaft 20 and the bearing sleeve 12. The inner ring of the bearing 14 is fixedly connected to the motor shaft 20, and the outer ring is fixedly connected to the bearing sleeve 12. The magnet sheet bracket 22 is made of a non-magnetic material, such as a non-magnetic plastic material.

[0064] Among them, the magnet sheet bracket 22 includes an annular body 220 and a magnet sheet groove opened on the inner wall of the annular body 220 for fitting and installing the magnet steel sheet 24. The rear end of the magnet sheet groove penetrates through to the rear end face of the annular body 220, and the front end of the magnet sheet groove does not penetrate through the annular body 220; the fixed pressing ring 23 is used to press against the rear end face of the magnet steel sheet 24 inserted in the magnet sheet groove; the magnet steel sheet 24 is installed in the magnet sheet groove and fixed by glue, so as to drive the magnet sheet bracket 22 to rotate by using the magnet steel sheet 24.

[0065] The connecting end cover 21 is provided with a fan-shaped heat dissipation opening 212; a plurality of heat dissipation holes 226 are opened at positions on the annular body 220 between the magnet sheet grooves. In the brushless DC motor with smooth speed regulation of this embodiment, the rear end of the wire bracket 11 is in an open state, and the setting of the fan-shaped heat dissipation opening 212 on the connecting end enables the whole motor to have an axially through heat dissipation channel, having excellent heat dissipation effect. In addition, when the annular body 220 rotates, radial air circulation is generated through the heat dissipation holes 226, and the heat dissipation holes 226 provide a radial heat dissipation channel, further improving the heat dissipation effect.

[0066] In a further preferred embodiment, referring to Figures 10-12 , the magnet sheet groove is T-shaped in a cross-section parallel to the radial direction of the annular body 220. The magnet sheet groove includes a through groove 222 with a width smaller than that of the magnet steel sheet 24 and an installation groove 223 with a width larger than that of the through groove 222, which are sequentially arranged from the inner wall of the annular body 220 towards the inside. The magnet steel sheet 24 is fitted and inserted into the installation groove 223.

[0067] The magnet steel sheet 24 is fitted and inserted into the installation groove 223, and most of the inner end face of the magnet steel sheet 24 is exposed through the through groove 222 to receive the magnetic field force generated by the winding. The magnet steel sheet 24 is clamped in the installation groove 223 and restricted by the inner wall of the installation groove 223, and then bonded by glue, so that the connection strength between the magnet steel sheet 24 and the magnet sheet bracket 22 is significantly enhanced, ensuring the transmission of torque; the fixed pressing ring 23 then presses the magnet steel sheet 24 from the rear end, so that the magnet steel sheet 24 is stressed in all directions and fastened in the installation groove 223, which can improve the connection stability between the magnet steel sheet 24 and the magnet sheet bracket 22.

[0068] On the back of the magnetic steel sheet 24 that contacts the inner wall of the back of the installation groove 223, a plurality of clamping strips 240 are fixedly connected, and the length direction of the clamping strips 240 is parallel to the axial direction of the annular body 220; on the inner wall of the back of the installation groove 223, a clamping groove 224 is provided for the clamping strips 240 to be fitted and inserted.

[0069] Further, the cross-sections of the clamping strips 240 and the clamping grooves 224 are both trapezoidal in reverse. That is, the width of the back surface of the clamping strip 240 is greater than the width of the front end surface. The clamping strip 240 and the clamping groove 224 are dimensionally matched, preferably with a certain interference fit. The clamping strip 240 is fitted and inserted into the clamping groove 224, which can improve the connection strength between the magnetic steel sheet 24 and the magnetic sheet bracket 22. The advantage of the reverse trapezoidal structure is that when the motor is working, due to thermal expansion, and the clamping strip 240 is closer to the winding and has a higher temperature, the expansion of the clamping strip 240 will be more obvious than that of the clamping groove 224. The cooperation of the reverse trapezoidal structure causes the clamping groove 224 to produce a pulling effect on the clamping strip 240, thereby further improving the connection strength between the two.

[0070] In a further preferred embodiment, referring to Figure 13 、 Figure 14 , an arc-shaped elastic piece 225 is also fixedly connected to the inner wall of the front part of the installation groove 223. When the magnetic steel sheet 24 is inserted into the installation groove 223, the arc-shaped elastic piece 225 is squeezed. After being inserted in place, the arc-shaped elastic piece 225 has an outward extrusion force on the magnetic steel sheet 24, so that the magnetic steel sheet 24 is closely attached to the inner wall of the installation groove 223, and then bonded with glue; by providing a pre-tightening force through the arc-shaped elastic piece 225, the magnetic steel sheet 24 is closely attached to the inner wall of the installation groove 223, which is beneficial to the firm bonding between the magnetic steel sheet 24 and the inner wall of the installation groove (the side area of the magnetic steel sheet 24 is small, and the contact area between the front end surface and the inner wall of the front part of the installation groove 223 is also small, so the magnetic steel sheet 24 mainly provides a bonding surface for connecting with the installation groove 223 through its back surface), which can improve the connection strength and stability.

[0071] In a further preferred embodiment, referring to Figure 10 、 Figure 11 , a glue injection hole 241 is provided through the clamping strip 240 along its length direction, and glue outlet holes 242 communicated with the glue injection hole 241 are provided on the sides of the clamping strip 240 that do not contact the magnetic steel sheet 24. Glue is pre-coated on the magnetic steel sheet 24 or the inner wall of the installation groove 223, and then the magnetic steel sheet 24 is inserted into the installation groove 223 so that the two are bonded with glue. In this embodiment, further, glue is injected into the clamping strip 240 through the glue injection hole 241, and then enters between the clamping strip 240 and the clamping groove 224 through the glue outlet holes 242. The glue can also flow into the gap between the back surface of the magnetic steel sheet 24 and the inner wall of the front part of the installation groove 223 through the gap between the clamping strip 240 and the clamping groove 224, so that the glue fully fills between the two connection surfaces, further improving the bonding strength, and thus improving the connection strength between the magnetic steel sheet 24 and the magnetic sheet bracket 22.

[0072] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and embodiments. It can be fully applied to various fields suitable for the present invention. For those familiar with the field, additional modifications can be easily achieved. Therefore, without departing from the general concept defined by the claims and the equivalent scope, the present invention is not limited to specific details.

Claims

1. A brushless DC motor with smooth speed regulation, characterized in that, Comprising: A stator assembly, which includes a base, a wire bracket fixedly connected to the base, and windings arranged on the wire bracket; And a rotor assembly, which includes a motor shaft whose rear end is rotatably inserted into the base, a connection end cover fixedly sleeved on the front part of the motor shaft, a magnetic sheet bracket arranged around the periphery of the wire bracket and fixedly connected to the rear end of the connection end cover, a fixed pressing ring fixedly connected to the rear end of the magnetic sheet bracket, and a plurality of magnetic steel sheets arranged on the magnetic sheet bracket and surrounding the wire bracket; Wherein, front and rear fixing parts fixedly sleeved on the motor shaft are respectively arranged at the front and rear ends of the connection end cover, and the front fixing part, the connection end cover, and the rear fixing part are sequentially fixedly connected by a first screw; The front fixing part includes a front fixing sleeve tightly sleeved on the motor shaft and a front connection disk arranged at the rear end of the front fixing sleeve, and the rear fixing part includes a rear fixing sleeve tightly sleeved on the motor shaft and a rear connection disk arranged at the front end of the rear fixing sleeve; first threaded holes for cooperating with the first screw are opened on the front connection disk, the connection end cover, and the rear connection disk, and a first nut is further sleeved on the end of the first screw; a columnar connection part with a diameter larger than that of the motor shaft body at the front and rear ends is provided in the middle of the motor shaft, and the front and rear ends of the columnar connection part and the motor shaft body are respectively connected by a front tapered part and a rear tapered part; a connection column hole for tightly sleeving on the outer periphery of the columnar connection part is opened in the middle of the connection end cover, a front tapered hole for tightly sleeving on the outer periphery of the front tapered part is opened in the middle of the front fixing sleeve, and a rear tapered hole for tightly sleeving on the outer periphery of the rear tapered part is opened in the middle of the rear fixing sleeve; A dovetail groove is axially opened on the inner wall of the connection column hole, and a dovetail key for cooperating with the dovetail groove is axially opened on the outer wall of the columnar connection part; transmission keys are arranged on the outer walls of the front tapered part and the rear tapered part, and key grooves for cooperating with the transmission keys are opened on the inner walls of the front tapered hole and the rear tapered hole; Second threaded holes are opened on the outer periphery of the connection end cover, the magnetic sheet bracket, and the fixed pressing ring, and the connection end cover, the magnetic sheet bracket, and the fixed pressing ring are sequentially fixedly connected by second screws inserted into the second threaded holes in a matching manner, and a second nut is further sleeved on the rear end of the second screw; a fan-shaped heat dissipation opening is opened on the connection end cover; the base includes a bearing sleeve and a flange fixedly connected to the rear end of the bearing sleeve, the wire bracket is fixedly connected to the flange by a third screw, and two bearings are arranged between the rear end of the motor shaft and the bearing sleeve.

2. The brushless DC motor with smooth speed regulation according to claim 1, wherein The magnetic sheet bracket includes an annular body and a magnetic sheet groove opened on the inner wall of the annular body for cooperatively installing the magnetic steel sheets, the rear end of the magnetic sheet groove penetrates through to the rear end face of the annular body, and the front end of the magnetic sheet groove does not penetrate through the annular body; the fixed pressing ring is used to press against the rear end face of the magnetic steel sheet inserted into the magnetic sheet groove; A plurality of heat dissipation holes are opened at positions on the annular body between the magnetic sheet grooves.

3. The brushless DC motor with smooth speed regulation according to claim 2, wherein The magnetic disk groove is T-shaped in a cross-section parallel to the radial direction of the annular body. The magnetic disk groove includes a through groove with a width smaller than that of the magnetic steel sheet and a mounting groove with a width larger than that of the through groove, which are sequentially arranged from the inner wall of the annular body towards the inside. The magnetic steel sheet is fitted and inserted into the mounting groove.

4. The brushless DC motor with smooth speed regulation according to claim 3, wherein A plurality of clamping strips are fixedly connected to the back surface of the magnetic steel sheet that contacts the back inner wall of the mounting groove. The length direction of the clamping strip is parallel to the axial direction of the annular body; A clamping groove for the clamping strip to be fitted and inserted is formed on the back inner wall of the mounting groove; The cross-sections of the clamping strip and the clamping groove are both trapezoidal in an inverted shape.

5. The brushless DC motor with smooth speed regulation according to claim 4, characterized in that, An arc-shaped elastic sheet is also fixedly connected to the front inner wall of the mounting groove.

6. The brushless DC motor with smooth speed regulation according to claim 4 or 5, characterized in that, A glue injection hole is formed through the clamping strip along its length direction. Glue outlet holes communicating with the glue injection hole are formed on the side surfaces of the clamping strip that do not contact the magnetic steel sheet.

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