A brushless motor

Abstract

This invention discloses a brushless motor, relating to the field of motor technology. It includes a main motor housing and a motor cover, with a stator assembly, a rotor assembly, and a control board disposed between the main housing and the cover. The rotor assembly includes a shaft, on which a permanent magnet and a sleeve are fitted. The permanent magnet has a through hole, the inner diameter of which is larger than the outer diameter of the shaft. The sleeve is made of plastic and is interference-fitted with the shaft. Two sleeves are respectively disposed at the axial ends of the permanent magnet. Each sleeve includes a insertion part that extends axially into the through hole. The insertion part is interference-fitted with the inner wall of the through hole, allowing the radial support force of the permanent magnet to be transmitted from the inside to the outside. This creates a direct contact support structure between the insertion part and the inner wall of the through hole in the radial direction of the permanent magnet, achieving fixation without external radial clamping force. This invention solves the problems of difficult assembly and fixing of permanent magnets and the easy loss of magnetic properties in existing brushless motors.

Description

Technical Field

[0001] This invention relates to the field of motor technology, and more particularly to a brushless motor. Background Technology

[0002] Brushless motors, especially brushless DC motors and permanent magnet synchronous motors, are widely used in power tools, industrial automation equipment, home appliances, and new energy vehicles due to their advantages such as simple structure, high operating efficiency, low noise, long lifespan, and low maintenance costs. Brushless motors typically employ a structure where stator windings and a rotor assembly with permanent magnets work together, and normal operation is achieved through an electronic commutation device.

[0003] In existing technologies, permanent magnets in traditional brushless motors are typically mounted on the outer surface of the rotor core, with a sleeve fitted over them. Through interference fit pressing or heat fitting, the sleeve creates a radial constraint force on the permanent magnet, preventing it from detaching due to centrifugal force during high-speed rotation. However, on the one hand, sleeve pressing can easily cause uneven stress or damage to the permanent magnet during assembly; on the other hand, the sleeves are mostly made of brass, increasing the overall weight of the rotor and further increasing the rotor's moment of inertia at high speeds, which is detrimental to improving the motor's dynamic performance.

[0004] Therefore, existing brushless motors suffer from difficulties in fixing and assembling permanent magnets and are prone to magnetic performance loss. Summary of the Invention

[0005] The purpose of this invention is to provide a brushless motor that solves the problems of difficulty in fixing and assembling permanent magnets and easy loss of magnetic properties of permanent magnets in existing brushless motors.

[0006] To achieve this objective, the present invention adopts the following technical solution: This invention provides a brushless motor, including a motor main housing and a motor cover. A stator assembly, a rotor assembly and a control board are provided between the motor main housing and the motor cover. The rotor assembly includes a rotating shaft rotatably connected to the motor main housing. A permanent magnet and a sleeve are sleeved on the rotating shaft. The permanent magnet has through holes extending through both ends of its axial direction, and the inner diameter of the through holes is larger than the outer diameter of the rotating shaft. The sleeves are made of plastic and are interference-fitted with the rotating shaft. Two sleeves are respectively disposed at both ends of the permanent magnet's axial direction. Each sleeve includes a plug-in portion that extends into the through hole along the axial direction of the rotating shaft. The plug-in portion is interference-fitted with the inner wall of the through hole, so that the radial support force of the permanent magnet is transmitted from the inside to the outside, so that the plug-in portion and the inner wall of the through hole form a direct contact support structure in the radial direction of the permanent magnet, and achieve fixation without external radial clamping force.

[0007] Optionally, each of the plug-in portions is provided with a first groove and a first mating surface that are spaced apart from each other along its circumference. The first mating surface is arc-shaped and fits against the inner wall surface of the through hole. Each of the sleeves is provided with an abutment portion, and the abutment portion is provided with an abutment surface that fits against the end face of the permanent magnet.

[0008] Optionally, each sleeve is provided with alternating second grooves and second mating surfaces along its circumference, the second mating surfaces being arc-shaped and mating with the outer wall surface of the rotating shaft; Each of the sleeves is provided with a sleeve portion, and the sleeve portion, the abutment portion, and the insertion portion are connected sequentially along the axial direction of the rotating shaft. The sleeve portion is provided with an annular inner hole surface, and there is a gap between the inner hole surface and the outer wall surface of the rotating shaft.

[0009] Optionally, the outer diameters of the socket, the insertion, the abutment, and the permanent magnet increase in an increasing trend, and the socket, the insertion, and the abutment are integrally formed structures; One end of the first groove and one end of the second groove are respectively connected to the end of the insertion part away from the abutment part, and the other ends of the first groove and the second groove are closed.

[0010] Optionally, a first bearing is installed inside the main housing of the motor, and a second bearing coaxially arranged with the first bearing is installed inside the motor cover. The two ends of the rotating shaft are rotatably connected to the first bearing and the second bearing, respectively.

[0011] Optionally, the sleeve near the first bearing abuts against the first bearing, and the rotating shaft is fitted with a pad and a spring; The pad abuts against the second bearing, the spring is in a compressed state, one end of the spring abuts against the pad, and the other end of the spring abuts against the sleeve.

[0012] Optionally, the stator assembly includes a stator core sleeved on the outer wall of the permanent magnet, and stator supports are installed at both ends of the stator core along its axial direction. A stator coil electrically connected to the control board is wound on the stator support. One of the stator brackets abuts against the inner wall of the motor housing, and the other stator bracket is inserted into the control board. The motor cover is press-fitted with the control board.

[0013] Optionally, the stator core has a plurality of first connecting portions spaced apart along its axial direction, and each stator bracket has a second connecting portion that overlaps with the first connecting portion, and the stator coil is wound around the second connecting portion.

[0014] Optionally, the control board has a first positioning hole and a second positioning hole, and each stator bracket is provided with a positioning post and a positioning block; The positioning pins near the control board are inserted into the first positioning hole, and the positioning pins away from the control board abut against the inner wall of the motor housing; the positioning blocks near the control board are inserted into the second positioning hole, and the positioning blocks away from the control board abut against the inner wall of the motor housing.

[0015] Optionally, the control board has a clearance hole in the middle, and the stator bracket has a boss that abuts against the control board. The stator bracket, the positioning column, the positioning block and the boss are integrally formed.

[0016] Optionally, the number of positioning pins is set to four, the number of positioning blocks is set to four, and the number of bosses is set to two; Each of the positioning posts is located between the positioning block and the boss, and every two positioning blocks are located between the two positioning posts.

[0017] Optionally, the motor cover is provided with a wire hole, and the motor cover has multiple notches distributed along its circumference. The main housing of the motor is provided with a folding plate corresponding to the notch, and the folding plate is flipped and pressed against the notch.

[0018] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a brushless motor. By changing the fixing method of the permanent magnet, the traditional external pressure fixing structure is optimized into an internal support fixing structure, achieving a synergistic improvement in force path reconstruction and stress distribution optimization. Specifically, by setting sleeves that are interference-fitted with the shaft at both ends of the permanent magnet along the axial direction, and setting insertion parts on the sleeves to insert into the through holes of the permanent magnet, the permanent magnet is changed from being externally pressed and constrained to being fixed by an internal support structure. This changes the force path of the permanent magnet, allowing it to obtain support force from the inside to the outside in the radial direction. This effectively avoids the concentrated extrusion force generated on the outer surface of the permanent magnet during the traditional press-fitting process, reducing local stress concentration.

[0019] Furthermore, by ensuring the fit between the insertion part and the inner wall of the permanent magnet through-hole, the supporting force is distributed circumferentially, thereby dispersing the contact stress. This effectively reduces problems such as cracking, chipping, or magnetic degradation of the permanent magnet caused by stress concentration, improving the structural integrity and reliability of the permanent magnet. Simultaneously, this invention uses a plastic sleeve instead of a traditional metal sleeve, significantly reducing the overall mass of the rotor assembly while meeting structural strength requirements. This reduces the rotor's moment of inertia, improving the motor's dynamic response and start-stop performance, reducing energy loss, and increasing motor operating efficiency.

[0020] Furthermore, the radial support of the insertion part and the axial limiting of the sleeve ensure stable and reliable support for the permanent magnet under high-speed rotation, preventing it from loosening or falling off under centrifugal force, thereby further improving the structural stability of the rotor assembly and the safety of motor operation. Therefore, this invention solves the problems of difficult permanent magnet fixing and assembly and easy magnetic performance loss in existing brushless motors. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] The structures, proportions, sizes, etc., shown in the accompanying drawings of this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0023] Figure 1 A three-dimensional structural diagram of a brushless motor provided in an embodiment of the present invention; Figure 2 A front view of a brushless motor provided in an embodiment of the present invention; Figure 3 for Figure 2 A schematic diagram of the AA cross-sectional structure; Figure 4 for Figure 3 A magnified structural diagram at point B; Figure 5 This is a three-dimensional structural diagram of a rotor assembly in a brushless motor provided in an embodiment of the present invention; Figure 6 This is a schematic diagram of a half-section structure of a sleeve in a brushless motor provided in an embodiment of the present invention; Figure 7 This is a schematic diagram of a partially exploded structure of a brushless motor provided in an embodiment of the present invention; Figure 8 This is a three-dimensional structural diagram of a stator support in a brushless motor provided by an embodiment of the present invention; Figure 9This is a three-dimensional structural diagram of the motor cover in a brushless motor according to an embodiment of the present invention.

[0024] Illustration: 10. Motor housing; 11. Folding plate; 20. Motor cover; 21. Wire hole; 22. Notch; 23. Crimp post; 30. Stator assembly; 31. Stator core; 311. First connecting part; 32. Stator bracket; 321. Second connecting part; 322. Positioning post; 323. Positioning block; 324. Boss; 33. Stator coil; 40. Rotor assembly; 41. Shaft; 42. Permanent magnet; 421. Through hole; 43. Sleeve; 431. Insertion part; 4311. First groove; 4312. First mating surface; 4313. Second groove; 4314. Second mating surface; 432. Abutment part; 4321. Abutment surface; 433. Sleeve part; 4331. Inner hole surface; 50. Control panel; 51. First positioning hole; 52. Second positioning hole; 53. Clearance hole; 61. First bearing; 62. Second bearing; 70. Pad; 80. Spring. Detailed Implementation

[0025] To make the objectives, features, and advantages of this invention more apparent and understandable, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0026] In the description of this invention, it should be understood that the terms "upper," "lower," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. It should be noted that when a component is considered to be "connected" to another component, it can be directly connected to the other component or there may be a component positioned centrally in the connection.

[0027] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0028] This invention provides a brushless motor, such as... Figures 1 to 9As shown, it includes a motor main housing 10 and a motor cover 20. A stator assembly 30, a rotor assembly 40 and a control board 50 are provided between the motor main housing 10 and the motor cover 20. The rotor assembly 40 includes a rotating shaft 41 that is rotatably connected to the motor main housing 10. A permanent magnet 42 and a sleeve 43 are sleeved on the rotating shaft 41. The permanent magnet 42 has a through hole 421 that passes through both ends of its axial direction. The inner diameter of the through hole 421 is larger than the outer diameter of the rotating shaft 41. The sleeve 43 is made of plastic and is interference-fitted with the rotating shaft 41. The two sleeves 43 are respectively set at both ends of the permanent magnet 42. Each sleeve 43 includes a plug portion 431, which extends into the through hole 421 along the axial direction of the rotating shaft 41. The plug portion 431 is interference-fitted with the inner wall of the through hole 421, so that the radial support force of the permanent magnet 42 is transmitted from the inside to the outside, so that the plug portion 431 and the inner wall of the through hole 421 form a direct contact support structure in the radial direction of the permanent magnet 42, and achieve fixation without external radial clamping force.

[0029] It should be noted that the brushless motor provided in this embodiment of the invention uses plastic sleeves 43, which are interference-fitted with the shaft 41, at both ends of the permanent magnet 42. The sleeves 43 have insertion portions 431 that insert into the through holes 421 of the permanent magnet 42, allowing the insertion portions 431 to extend into the through holes 421 of the permanent magnet 42. This provides radial support and positioning for the permanent magnet 42, thereby achieving stable fixation. This structure eliminates the need for an integral metal sleeve 43 on the outside of the permanent magnet 42 for press-fitting, effectively avoiding uneven stress or damage to the permanent magnet 42 caused by traditional press-fitting processes, reducing assembly difficulty and improving assembly reliability. Furthermore, the sleeves 43 are made of plastic, which significantly reduces the overall weight of the rotor assembly 40 compared to traditional brass sleeves 43, lowering the rotor's moment of inertia and improving the motor's dynamic response performance and operating efficiency. Furthermore, the permanent magnet 42 is radially supported by the sleeve 43 insertion part 431, ensuring reliable structural support and positioning of the permanent magnet 42 even during high-speed motor rotation. This effectively prevents the permanent magnet 42 from loosening or falling off due to centrifugal force, improving the stability of the rotor structure and the safety of motor operation, thereby reducing magnet damage and extending the motor's service life. Therefore, this invention solves the problems of difficult assembly and fixing of the permanent magnet 42 in existing brushless motors, as well as the easy loss of magnetic properties in the permanent magnet 42.

[0030] It should also be noted that the fixing method of the permanent magnet 42 has been changed from the traditional radial compression constraint of the external sleeve 43 to an internal support structure achieved through the insertion part 431. This changes the force path of the permanent magnet 42, allowing it to receive support force radially from the inside out. This structure avoids the concentrated extrusion force generated on the outer surface of the permanent magnet 42 during the traditional external pressing process, reducing local stress concentration. Furthermore, the fit between the insertion part 431 and the inner wall of the through hole 421 of the permanent magnet 42 allows the support force to be distributed circumferentially along the inner wall of the permanent magnet 42, thereby dispersing the contact stress. This effectively reduces damage problems such as cracking, chipping, or magnetic degradation of the permanent magnet 42 caused by stress concentration, improving the structural integrity and reliability of the permanent magnet 42. Meanwhile, the present invention uses a plastic sleeve 43 instead of a traditional metal sleeve 43, which significantly reduces the overall mass of the rotor assembly 40 while meeting the requirements of structural strength and assembly, thereby reducing the moment of inertia of the rotor, which is beneficial to improving the dynamic response performance and start-stop performance of the motor, reducing energy loss, and improving the operating efficiency of the motor.

[0031] like Figures 3 to 6 As shown, each plug-in portion 431 is provided with alternating first grooves 4311 and first mating surfaces 4312 along its circumference. The first mating surfaces 4312 are arc-shaped and fit against the inner wall surface of the through hole 421. Each sleeve 43 is provided with an abutment portion 432, and the abutment portion 432 is provided with an abutment surface 4321 that fits against the end face of the permanent magnet 42. The abutment surface 4321 is planar. For example, the number of first grooves 4311 and first contact surfaces 4312 is eight; the specific number of first grooves 4311 and first contact surfaces 4312 can be adjusted according to the actual size of the sleeve 43.

[0032] In specific implementation, the first contact surface 4312 can form an arc-shaped contact with the inner wall of the through hole 421 of the permanent magnet 42. While ensuring that the insertion part 431 provides reliable radial support for the permanent magnet 42, it increases the contact area between the insertion part 431 and the inner wall of the through hole 421, improving support stability and positioning accuracy. At the same time, the first groove 4311 can provide appropriate elastic deformation space for the insertion part 431 during assembly, reducing the assembly resistance when the insertion part 431 is inserted into the through hole 421, reducing the local stress generated on the inner wall of the permanent magnet 42, and preventing the permanent magnet 42 from being squeezed and damaged during assembly, thereby improving the reliability of assembly. By forming an abutment surface 4321 on the abutment part 432 that fits with the end face of the permanent magnet 42, the sleeve 43 can effectively limit and support the permanent magnet 42 in the axial direction, thereby preventing the permanent magnet 42 from axially moving during motor operation and improving the installation stability of the permanent magnet 42.

[0033] Furthermore, by having multiple first grooves 4311 and multiple first contact surfaces 4312 evenly and alternately distributed along the circumference of the sleeve 43, the insertion part 431 forms multiple points of uniform support for the inner wall of the permanent magnet 42, which is conducive to evenly distributing the force and improving the overall stability of the permanent magnet 42 fixation, thereby further improving the structural reliability of the rotor assembly 40 under high-speed rotation and the stability of motor operation.

[0034] like Figure 3 and Figure 6 As shown, each sleeve 43 has a second groove 4313 and a second contact surface 4314 that are alternately distributed along its circumference. The second contact surface 4314 is arc-shaped and is in contact with the outer wall surface of the rotating shaft 41. Each sleeve 43 is provided with a sleeve portion 433, and the sleeve portion 433, the abutment portion 432, and the insertion portion 431 are connected sequentially along the axial direction of the rotating shaft 41. The sleeve portion 433 has an annular inner hole surface 4331, and there is a gap between the inner hole surface 4331 and the outer wall surface of the rotating shaft 41. For example, there are four second grooves 4313 and four second mating surfaces 4314; the specific number of second grooves 4313 and second mating surfaces 4314 can be adjusted according to the actual size of the sleeve 43.

[0035] In specific implementation, by alternately arranging second grooves 4313 and second mating surfaces 4314 along the circumference of the sleeve 43, the second mating surface 4314 is arc-shaped and fits against the outer wall of the rotating shaft 41, thereby forming a multi-point contact structure between the sleeve 43 and the rotating shaft 41. This is beneficial to improving the fit stability and positioning accuracy between the sleeve 43 and the rotating shaft 41. At the same time, the setting of the second grooves 4313 can provide a certain elastic buffer space when the sleeve 43 and the rotating shaft 41 are in an interference fit, allowing the sleeve 43 to undergo moderate deformation during assembly, thereby reducing assembly resistance and dispersing local stress, avoiding damage to the sleeve 43 structure or assembly difficulties caused by interference fit, and improving the reliability of assembly. Furthermore, by providing a sleeve portion 433 on the sleeve 43 and connecting the sleeve portion 433, the abutment portion 432, and the insertion portion 431 sequentially along the axial direction of the rotating shaft 41, the sleeve 43 can simultaneously perform multiple functions such as cooperating and fixing with the rotating shaft 41, axially limiting the permanent magnet 42, and radially supporting the through hole 421 of the permanent magnet 42, thereby further improving the overall structural stability of the rotor assembly 40.

[0036] Furthermore, the sleeve portion 433 is provided with an annular inner bore surface 4331, and a certain gap is formed between the inner bore surface 4331 and the outer wall surface of the rotating shaft 41. This allows the sleeve 43 to achieve stable contact through the second contact surface 4314 during assembly, while providing necessary deformation space for the sleeve 43 under stress. This helps to alleviate assembly stress and improve the stability of the fit, thereby further improving the structural reliability of the motor under high-speed operation. Because there is a gap between the inner bore surface 4331 and the outer wall surface of the rotating shaft 41, a connected air passage is formed between the through hole 421, the second groove 4313, and the inner bore surface 4331, which can dissipate heat from the high-speed rotating shaft 41.

[0037] like Figures 3 to 6 As shown, the outer diameters of the socket 433, insertion part 431, abutment part 432 and permanent magnet 42 increase in an increasing trend, and the socket 433, insertion part 431 and abutment part 432 are integrally formed structures. One end of the first groove 4311 and one end of the second groove 4313 are respectively connected to the end of the insertion part 431 away from the abutment part 432, and the other ends of the first groove 4311 and the second groove 4313 are both closed.

[0038] In practical implementation, the outer diameters of the sleeve 433, insertion part 431, abutment part 432, and permanent magnet 42 increase progressively, creating a step-by-step transitional structural relationship between the various structures. This improves the compactness and stability of the overall rotor assembly 40 structure and reduces assembly interference while ensuring structural strength. It also makes the fit between the sleeve 43 and the permanent magnet 42 more rational, improving assembly efficiency. Furthermore, the integrated molding structure of the sleeve 433, insertion part 431, and abutment part 432 makes the overall structure of the sleeve 43 more complete, avoiding the loosening or misalignment problems that may occur with traditional split structures. This improves the structural strength and reliability of the sleeve 43 and further enhances its support and limiting effect on the permanent magnet 42.

[0039] Furthermore, by having one end of the first groove 4311 and the second groove 4313 communicate with the end of the insertion part 431 away from the abutment part 432, while the other ends are both closed structures, the first groove 4311 and the second groove 4313 ensure that the sleeve 43 has a certain elastic deformation capability, while preventing the first groove 4311 and the second groove 4313 from penetrating the entire structure and weakening the overall strength of the sleeve 43. This structure not only helps to release stress and reduce assembly resistance during assembly, but also maintains the stability of the sleeve 43 structure during motor operation, thereby further improving the fixing reliability of the permanent magnet 42 and the safety and stability of the rotor assembly 40 under high-speed rotation.

[0040] like Figure 3As shown, a first bearing 61 is installed inside the motor housing 10, and a second bearing 62, coaxially arranged with the first bearing 61, is installed inside the motor cover 20. The two ends of the rotating shaft 41 are rotatably connected to the first bearing 61 and the second bearing 62. For example, both the first bearing 61 and the second bearing 62 can be ball bearings.

[0041] In practical implementation, the rotating shaft 41 can be rotatably connected to both the first bearing 61 and the second bearing 62, forming a support structure for both ends of the rotating shaft 41. This structure can effectively improve the support stability of the rotating shaft 41, reduce the radial sway and vibration of the rotating shaft 41 during motor operation, and improve the smoothness of the rotation of the rotating shaft 41. At the same time, the first bearing 61 and the second bearing 62 are coaxially arranged, which allows the rotating shaft 41 to maintain good coaxiality during rotation, which helps to reduce the frictional resistance and energy loss during the operation of the rotor assembly 40, thereby improving the operating efficiency of the motor.

[0042] like Figure 3 and Figure 5 As shown, the sleeve 43 near the first bearing 61 abuts against the first bearing 61, and the rotating shaft 41 is fitted with a pad 70 and a spring 80; The pad 70 abuts against the second bearing 62, the spring 80 is in a compressed state, one end of the spring 80 abuts against the pad 70, and the other end of the spring 80 abuts against the sleeve 43.

[0043] In specific implementation, by having the sleeve 43 near the first bearing 61 abut against the first bearing 61, the permanent magnet 42 can form a stable support and positioning in the axial direction, thereby improving the installation stability of the permanent magnet 42 and helping to reduce axial movement of the permanent magnet 42 during operation. Simultaneously, by setting a pad 70 and a spring 80 on the rotating shaft 41, and having the pad 70 abut against the second bearing 62, the spring 80 is in a compressed state and abuts against both the pad 70 and the sleeve 43, thus forming an elastic preload structure in the axial direction of the rotating shaft 41. This structure can provide a continuous axial preload force to the permanent magnet 42, preventing gaps or loosening of the permanent magnet 42 during operation. Furthermore, the elasticity of the spring 80 can buffer and absorb the axial vibration generated by the rotating shaft 41 to a certain extent during motor operation, thereby further improving the smoothness of motor operation, reducing operating noise, and improving the overall reliability and service life of the motor.

[0044] like Figure 3 , Figure 7 and Figure 8 As shown, the stator assembly 30 includes a stator core 31 sleeved on the outer wall of the permanent magnet 42. Stator supports 32 are installed at both ends of the stator core 31 along its axial direction. Stator coils 33 that are electrically connected to the control board 50 are wound on the stator supports 32. One stator bracket 32 ​​abuts against the inner wall of the motor housing 10, and the other stator bracket 32 ​​is inserted into the control board 50. The motor cover 20 is press-fitted to the control board 50. In this embodiment, the inner side of the motor cover 20 is provided with four press-fitting posts 23 that press-fit with the control board 50. Through the press-fitting of the four press-fitting posts 23, the control board 50 and the stator assembly 30 are press-fitted and fixed inside the motor housing 10.

[0045] In specific implementation, stator supports 32 are installed at both ends of the stator core 31 along its axial direction, enabling the stator core 31 to be stably installed through the stator supports 32, thereby improving the overall structural stability of the stator assembly 30. Simultaneously, by winding stator coils 33, which are electrically connected to the control board 50, on the stator supports 32, a reliable electrical connection between the stator coils 33 and the control board 50 is achieved, facilitating electronic commutation control of the motor and improving the control accuracy and working efficiency of the motor operation.

[0046] Furthermore, by having one stator bracket 32 ​​abut against the inner wall of the motor main housing 10, the stator assembly 30 can be stably positioned within the motor main housing 10. The other stator bracket 32 ​​is inserted into the control board 50, and the control board 50 can be reliably fixed inside the motor through the press fit between the motor cover 20 and the control board 50. This results in a compact and stable internal structure layout for the motor, which simplifies the assembly process and improves the overall stability and reliability of the motor structure.

[0047] like Figure 7 and Figure 8 As shown, a plurality of first connecting portions 311 are distributed at intervals along the axial direction inside the stator core 31, and each stator support 32 is provided with a second connecting portion 321 that overlaps with the first connecting portions 311. The stator coil 33 is wound around the second connecting portion 321. In this embodiment, there are six first connecting portions 311 and six second connecting portions 321.

[0048] In specific implementation, by arranging multiple first connecting portions 311 axially spaced within the stator core 31 and providing second connecting portions 321 on the stator support 32 that overlap with the first connecting portions 311, a stable connection between the stator support 32 and the stator core 31 is achieved. This improves the overall installation stability of the stator assembly 30 and prevents loosening or displacement during motor operation. Simultaneously, by winding the stator coil 33 around the second connecting portion 321, the stator coil 33 can be stably wound on the stator support 32. The cooperation between the second connecting portion 321 and the first connecting portion 311 provides reliable support for the coil structure, thereby improving the firmness and neatness of the stator coil 33 installation.

[0049] Furthermore, by having multiple first connecting parts 311 corresponding to multiple second connecting parts 321, a multi-point connection structure is formed between the stator support 32 and the stator core 31, which can effectively distribute the force, improve the overall connection strength, and further enhance the structural stability and reliability of the stator assembly 30 during motor operation, thereby helping to improve the motor's operating stability and service life.

[0050] like Figure 3 , Figure 7 and Figure 8 As shown, the control board 50 has a first positioning hole 51 and a second positioning hole 52, and each stator bracket 32 ​​is provided with a positioning post 322 and a positioning block 323; The positioning post 322 near the control board 50 is inserted into the first positioning hole 51, and the positioning post 322 away from the control board 50 abuts against the inner wall of the motor main housing 10; the positioning block 323 near the control board 50 is inserted into the second positioning hole 52, and the positioning block 323 away from the control board 50 abuts against the inner wall of the motor main housing 10. In this embodiment, since both ends of the stator core 31 are stator brackets 32 with the same structure, there is no need to consider the assembly direction, and the stator assembly 30 can be quickly assembled into the motor main housing 10, improving the assembly efficiency of the motor.

[0051] In practice, the positioning post 322 engages with the first positioning hole 51, and the positioning block 323 engages with the second positioning hole 52, achieving precise positioning and reliable connection between the stator bracket 32 ​​and the control board 50. This improves assembly accuracy and prevents positional deviations during assembly. Simultaneously, by having the positioning post 322 and positioning block 323, located away from the control board 50, abut against the inner wall of the motor housing 10, the stator bracket 32 ​​forms a bidirectional limiting structure between the motor housing 10 and the control board 50. This effectively constrains the stator bracket 32 ​​in both the axial and radial directions, further enhancing the stability of the stator assembly 30 installation.

[0052] In addition, the positioning column 322 and the positioning block 323 are designed to cooperate to provide guidance for the stator bracket 32 ​​during assembly, which helps to simplify the assembly steps, improve assembly efficiency, and effectively prevent the stator assembly 30 from loosening or shifting during motor operation, thereby improving the reliability and operational stability of the overall motor structure.

[0053] like Figure 3 and Figure 7As shown, the control plate 50 has a clearance hole 53 in the middle, and the stator bracket 32 ​​has a boss 324 that abuts against the control plate 50. The stator bracket 32, positioning posts 322, positioning blocks 323, and bosses 324 are integrally formed. There are four positioning posts 322, four positioning blocks 323, and two bosses 324. There are four first positioning holes 51 and four second positioning holes 52. Each positioning post 322 is located between a positioning block 323 and a boss 324, and every two positioning blocks 323 are located between two positioning posts 322.

[0054] In specific implementation, by setting a clearance hole 53 in the middle of the control plate 50, the boss 324 on the stator bracket 32 ​​can reasonably avoid interference with the control plate 50, thus ensuring smooth assembly between components and improving the overall structural compatibility. Simultaneously, by setting a boss 324 on the stator bracket 32 ​​that abuts against the control plate 50, a stable supporting contact relationship is formed between the stator bracket 32 ​​and the control plate 50, providing effective support for the control plate 50 and preventing deformation or vibration during motor operation, thereby improving the stability and reliability of the control plate 50 installation. Furthermore, by rationally setting the number and relative positions of the positioning posts 322, positioning blocks 323, and bosses 324, the structures are evenly distributed circumferentially. This not only improves the positioning accuracy and stress uniformity between the stator bracket 32 ​​and the control plate 50 but also enhances the overall structural stability, thereby further improving the reliability and stability of the motor during operation.

[0055] like Figures 1 to 9 As shown, the motor cover 20 has a wire hole 21, and the motor cover 20 has multiple notches 22 distributed around its circumference. The motor main housing 10 has a folding plate 11 corresponding to the notches 22, and the folding plate 11 is flipped and pressed against the notches 22. In this embodiment, there are four notches 22 and four folding plates 11.

[0056] In practical implementation, elongated wire-passing holes 21 are provided on the motor cover 20, allowing the wires of the control board 50 to be led out through the holes 21. This facilitates electrical connection between the motor and an external power supply or control system, improving the practicality of the overall motor structure and the convenience of wiring. Simultaneously, multiple notches 22 are provided circumferentially on the motor cover 20, and corresponding folding plates 11 are provided on the motor main housing 10. These folding plates 11 can be flipped and pressed against the notches 22, thus achieving reliable fixation between the motor main housing 10 and the motor cover 20. This structure eliminates the need for additional screws or other fasteners, simplifying the assembly process and improving assembly efficiency.

[0057] Working Principle: The brushless motor provided by this invention uses plastic sleeves 43, which are interference-fitted with the shaft 41, at both ends of the permanent magnet 42. Each sleeve 43 has an insertion part 431 that inserts into the through hole 421 of the permanent magnet 42, allowing the insertion part 431 to extend into the through hole 421 of the permanent magnet 42. This provides radial support and positioning for the permanent magnet 42, thus achieving stable fixation. This structure eliminates the need for an integral metal sleeve 43 on the outside of the permanent magnet 42 for press-fitting, effectively avoiding uneven stress or damage to the permanent magnet 42 caused by traditional press-fitting processes, reducing assembly difficulty and improving assembly reliability. Furthermore, the plastic material used for the sleeves 43 significantly reduces the overall weight of the rotor assembly 40 compared to traditional brass sleeves 43, lowering the rotor's moment of inertia and improving the motor's dynamic response performance and operating efficiency. Furthermore, the permanent magnet 42 is radially supported by the sleeve 43 insertion part 431, ensuring reliable structural support and positioning of the permanent magnet 42 even during high-speed motor rotation. This effectively prevents the permanent magnet 42 from loosening or falling off due to centrifugal force, improving the stability of the rotor structure and the safety of motor operation, thereby reducing magnet damage and extending the motor's service life. Therefore, this invention solves the problems of difficult assembly and fixing of the permanent magnet 42 in existing brushless motors, as well as the easy loss of magnetic properties in the permanent magnet 42.

[0058] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A brushless electric motor characterized by, The device includes a motor housing and a motor cover. A stator assembly, a rotor assembly, and a control board are provided between the motor housing and the motor cover. The rotor assembly includes a rotating shaft that is rotatably connected to the motor housing. A permanent magnet and a sleeve are fitted onto the rotating shaft. The permanent magnet has through holes extending through both ends of its axial direction, and the inner diameter of the through holes is larger than the outer diameter of the rotating shaft; the sleeve is made of plastic material and is interference-fitted with the rotating shaft, and the two sleeves are respectively disposed at both ends of the permanent magnet's axial direction. Each of the sleeves includes a plug portion that extends into the through hole along the axial direction of the rotating shaft; the plug portion is interference-fitted with the inner wall of the through hole, so that the radial support force of the permanent magnet is transmitted from the inside to the outside, so that the plug portion and the inner wall of the through hole form a direct contact support structure in the radial direction of the permanent magnet, and achieve fixation without external radial clamping force.

2. The brushless motor according to claim 1, characterized in that, Each of the plug-in portions is provided with alternating first grooves and first mating surfaces distributed at intervals along its circumference. The first mating surfaces are arc-shaped and fit against the inner wall surface of the through hole. Each of the sleeves is provided with an abutment portion, and the abutment portion is provided with an abutment surface that fits against the end face of the permanent magnet.

3. The brushless motor according to claim 2, characterized in that, Each of the sleeves has a second groove and a second contact surface that are alternately distributed along its circumference. The second contact surface is arc-shaped and is in contact with the outer wall surface of the rotating shaft. Each of the sleeves is provided with a sleeve portion, and the sleeve portion, the abutment portion, and the insertion portion are connected sequentially along the axial direction of the rotating shaft. The sleeve portion is provided with an annular inner hole surface, and there is a gap between the inner hole surface and the outer wall surface of the rotating shaft.

4. The brushless motor according to claim 3, characterized in that, The outer diameters of the socket, the insertion part, the abutment part, and the permanent magnet increase in an increasing trend, and the socket, the insertion part, and the abutment part are integrally formed structures; One end of the first groove and one end of the second groove are respectively connected to the end of the insertion part away from the abutment part, and the other ends of the first groove and the second groove are closed.

5. The brushless motor according to any one of claims 1 to 4, characterized in that, A first bearing is installed inside the main housing of the motor, and a second bearing coaxially arranged with the first bearing is installed inside the motor cover. The two ends of the rotating shaft are rotatably connected to the first bearing and the second bearing respectively.

6. The brushless motor according to claim 5, characterized in that, The sleeve near the first bearing abuts against the first bearing, and the rotating shaft is fitted with a pad and a spring; The pad abuts against the second bearing, the spring is in a compressed state, one end of the spring abuts against the pad, and the other end of the spring abuts against the sleeve.

7. The brushless motor according to claim 1, characterized in that, The stator assembly includes a stator core sleeved on the outer wall of the permanent magnet body. Stator supports are installed at both ends of the stator core along its axial direction. Stator coils electrically connected to the control board are wound on the stator supports. One of the stator brackets abuts against the inner wall of the motor housing, and the other stator bracket is inserted into the control board. The motor cover is press-fitted with the control board.

8. The brushless motor according to claim 7, characterized in that, The stator core has a plurality of first connecting parts spaced apart along its axial direction. Each stator bracket has a second connecting part that overlaps with the first connecting parts. The stator coil is wound around the second connecting part.

9. The brushless motor according to claim 7, characterized in that, The control board is provided with a first positioning hole and a second positioning hole, and each stator bracket is provided with a positioning post and a positioning block; The positioning pins near the control board are inserted into the first positioning hole, and the positioning pins away from the control board abut against the inner wall of the motor housing; the positioning blocks near the control board are inserted into the second positioning hole, and the positioning blocks away from the control board abut against the inner wall of the motor housing.

10. The brushless motor according to claim 9, characterized in that, The control board has a clearance hole in the middle, and the stator support has a boss that abuts against the control board. The stator support, the positioning column, the positioning block and the boss are integrally formed.

11. The brushless motor according to claim 10, characterized in that, The number of positioning pins is set to four, the number of positioning blocks is set to four, and the number of bosses is set to two; Each of the positioning posts is located between the positioning block and the boss, and every two positioning blocks are located between the two positioning posts.

12. The brushless motor according to claim 1, characterized in that, The motor cover is provided with a wire hole, and the motor cover has multiple notches distributed along its circumference. The main housing of the motor is provided with a folding plate corresponding to the notch, and the folding plate is flipped and pressed against the notch.

Images