A micro high-power slotless brushless motor
By using a multi-pole rotor assembly and a rivetless, slotless iron core design, combined with a six-lobed rhomboid coil winding and a split end cover structure, the problems of jamming and overheating caused by the concentration of the motor's magnetic field are solved, thereby improving the stability of the motor's output torque and the control accuracy.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- DONGGUAN LANGYI ELECTRICAL TECH CO LTD
- Filing Date
- 2025-04-10
- Publication Date
- 2026-06-16
AI Technical Summary
Conventional servo motors on the market use a single-pole hollow cup motor, which leads to concentrated magnetic field strength. This causes problems such as magnetic field saturation inside the motor, jamming, jerking, large torque fluctuations, low starting torque, easy overheating, and low control accuracy.
The design employs a multi-pole rotor assembly and a rivetless, slotless iron core, combined with a six-lobed rhomboid coil winding and a split front and rear end cover structure, to achieve uniform magnetic field distribution, reduce eddy current losses and heat generation, and improve rotor balance and control accuracy.
It achieves uniform magnetic field distribution, reduces motor jamming and heat generation, improves output torque stability and control precision, and enhances the motor's application range and performance.
Smart Images
Figure CN224367608U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to motors, and more particularly to a miniature high-power slotless brushless motor. Background Technology
[0002] Commercially available servos use a single-pole hollow cup motor. Because the magnetic field strength of the magnets in a single-pole motor is too concentrated, it will have the following impact on the motor performance:
[0003] 1. If the magnetic field strength of a pair of pole magnets is too concentrated, it can easily cause the internal magnetic field of the motor to saturate, thus causing the motor to jam.
[0004] 2. The soft start and soft stop are not smooth and there will be a jerkiness.
[0005] 3. Large torque fluctuation.
[0006] 4. Low starting torque.
[0007] 5. The motor is prone to overheating and the temperature rises rapidly.
[0008] 6. Low control precision. Summary of the Invention
[0009] In order to overcome the shortcomings and deficiencies of the existing technology, the purpose of this utility model is to provide a miniature high-power slotless brushless motor.
[0010] The objective of this utility model is achieved through the following technical solution: a miniature high-power slotless brushless motor, comprising a housing, a stator assembly, a multi-pole rotor assembly, a PCB board, and a PCB support within the cavity of the housing. The multi-pole rotor assembly is disposed within the stator assembly and includes two magnetic yokes, a shaft, a bushing, multi-pole magnets, and a rotor outer sleeve. The surface of the bushing has four connecting planes. The multi-pole magnets are connected to the connecting planes of the bushing through an epoxy resin layer. The bushing and the two magnetic yokes are both sleeved on the shaft, with the bushing located between the two magnetic yokes. The two ends of the multi-pole magnets have insertion slots between them and the shaft. One end of each of the two magnetic yokes has an insertion protrusion that inserts into the insertion slot. The rotor outer sleeve is sleeved on the outer surface of the multi-pole magnets, and the PCB board is fixed on the PCB support. The bushing is quadrilateral in shape, which facilitates machining and ensures controllable precision. A rotor sleeve covers the multi-pole magnet to prevent it from detaching from the bushing. This structure ensures good fit between the multi-pole magnet and the shaft, guaranteeing rotor consistency and allowing for dynamic balancing, resulting in superior balancing and less overall motor vibration. An internal PCB wiring board facilitates the connection of the micro-motor windings. The magnetic yoke seals the magnetic field of the magnet, preventing magnetic attraction to the bearing and thus avoiding bearing damage.
[0011] As an improvement of this utility model's miniature high-power slotless brushless motor, the stator assembly includes a spool winding formed by six-lobed rhomboid coil winding laminations and an iron core. The spool winding is tightly attached to the inner wall of the iron core, and the leads of the spool winding are electrically connected to the PCB board. A bracket positioning groove is provided between one end of the spool winding and the inner wall of the housing, and the PCB bracket is embedded in the bracket positioning groove. A front cover positioning groove is provided between the other end of the spool winding and the inner wall of the housing. The stator structure adopts a rivet-free and slotless iron core. Compared with conventional slotless iron cores with rivets, some magnetic fields are not overly concentrated at the rivet positions, thus preventing motor jamming. The spool winding uses a unique six-lobed rhomboid coil winding. The spool is formed by six-lobed rhomboid laminations, which is more efficient, has lower current, and lower temperature rise compared to multi-layer winding structures, achieving small size and high torque.
[0012] As an improvement to this utility model of a miniature high-power slotless brushless motor, it also includes a front cover. The front cover has a mating step, and it covers the front end of the housing. The mating step is inserted into a positioning groove in the front cover. A front bearing mounting hole is provided in the middle of the front cover, and a front bearing is installed in the mounting hole. One end of the rotating shaft passes through the front bearing and extends out of the front cover. A front washer is provided between one of the magnetic yokes and the front bearing. The front cover, housing, and rear cover adopt a split design, which facilitates assembly and operation. After the motor assembly and testing are passed, laser spot welding is performed at the connection points of the front cover, housing, and rear cover to increase the detachment force at the connection points and make the structure more stable. The positioning steps on the front and rear covers ensure that the overall dimensions are met after assembly with the housing.
[0013] As an improvement of the present invention, a miniature high-power slotless brushless motor, it also includes a rear end cover. The rear end cover is provided with a positioning step. The rear end cover covers the rear end of the housing, and the positioning step is embedded in the housing. The middle part of the rear end cover is provided with a rear bearing mounting hole. A rear bearing is provided in the rear bearing mounting hole. The other end of the rotating shaft passes through the rear bearing and extends out of the rear end cover. The end of the rotating shaft extending out of the rear end cover is provided with a magnetic ring mounting seat. An induction magnetic ring is provided on the magnetic ring mounting seat. A first gasket is provided between the magnetic ring mounting seat and the rear bearing. A second gasket is provided between the rear bearing and the magnetic yoke.
[0014] As an improvement to the present invention's miniature high-power slotless brushless motor, it also includes an encoder rear cover, which covers the rear end cover. The encoder rear cover houses an FPC assembly and a silicone pad. An opening is provided on one side of the encoder rear cover, and a plastic terminal is located within the opening. The wires of the FPC assembly pass through the opening, and the FPC assembly corresponds to the induction magnetic ring. Internally, it contains a magnetic ring and a magnetic encoder. The encoder can output Hall signals and encoder signals, providing high control precision and allowing switching according to usage requirements, thus broadening its application range.
[0015] The beneficial effects of this invention are as follows: The multi-pole magnet of this invention uses two or more pairs of poles for magnetization, making the air gap magnetic field distribution of the motor more uniform. This is equivalent to uniformly distributing the magnetic field intensity concentrated in one pair of poles, preventing the magnetic field in the yoke (slotless iron core) from becoming too concentrated. This effectively reduces problems such as eddy current losses, heat generation, and motor jamming. Furthermore, the dispersed magnetic field distribution provides a more stable output torque for the motor. The magnet sleeve in this multi-pole rotor can be precision machined, ensuring good fit with the multi-pole magnet and shaft, resulting in more stable balance of the multi-pole rotor. A magnetic ring and magnetic encoder are provided at the tail of the motor. The encoder can output Hall signals and encoder signals, providing high control precision and allowing switching according to usage requirements, thus broadening its application range. Attached Figure Description
[0016] Figure 1 This is a cross-sectional view of the present invention;
[0017] Figure 2 This is a schematic diagram of the multi-stage rotor assembly structure of this utility model;
[0018] The attached figures are labeled as follows: 1. Housing; 2. Stator assembly; 3. Multi-pole rotor assembly; 4. PCB board; 5. PCB bracket; 6. Front cover; 7. Front gasket; 8. Rear cover; 9. Magnetic ring mounting base; 10. Induction magnetic ring; 11. First gasket; 12. Second gasket; 13. Encoder rear cover; 14. FPC assembly; 15. Silicone pad; 16. Opening; 17. Plastic terminal; 21. Coil winding; 22. Iron core; 23. Bracket positioning slot; 24. Front cover positioning slot; 31. Magnetic yoke; 32. Shaft; 33. Bushing; 34. Multi-pole magnet; 35. Rotor outer sleeve; 36. Insertion protrusion; 61. Butt joint step; 62. Front bearing mounting hole; 63. Front bearing; 81. Positioning step; 82. Rear bearing mounting hole; 83. Rear bearing. Detailed Implementation
[0019] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.
[0020] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in this utility model embodiment are only used to explain the relative positional relationship and movement of each component in a specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.
[0021] Furthermore, the use of terms such as "first" and "second" in this utility model is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. If the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this utility model.
[0022] like Figure 1 and Figure 2As shown, a miniature high-power slotless brushless motor includes a housing 1. A stator assembly 2, a multi-pole rotor assembly 3, a PCB board 4, and a PCB support 5 are housed within the cavity of the housing 1. The multi-pole rotor assembly 3 is housed within the stator assembly 2 and includes two magnetic yokes 31, a shaft 32, a bushing 33, multi-pole magnets 34, and a rotor outer sleeve 35. The surface of the bushing 33 has four connecting planes. The multi-pole magnets 34 are connected to the connecting planes of the bushing 33 via epoxy resin layers. The bushing 33 and the two magnetic yokes 31 are both fitted onto the shaft 32, with the bushing 33 located between the two magnetic yokes 31. The two ends of the multi-pole magnets 34 have insertion slots 37 between them and the shaft 32. One end of each of the two magnetic yokes 31 has an insertion protrusion 36 that inserts into the insertion slot 37. The rotor outer sleeve 35 is fitted onto the outer surface of the multi-pole magnets 34. The PCB board 4 is fixed to the PCB support 5. The bushing 33 is quadrilateral in shape, which facilitates machining and allows for controllable precision. A rotor sleeve 36 encases the multi-pole magnet 34 to prevent it from detaching from the bushing 33. This structure ensures good fit between the multi-pole magnet 34 and the shaft 32, guaranteeing rotor consistency and allowing for dynamic balancing, resulting in superior balancing and reduced overall motor vibration. An internal PCB wiring board facilitates the connection of the micro-motor windings. The magnetic yoke 31 encloses the magnetic field of the magnet, preventing magnetic attraction to the bearings and thus avoiding bearing damage.
[0023] Preferably, the stator assembly 2 includes a spool winding 21 formed by six-lobed rhombic coil winding laminations and an iron core 22. The spool winding 21 is tightly attached to the inner wall of the iron core 22. The leads of the spool winding 21 are electrically connected to the PCB board 4. A bracket positioning groove 23 is provided between one end of the spool winding 21 and the inner wall of the housing 1, and the PCB bracket 5 is embedded in the bracket positioning groove 23. A front end cover positioning groove 24 is provided between the other end of the spool winding 21 and the inner wall of the housing 1. The stator structure adopts a rivet-free and slotless iron core. Compared with conventional rivet-free and slotless iron cores, some magnetic fields are not too concentrated at the rivet positions, thus avoiding the impact of motor jamming. The spool winding uses a unique six-lobed rhombic coil winding. The spool is formed by six-lobed rhombic laminations, which is more efficient, has lower current, and lower temperature rise compared to multi-layer winding structures, achieving small size and high torque.
[0024] Preferably, the assembly also includes a front cover 6, which has a mating step 61. The front cover 6 covers the front end of the housing 1, and the mating step 61 is inserted into the positioning groove 24 of the front cover. The middle of the front cover 6 has a front bearing mounting hole 62, and a front bearing 63 is installed in the front bearing mounting hole 62. One end of the rotating shaft 32 passes through the front bearing 63 and extends out of the front cover 6. A front gasket 7 is provided between one of the magnetic yokes 31 and the front bearing 63. The front cover 6, the housing 1, and the rear cover adopt a split design, which is convenient for assembly and operation. After the motor assembly test is qualified, the connection between the front cover 6, the housing 1, and the rear cover is laser spot welded, which can increase the detachment force at the connection and make the structure more stable. The positioning steps on the front cover and the rear cover can achieve the required overall dimensions after assembly with the housing.
[0025] Preferably, it also includes a rear end cover 8, which has a positioning step 81. The rear end cover 8 covers the rear end of the housing 1, and the positioning step 81 is embedded in the housing 1. The middle part of the rear end cover 8 has a rear bearing mounting hole 82, and a rear bearing 83 is provided in the rear bearing mounting hole 82. The other end of the rotating shaft 32 passes through the rear bearing 83 and extends out of the rear end cover 8. The end of the rotating shaft 32 extending out of the rear end cover 8 has a magnetic ring mounting seat 9, and an induction magnetic ring 10 is provided on the magnetic ring mounting seat 9. A first gasket 11 is provided between the magnetic ring mounting seat 9 and the rear bearing 83, and a second gasket 12 is provided between the rear bearing 83 and the magnetic yoke 31.
[0026] Preferably, it also includes an encoder rear cover 13, which covers the rear end cover 8. The encoder rear cover 13 houses an FPC assembly 14 and a silicone pad 15. An opening 16 is provided on one side of the encoder rear cover 13, and a plastic terminal 17 is located within the opening 16. The wires of the FPC assembly 14 pass through the opening 16, and the FPC assembly 14 corresponds to the induction magnetic ring 10. Internally, it contains a magnetic ring and a magnetic encoder. The encoder can output Hall signals and encoder signals, providing high control precision and allowing switching according to usage requirements, thus broadening its application range.
[0027] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and structure of the present invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A miniature high-power slotless brushless motor, comprising a housing, characterized in that, The cavity of the housing houses a stator assembly, a multi-pole rotor assembly, a PCB board, and a PCB support. The multi-pole rotor assembly is housed within the stator assembly and includes two magnetic yokes, a shaft, a bushing, multi-pole magnets, and a rotor outer sleeve. The bushing has four connecting planes on its surface. The multi-pole magnets are connected to the connecting planes of the bushing via an epoxy resin layer. The bushing and the two magnetic yokes are both fitted onto the shaft, with the bushing positioned between the two magnetic yokes. The two ends of the multi-pole magnets have insertion slots with the shaft, and one end of each of the two magnetic yokes has an insertion protrusion that inserts into the insertion slot. The rotor outer sleeve is fitted onto the outer surface of the multi-pole magnets, and the PCB board is fixed to the PCB support.
2. The miniature high-power slotless brushless motor according to claim 1, characterized in that, The stator assembly includes a spool winding formed by six-lobed rhomboid coil winding laminations and an iron core. The spool winding is tightly attached to the inner wall of the iron core. The leads of the spool winding are electrically connected to the PCB board. A bracket positioning groove is provided between one end of the spool winding and the inner wall of the housing. The PCB bracket is embedded in the bracket positioning groove. A front cover positioning groove is provided between the other end of the spool winding and the inner wall of the housing.
3. The miniature high-power slotless brushless motor according to claim 1, characterized in that, It also includes a front cover, which has a mating step. The front cover covers the front end of the housing, and the mating step is inserted into the positioning groove of the front cover. The front cover has a front bearing mounting hole in the middle, and a front bearing is installed in the front bearing mounting hole. One end of the rotating shaft passes through the front bearing and extends out of the front cover. A front gasket is provided between one of the magnetic yokes and the front bearing.
4. The miniature high-power slotless brushless motor according to claim 1, characterized in that, It also includes a rear end cover, which has a positioning step. The rear end cover covers the rear end of the housing, and the positioning step is embedded in the housing. The middle part of the rear end cover has a rear bearing mounting hole, and a rear bearing is installed in the rear bearing mounting hole. The other end of the rotating shaft passes through the rear bearing and extends out of the rear end cover. The end of the rotating shaft extending out of the rear end cover has a magnetic ring mounting seat, and an induction magnetic ring is installed on the magnetic ring mounting seat. A first gasket is provided between the magnetic ring mounting seat and the rear bearing, and a second gasket is provided between the rear bearing and the magnetic yoke.
5. The miniature high-power slotless brushless motor according to claim 4, characterized in that, It also includes an encoder back cover, which covers the rear end cover. The encoder back cover contains an FPC assembly and a silicone pad. An opening is provided on one side of the encoder back cover, and a plastic terminal is provided in the opening. The wires of the FPC assembly pass through the opening, and the FPC assembly corresponds to the induction magnetic ring.