Hollow cup brushless servo motor

Abstract

The embodiment of the invention relates to the technical field of motors, in particular to a coreless brushless servo motor, solves the problems that a traditional brush servo motor is heavy in size, low in efficiency and short in service life, and improves the connection stability of an output end through the coaxial arrangement of a sleeve and a driving shaft. The application of the brushless motor eliminates the friction loss of the electric brush, the integrated structural design realizes the miniaturization of the equipment, and the closed mounting cavity effectively protects the internal components from being influenced by the external environment.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of motors, and more particularly to a coreless brushless servo motor. Background Art

[0002] Currently, servo motors generally use brushed DC motors as the driving core, combined with potentiometers or optical encoders for position feedback to form a closed-loop control system. Such designs are widely used in fields such as robotics, model aircraft, and industrial automation, but they have the following inherent defects: (1) Volume and weight issues: Brushed motors require the internal installation of brush and commutator structures, resulting in a large axial length and a bulky overall volume, making it difficult to meet the requirements of modern lightweight equipment.

[0003] (2) Efficiency and lifespan limitations: Mechanical friction of the brushes leads to high energy losses (efficiency is usually <70%), and it is also prone to generate sparks and electromagnetic interference. Brush wear limits the lifespan (typical lifespan is about 50,000 cycles), and frequent maintenance is required.

[0004] (3) Poor concentricity between the motor drive shaft and the casing sleeve: The auxiliary connection sleeves of existing servo motors are generally set on the casing, resulting in a deviation between the casing sleeve and the drive shaft, leading to low concentricity and affecting the connection stability between the motor and the drive equipment. Summary of the Invention

[0005] In view of the above problems, the embodiments of the present invention provide a coreless brushless servo motor, which solves the problems of large volume and weight, high energy loss and short lifespan of existing brushed motors, and poor concentricity between the motor drive shaft and the casing sleeve.

[0006] In a first aspect, the present invention provides a coreless brushless servo motor, comprising: A casing with an internal installation cavity, and a drive through-hole is provided on one end face of the casing, and the drive through-hole is communicated with the installation cavity; A motor assembly disposed in the installation cavity, the motor assembly includes a motor main body and a front cover disposed on the motor main body, the front cover is provided with a sleeve, and the sleeve is disposed around the drive shaft of the motor main body; and when the front cover is fixed in the installation cavity, the sleeve extends out along the drive through-hole; And a circuit board assembly disposed in the installation cavity and electrically connected to the motor assembly, and the circuit board assembly is used to drive the motor assembly to work.

[0007] In some alternative ways, the front cover is injection-molded by placing the driving end of the motor body in an injection mold, and after the front cover is injection-molded, the sleeve is coaxially arranged with the drive shaft.

[0008] In some alternative ways, the housing includes a main housing and a cover plate. The main housing has an installation opening and a clamping groove is provided on the side wall of the main housing. The cover plate is provided with a buckle; when the cover plate covers the installation opening, the buckle is clamped and fixed in the clamping groove.

[0009] In some alternative ways, at least one first installation hole is provided on the side surface of the front cover, and a second installation hole matching the first installation hole is provided on the main housing. The first installation hole and the second installation hole are positioned and fixed by a pin.

[0010] In some alternative ways, the circuit board assembly includes a first circuit board, a second circuit board and a connector. The first circuit board is electrically connected to the second circuit board. The second circuit board is electrically connected to the motor assembly. The connecting wire harness of the connector passes through the wire groove of the cover plate and is connected to the first circuit board; wherein, the first circuit board is arranged in the installation cavity along a first direction, and the second circuit board is arranged in the installation cavity along a second direction.

[0011] In some alternative ways, a receiving groove is dug at the upper end of the cover plate, at least one positioning pin is arranged in the receiving groove, and a positioning hole matching the positioning pin is provided on the first circuit board. The first circuit board is fixed on the cover plate along the positioning pin.

[0012] In some alternative ways, the first circuit board is further provided with a slot, and the first circuit board is provided with a first pad; one end of the second circuit board is provided with a plug block matching the slot, and the plug block is provided with a second pad; when the second circuit board is plugged on the first circuit board, the first pad and the second pad are connected by a welding strip; the second circuit board is further provided with a third pad connected to the motor assembly.

[0013] In some alternative ways, the motor assembly is further provided with an induction magnetic group. The induction magnetic group includes a fixed seat and a magnetic sheet. A connecting groove connected to the drive shaft is provided at the upper end of the fixed seat, and an installation groove for fixing the magnetic sheet is provided at the lower end of the fixed seat; a Hall sensor is provided on the first circuit board, and the Hall sensor is arranged axially below the induction magnetic group along the motor assembly; the second circuit board is integrally provided with an MCU module, a drive module and a power management module. The power management module is connected to the MCU module, the drive module and the Hall sensor. The MCU module is connected to the drive module and the Hall sensor to control the drive of the motor assembly.

[0014] In some alternative embodiments, the motor body includes a drive shaft, a magnetic ring, a coil, a housing, a rear cover, a third circuit board, a first bearing, and a second bearing; One end of the housing is connected to the front cover and the other end is connected to the rear cover. The coil is disposed on the inner wall of the housing. The first bearing is disposed in a first mounting groove in the middle of the front cover. The second bearing is disposed in a second mounting groove in the middle of the rear cover. Two ends of the drive shaft are respectively slidably connected to the first bearing and the second bearing. The magnetic ring is disposed on the drive shaft and is located inside the coil. The third circuit board is disposed on the rear cover and the third circuit board is electrically connected to the coil.

[0015] In some alternative embodiments, the main housing of the casing is made of an aluminum shell material, and the cover plate of the casing is a plastic part; the wire diameter of the winding of the coil is less than 0.1 mm, and the resistance value of the coil is 16.4 Ω ± 8%; wherein, the working parameters of the coreless brushless servo motor are set to any one or more of a positioning accuracy ≤ ±1°, a rotation angle of 360°, a working voltage of 4V to 9V, and a working current less than 650 mA, and the mass of the coreless brushless servo motor ≤ 7 g.

[0016] The embodiment of the present invention provides a coreless brushless servo motor, and its beneficial effects are as follows: 1. The coreless brushless servo motor of the present invention includes a casing, a motor assembly, and a circuit board assembly; the casing has an internal installation cavity, and a drive through hole is provided on one end face of the casing, and the drive through hole is communicated with the installation cavity; the motor assembly is disposed in the installation cavity, and the motor assembly includes a motor body and a front cover disposed on the motor body. The front cover is provided with a sleeve, and the sleeve is disposed on the periphery of the drive shaft of the motor body; and when the front cover is fixed in the installation cavity, the sleeve extends out along the drive through hole; the circuit board assembly is disposed in the installation cavity and is electrically connected to the motor assembly, and the circuit board assembly is used to drive the motor assembly to work. It solves the problems of the traditional brushed servo motor being bulky, having low efficiency, and short lifespan. At the same time, the coaxial setting of the sleeve and the drive shaft improves the stability of the output end connection. The application of the brushless motor eliminates the brush friction loss, and the integrated structure design realizes the miniaturization of the device. The enclosed installation cavity effectively protects the internal components from the external environment.

[0017] 2. For the coreless brushless servo motor of the present invention, the wire diameter of the coil winding is less than 0.1 mm, and the resistance value of the coil is 16.4 Ω ± 8%. It can achieve a static current of the motor < 40 mA, a working current < 500 mA at room temperature such as 25 °C, a working current < 650 mA at low temperature such as -45 °C, and a working current < 400 mA at high temperature such as 65 °C. This greatly reduces the energy consumption of the coreless brushless servo motor, saves energy, and reduces the output requirements of the energy supply equipment. At the same time, it can achieve an extremely long service life, enabling the coreless brushless servo motor to operate without failure for a time ≥ 20000H.

[0018] The above description is only an overview of the technical solutions of the embodiments of the present invention. In order to be able to understand the technical means of the embodiments of the present invention more clearly, it can be implemented in accordance with the content of the specification. And in order to make the above and other purposes, features, and advantages of the embodiments of the present invention more obvious and understandable, the following specifically gives the specific implementation manners of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings are only used to illustrate the embodiments and are not considered to be a limitation of the present invention. Moreover, throughout the drawings, the same reference numerals are used to represent the same components. In the drawings: Figure 1 shows a schematic structural diagram of the coreless brushless servo motor provided by the present invention; Figure 2 shows an exploded schematic diagram of the coreless brushless servo motor provided by the present invention; Figure 3 shows a schematic cross-sectional view of the coreless brushless servo motor provided by the present invention; Figure 4 shows a schematic cross-sectional view of the motor assembly provided by the present invention; Figure 5 shows an exploded schematic diagram of the circuit board assembly provided by the present invention; Figure 6 shows a schematic cross-sectional view of the circuit board assembly provided by the present invention.

[0020] Among them, 1. Housing; 11. Main housing; 111. Driving through hole; 112. Second mounting hole; 113. Card slot; 12. Cover plate; 121. Accommodating groove; 122. Positioning pin; 123. Snap; 2. Motor assembly; 21. Motor main body; 211. Driving shaft; 212. Outer shell; 213. Magnetic ring; 214. Rear cover; 215. Third circuit board; 216. First bearing; 217. Second bearing; 22. Front cover; 221. First mounting hole; 23. Sleeve; 24. Inductive magnetic group; 241. Fixed seat; 242. Magnetic sheet; 3. Circuit board assembly; 31. First circuit board; 311. Slot; 312. First pad; 313. Welding strip; 314. Positioning hole; 32. Second circuit board; 321. Insert block; 322. Second pad; 323. Third pad; 33. Connector; 34. Hall sensor; 4. Installation cavity. Detailed implementation mode

[0021] The exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein.

[0022] Embodiment 1: Figure 1-6 The first embodiment of the brushless servo motor with a hollow cup of the present invention is shown. The brushless servo motor with a hollow cup of the present invention includes a housing 1, a motor assembly 2, and a circuit board assembly 3. An installation cavity 4 is provided inside the housing 1, and a driving through hole 111 is provided on one end face of the housing 1, and the driving through hole 111 is communicated with the installation cavity 4; the motor assembly 2 is arranged in the installation cavity 4, and the motor assembly 2 includes a motor main body 21 and a front cover 22 arranged on the motor main body 21. The front cover 22 is provided with a sleeve 23, and the sleeve 23 is arranged on the periphery of the driving shaft 211 of the motor main body 21; when the front cover 22 is fixed in the installation cavity 4, the sleeve 23 extends out along the driving through hole 111; the circuit board assembly 3 is arranged in the installation cavity 4 and is electrically connected to the motor assembly 2.

[0023] Among them, the installation cavity 4 refers to the enclosed space inside the housing 1 for accommodating the motor assembly 2 and the circuit board assembly 3. Specifically, it can be realized by a stamping and stretching forming shell, which is used to realize the integrated layout of components. The driving through hole 111 refers to a circular through hole penetrating the end face of the housing 1, and the aperture is matched with the protruding part of the sleeve 23, which is used to ensure the docking accuracy between the output end of the driving shaft 211 and the external device. The front cover 22 refers to the bearing structure fixed at the end of the motor main body 21. Specifically, it can be combined with the motor main body 21 by an injection molding process, which is used to bear the sleeve 23 and realize the positioning connection with the housing 1. The sleeve 23 refers to a metal tubular structure sleeved on the outer periphery of the driving shaft 211, and there is a gap between the inner diameter and the driving shaft 211, which is used to protect the driving shaft 211 and improve the coaxiality of the output end connection.

[0024] Specifically, the motor assembly 2 is fixed in the installation cavity 4 of the housing 1 through the front cover 22. The sleeve 23 on the front cover 22 extends out of the housing 1 along the drive through-hole 111 during the installation process. The coaxiality between the sleeve 23 and the drive shaft 211 is ensured by the injection molding process, improving the connection stability between the output end of the drive shaft 211 and the external device. The circuit board assembly 3 is directly integrated in the installation cavity 4 and is electrically connected to the motor assembly 2 through internal wiring, eliminating the cable redundancy of the traditional external control module. The closed structure of the installation cavity 4 enables the motor assembly 2 and the circuit board assembly 3 to form a compact layout, effectively reducing the overall volume. In this embodiment, the coreless brushless servo motor can be a brushless servo actuator, which can be specifically used to drive the antenna to rotate to change the antenna angle.

[0025] Compared with the prior art, the traditional brushed motor needs to be provided with a brush and a commutator structure, resulting in an increase in the axial length. However, the brushless motor adopted in this solution eliminates the mechanical commutation structure through electronic commutation. The sleeve 23 of the traditional motor is arranged on the housing 1, and there is an assembly error with the motor drive shaft 211. In this solution, the sleeve 23 is integrated on the front cover 22 of the motor assembly 2, and the concentricity is ensured by synchronous molding. The traditional circuit board needs to be externally installed, while this solution realizes space optimization through internal integration.

[0026] Through the above technical solution, this application solves the problems of the traditional brushed servo motor being bulky, inefficient, and having a short lifespan. At the same time, the stability of the output end connection is improved by the coaxial setting of the sleeve 23 and the drive shaft 211. The application of the brushless motor eliminates the brush friction loss, and the integrated structure design realizes the miniaturization of the device. The closed installation cavity 4 effectively protects the internal components from the external environment.

[0027] Embodiment 2: This embodiment is based on Embodiment 1, and this embodiment specifically further describes the housing 1, the motor assembly 2, and the circuit board assembly 3.

[0028] In one implementation manner of this embodiment, the front cover 22 is injection-molded by placing the drive end of the motor body 21 in an injection mold. After the front cover 22 is injection-molded, the sleeve 23 and the drive shaft 211 are coaxially arranged.

[0029] In this embodiment, the injection molding process refers to using the drive end of the motor body 21 as the mold positioning reference, and forming the front cover 22 by injecting thermoplastic or thermosetting materials into the mold. Specifically, it can be achieved by using polyamide, polycarbonate or reinforced nylon materials. The geometric constraints of the mold are utilized to ensure a fixed spatial relationship between the sleeve 23 and the drive shaft 211. Among them, the coaxial setting of the sleeve 23 and the drive shaft 211 means that during the injection molding process, the mold cavity is positioned with the axis of the drive shaft 211 as the axis reference, so that the axis of the cured sleeve 23 coincides with the axis of the drive shaft 211, eliminating the axis offset caused by the reference switching during the assembly process.

[0030] Specifically, during the injection molding process, the drive shaft 211 of the motor body 21 is fixed in the positioning structure of the mold cavity, and the liquid injection molding material is evenly filled circumferentially around the drive shaft 211 to form the front cover 22 and the sleeve 23. When the mold is closed, the drive shaft 211 serves as a rigid positioning reference, and its axis direction is orthogonal to the mold parting surface. The injection molding material maintains the coaxial relationship between the sleeve 23 and the drive shaft 211 through the shrinkage stress during the curing process. The formed front cover 22 directly inherits the positioning accuracy of the mold for the drive shaft 211 without subsequent machining adjustment. The sleeve 23, as a connecting component between the drive shaft 211 and the external load, forms a clearance fit between its inner wall and the outer surface of the drive shaft 211. Since the coaxiality error is controlled within the injection molding process tolerance range, radial friction caused by eccentricity during operation is avoided.

[0031] Compared with the prior art, the traditional split front cover 22 needs to separately manufacture the sleeve 23 through machining and then connect it to the motor body 21 by bolts or press-fitting. During the assembly process, the coaxiality of the drive shaft 211 and the sleeve 23 needs to be repeatedly adjusted, resulting in complex processes and easy introduction of human errors. In this solution, through mold integrated positioning, the forming accuracy of the sleeve 23 is directly guaranteed by the injection molding process, eliminating the cumulative error of multi-process assembly and reducing the manual adjustment link at the same time.

[0032] Through the above technical solution, this application solves the problem of eccentric friction between the drive shaft 211 and the sleeve 23 caused by the split installation structure of the traditional motor, avoids the complex operations of repeatedly adjusting the coaxiality during the assembly process, realizes the one-time forming positioning of the installation of the motor assembly 2, improves the stability of the connection structure between the drive shaft 211 and the load, reduces mechanical wear and extends the service life.

[0033] In an implementation manner of this embodiment, it is proposed that the machine shell 1 includes a main shell 11 and a cover plate 12. The main shell 11 has an installation opening and a clamping groove 113 is provided on the side wall of the main shell 11, and a clamping buckle 123 is provided on the cover plate 12; when the cover plate 12 is closed on the installation opening, the clamping buckle 123 is clamped and fixed in the clamping groove 113.

[0034] In this embodiment, the main housing 11 refers to the basic structural member that bears the installation cavity 4. Specifically, it can be realized by stamping and stretching aluminum materials. The card slot 113 provided on its side wall is used to form a mechanical lock with the cover plate 12. The cover plate 12 refers to an independent component that covers the installation opening. Specifically, it can be formed by plastic injection molding. Its buckle 123 is used to form a detachable connection with the card slot 113 of the main housing 11. The card slot 113 refers to the groove structure opened on the side wall of the main housing 11. Specifically, a continuous U-shaped groove design can be adopted to guide the embedding trajectory of the buckle 123. The buckle 123 refers to the convex structure provided at the edge of the cover plate 12. Specifically, a combination form of an elastic arm and a hook-shaped end can be adopted to generate a locking force through deformation.

[0035] Specifically, the main housing 11 and the cover plate 12 adopt a split structure. The installation opening allows the motor assembly 2 to be directly installed into the cavity without reserving an additional assembly channel. The cover plate 12 is fixed by the directional interlock of the buckle 123 and the card slot 113. During the covering process, the buckle 123 slides into the card slot 113 and generates elastic deformation. Finally, the hook-shaped end forms a mechanical lock with the inner wall of the card slot 113. This structure replaces the traditional screw or adhesive fixing method. During operation, only vertical pressure needs to be applied to complete the assembly without auxiliary tools. During maintenance, the cover plate 12 can be disassembled separately by releasing the lock of the buckle 123 by external force, avoiding damage to the structural integrity of the main housing 11.

[0036] Compared with the prior art, the traditional servo motor housing mostly adopts an integral casting or a screw-fixed split structure. The former needs to set a complex assembly channel inside the housing, resulting in an increase in volume. The latter relies on multiple screw connections, increasing the number of parts and the assembly time. This solution realizes quick disassembly and assembly through the one-way interlock mechanism of the buckle 123 and the card slot 113, eliminating the thread processing procedure and tool dependence required for screw fastening while maintaining the structural strength.

[0037] Through the above technical solutions, the present application effectively reduces the number of housing parts and assembly steps. The split design of the main housing 11 and the cover plate 12 enables the maintenance of internal components without overall disassembly of the outer shell 212. The buckle 123 and card slot 113 structure improves the motor assembly efficiency and reduces the maintenance cost while ensuring the connection reliability.

[0038] In an implementation manner of this embodiment, at least one first mounting hole 221 is provided on the side surface of the front cover 22, and the main housing 11 is provided with a second mounting hole 112 that matches the first mounting hole 221. The first mounting hole 221 and the second mounting hole 112 are fixed by pin positioning.

[0039] In this embodiment, the first mounting hole 221 refers to a positioning hole structure provided on the side wall of the front cover 22, which can be specifically implemented by a circular through-hole, a stepped hole or a special-shaped hole, and is used to form a position corresponding relationship with the second mounting hole 112 on the main housing 11. Among them, the second mounting hole 112 refers to a positioning hole structure on the side wall of the main housing 11, which can be specifically implemented by a round hole or a counterbore that matches the size of the first mounting hole 221, and its axis coincides with the axis of the first mounting hole 221 to ensure the positioning accuracy. Among them, the pin positioning and fixing means that a cylindrical or conical metal pin is inserted into the first mounting hole 221 and the second mounting hole 112, and a rigid connection is achieved by the interference fit between the outer wall of the pin and the hole wall, which can be specifically implemented by a stainless steel pin or a cemented carbide pin.

[0040] Specifically, at least one first mounting hole 221 is provided on the side surface of the front cover 22, and a second mounting hole 112 is provided at the corresponding position on the side wall of the main housing 11. During the assembly process, when the front cover 22 is placed into the mounting cavity 4 of the main housing 11, the axes of the first mounting hole 221 and the second mounting hole 112 are automatically aligned, and then the pin is inserted into the hole to complete the fixation. Through the positioning function of at least one pin, the radial displacement between the front cover 22 and the main housing 11 is restricted, and the coaxiality between the drive shaft 211 of the motor main body 21 and the drive through-hole 111 is ensured. Since the contact area between the pin and the hole wall is large, a stable connection state can still be maintained under a vibrating environment, avoiding positioning deviation caused by loosening.

[0041] Compared with the prior art, in a traditional motor, the motor assembly 2 and the housing are mostly connected by screw fastening or snap-fastening 123. The former results in a decrease in positioning accuracy due to the screw clearance, and the latter causes insufficient structural rigidity due to elastic deformation. In this solution, through the interference fit between the pin and the hole position, the influence of the connection clearance on the positioning accuracy is eliminated, and at the same time, the multi-point positioning design effectively suppresses the relative torsion between the front cover 22 and the main housing 11.

[0042] Through the above technical solution, the present application realizes the precise positioning of the front cover 22 and the main housing 11, avoids the problem of motor axis deviation caused by hole position deviation during the assembly process, improves the overall structural rigidity, enables the motor assembly 2 to maintain stable coaxiality during operation, simplifies the assembly process and reduces the risk of connection loosening caused by vibration.

[0043] In an implementation manner of this embodiment, it is proposed that the circuit board assembly 3 includes a first circuit board 31, a second circuit board 32 and a connector 33. The first circuit board 31 is electrically connected to the second circuit board 32, the second circuit board 32 is electrically connected to the motor assembly 2, and the connecting wire bundle of the connector 33 passes through the wire groove of the cover plate 12 and is connected to the first circuit board 31; the first circuit board 31 is arranged in the mounting cavity 4 along the first direction, and the second circuit board 32 is arranged in the mounting cavity 4 along the second direction.

[0044] In this embodiment, the first circuit board 31 refers to a functional module for carrying an external signal interface and a control unit, which can be specifically implemented by a double-sided copper clad laminate. Its arrangement along the first direction can reduce the planar overlapping area with the second circuit board 32. The second circuit board 32 refers to a power module for driving the motor assembly 2, which can be specifically implemented by a four-layer PCB board. Its arrangement along the second direction can shorten the wiring distance from it to the motor assembly 2. The connector 33 refers to a plug for connecting an external wire harness and an internal circuit, which can be specifically implemented by a waterproof terminal. By passing through a wire groove, it can avoid the wire harness from bending inside the cavity. The wire groove refers to a guiding channel opened on the surface of the cover plate 12, which can be specifically implemented by a U-shaped groove structure and is used to restrict the routing of the connecting wire harness. The first direction and the second direction refer to a spatial arrangement that is perpendicular to each other, such as the horizontal and vertical directions. Through the staggered layout, the electromagnetic interference between the circuit boards can be reduced.

[0045] Specifically, the first circuit board 31 is configured to be installed in the top area of the cavity along the horizontal direction, and the second circuit board 32 is configured to be installed in the side wall area of the cavity along the vertical direction. The first circuit board 31 forms a mechanical interlock with the insertion block 321 of the second circuit board 32 through the slot 311, and the pads of the two are in contact to achieve electrical conduction. The wire harness of the connector 33 extends from the outside of the cover plate 12 through the wire groove to the terminal interface of the first circuit board 31, and the external control signal is input to the first circuit board 31 through the wire harness. The second circuit board 32 is directly connected to the power supply pins of the motor assembly 2, and the drive signal is transmitted to the motor after being amplified by the power of the second circuit board 32. Thus, the signal processing module and the power drive module are physically isolated, and the vertical layout of the first circuit board 31 and the horizontal layout of the second circuit board 32 form a spatial stagger, effectively compressing the planar space occupied by the circuit boards.

[0046] Compared with the prior art, traditional servo motors integrate the control and drive functions on a single circuit board, resulting in an overly large circuit board area and the cross-arrangement of signal lines and power lines. In this application, through the dual-circuit board partition design, the high-frequency control signal and the high-current drive signal are separated and transmitted, avoiding the common-ground interference. In the prior art, the external wire harness is directly connected to the motor drive circuit, which is likely to cause confusion in the wire sequence at the interface. However, in this application, through the directional guidance of the connector 33 and the wire groove, the wire harness only extends along a fixed path to the first circuit board 31, simplifying the assembly complexity.

[0047] Through the above technical solutions, this application solves the problem of volume redundancy caused by the circuit board layout in traditional servo motors, improves the utilization rate of the cavity space through a three-dimensional arrangement; reduces the crosstalk between the control signal and the drive signal, and improves the signal transmission stability; the wire harness is centrally guided through the wire groove, reducing the cross-winding of internal cables and improving the connection reliability.

[0048] In an implementation manner of this embodiment, it is proposed that a receiving groove 121 is dug at the upper end of the cover plate 12, at least one positioning pin 122 is arranged in the receiving groove 121, and the first circuit board 31 is provided with a positioning hole 314 matching the positioning pin 122, and the first circuit board 31 is fixed on the cover plate 12 along the positioning pin 122.

[0049] In this implementation manner, the receiving groove 121 refers to a recessed area formed on the upper surface of the cover plate 12 through machining. Specifically, it can be realized by milling or injection molding processes. Its depth matches the thickness of the first circuit board 31 and is used to limit the displacement of the circuit board in the horizontal direction. The positioning pin 122 refers to a columnar protrusion structure arranged in the receiving groove 121. Specifically, it can be made of a metal material or integrally injection molded with the cover plate 12. Its diameter tolerance is controlled within 0.05 mm and is used to form an interference fit with the positioning hole 314. The positioning hole 314 refers to a through hole opened at the edge of the first circuit board 31. Specifically, it can be processed by a laser drilling process. The aperture tolerance is controlled within a range of 0.02 mm, and vertical direction constraint is achieved by sleeving on the positioning pin 122.

[0050] Specifically, during the assembly process, the first circuit board 31 is placed into the receiving groove 121, and three-dimensional space positioning is achieved through the cooperation relationship between the positioning hole 314 and the positioning pin 122. The gap between the side wall of the receiving groove 121 and the edge of the circuit board is controlled within 0.1 mm to eliminate the possibility of lateral displacement. The top end of the positioning pin 122 is designed with a chamfer structure to guide the circuit board for quick alignment. Its height exceeds the surface of the circuit board by 0.5 mm to ensure mechanical interlock after crimping and fixing. In a vibrating environment, the interference fit between the positioning pin 122 and the positioning hole 314 generates contact surface friction force to prevent the relative sliding between the circuit board and the cover plate 12.

[0051] Compared with the prior art, the traditional solution uses multiple screws to lock the circuit board on the housing, which has the problem of sensor offset caused by cumulative assembly errors. This solution improves the positioning accuracy to the micron level through the cooperation structure of the positioning pin 122 and the receiving groove 121, and at the same time eliminates the stress deformation caused by screw locking. In the prior art, the circuit board needs to reserve a screw installation area, resulting in a reduction of about 15% in the effective wiring area. However, in this solution, by canceling the screw installation position, the effective area utilization rate of the circuit board is increased to 98%.

[0052] Through the above technical solution, this application realizes the precise constraint of the circuit board in three-dimensional space, controls the repeat accuracy of the assembly position within a range of ±0.01 mm, and ensures that the Hall sensor 34 and the magnetic sheet 242 maintain a constant gap. Vibration tests show that within the frequency range of 20 - 2000 Hz, the displacement of the circuit board does not exceed 2 microns, and the signal transmission stability is improved to 99.9%. The assembly process is reduced from the original 6 steps to 2 steps, the production efficiency is increased by 40%, and the problem of repair due to screw loosening is avoided.

[0053] In an implementation manner of this embodiment, it is proposed that the first circuit board 31 is further provided with a slot 311, the lower surface of the first circuit board 31 is provided with a first pad 312, the end of the second circuit board 32 is provided with a plug 321, the plug 321 is provided with a second pad 322, and when the second circuit board 32 is plugged into the first circuit board 31, the first pad 312 and the second pad 322 are connected by a welding strip 313; the second circuit board 32 is further provided with a third pad 323 connected to the motor assembly 2.

[0054] Among them, the first pad 312 refers to a conductive area provided on the lower surface of the first circuit board 31, which can be specifically formed by an etching process using copper foil material, and is used to achieve electrical connection with the second circuit board 32, and its surface can be covered with an antioxidant coating to enhance stability.

[0055] The second pad 322 refers to a conductive area provided at the end of the plug 321, which can be specifically processed by a gold plating process, and is used to form a contact surface with the first pad 312, and its thickness can be controlled within the range of 0.1 mm to 0.3 mm to adapt to the welding process.

[0056] The welding strip 313 refers to a conductive medium connecting the first pad 312 and the second pad 322, which can be specifically formed by curing solder paste through a reflow soldering process, and its width can match the pad size to ensure mechanical strength and electrical conductivity.

[0057] The third pad 323 refers to a conductive area provided at the edge of the second circuit board 32, which can be specifically connected to the internal circuit layer through a metallized via, and is used to achieve electrical connection with the wire or connector of the motor assembly 2.

[0058] Specifically, when the first circuit board 31 and the second circuit board 32 are assembled in a vertical plug-in manner, after the plug 321 is inserted into the slot 311, the first pad 312 and the second pad 322 are fixedly connected through the welding strip 313. This connection method does not require additional cables and reduces the space occupied in the horizontal direction. The third pad 323 is provided at the end of the second circuit board 32 and is directly connected to the power supply or signal interface of the motor assembly 2 through a wire, avoiding interference caused by too long a signal transmission path. The welding strip 313 forms a stable mechanical support after curing, and at the same time realizes electrical conduction between the two circuit boards.

[0059] Compared with the prior art, in the traditional servo motor, a single circuit board is horizontally arranged, and the connection between the boards needs to be through flying wires or connectors, which not only occupies space but also is prone to poor contact. This solution integrates the electrical connection and mechanical fixation functions through vertical plug-in and direct welding of pads, effectively reducing the assembly level and at the same time eliminating the impedance mismatch problem introduced by connectors.

[0060] Through the above technical solution, the present application solves the problems of low utilization rate of the layout space of the traditional servo motor circuit board and poor reliability of the connection between boards, realizes the efficient assembly of multi-layer circuits in a limited cavity space, reduces the risk of contact failure, and improves the signal transmission stability at the same time.

[0061] In an implementation manner of this embodiment, it is proposed that the motor assembly 2 is further provided with an induction magnetic group 24. The induction magnetic group 24 includes a fixed seat 241 and a magnetic sheet 242. A connection groove connected to the drive shaft 211 is provided at the upper end of the fixed seat 241, and an installation groove for fixing the magnetic sheet 242 is provided at the lower end of the fixed seat 241; the first circuit board 31 is provided with a Hall sensor 34, and the Hall sensor 34 is arranged axially below the induction magnetic group 24 along the motor assembly 2; the second circuit board 32 is integrally provided with an MCU module, a drive module and a power management module. The power management module is connected to the MCU module, the drive module and the Hall sensor 34, and the MCU module is connected to the drive module and the Hall sensor 34 to control the drive of the motor assembly 2.

[0062] In this implementation manner, the induction magnetic group 24 refers to a magnetic field generating device composed of the fixed seat 241 and the magnetic sheet 242. Specifically, it can be realized by using a polycarbonate injection-molded fixed seat 241 in cooperation with a neodymium iron boron magnetic sheet 242. The fixed seat 241 is rigidly connected to the drive shaft 211 through the connection groove, so that the magnetic sheet 242 rotates synchronously with the drive shaft 211. The Hall sensor 34 refers to a magnetic field induction element, specifically, a linear Hall element can be used, which is arranged axially directly below the magnetic sheet 242 and is used to detect the change in the magnetic field intensity generated when the magnetic sheet 242 rotates. The MCU module refers to a micro control unit, specifically, an ARM Cortex-M series chip can be used, which is integrated on the second circuit board 32 and is used to receive Hall signals and generate PWM control instructions. The drive module refers to a motor power drive circuit, specifically, an H-bridge topology structure can be used, which is used to convert MCU instructions into motor drive current. The power management module refers to a multi-channel power supply distribution circuit, specifically, a combination of a DC-DC buck chip and an LDO can be used to provide stable voltage for the MCU, the drive module and the Hall sensor 34.

[0063] Specifically, the magnetic disk 242 is fixed to the lower end of the fixed seat 241 through the mounting groove. When the drive shaft 211 rotates, it drives the magnetic disk 242 to rotate synchronously, and the magnetic field distribution thereof changes periodically. The Hall sensor 34 is arranged axially below the magnetic disk 242 to directly detect the change in magnetic field intensity and output an analog voltage signal. This signal is subjected to AD conversion and angle calculation by the MCU module to generate the deviation data between the target position and the actual position of the motor. The MCU module calculates the PWM duty ratio parameter according to the deviation data and adjusts the motor winding current through the drive module to form a closed-loop control. The power management module converts the external input voltage into two outputs of 5V and 3.3V, which are respectively supplied to the drive module and the MCU module, and at the same time provides a reference voltage for the Hall sensor 34. Thus, the function integration of position detection, signal processing, power distribution and drive control is realized.

[0064] Compared with the prior art, the traditional potentiometer detects the angle through mechanical contact, and there is a problem of deterioration of linearity caused by contact wear, while the optical encoder relies on optical devices and is easily affected by dust pollution, affecting the accuracy. This solution uses non-contact magnetic field detection to directly collect the rotation information of the magnetic disk 242 through the Hall sensor 34, avoiding mechanical friction and optical pollution interference. In the prior art, the control circuit is distributed in a decentralized manner, and additional wiring is required to connect the sensor, the controller and the drive unit. This solution integrates the MCU module, the drive module and the power management module on a single circuit board, shortening the signal transmission path and eliminating the risk of introducing external interference.

[0065] Through the above technical solutions, this application solves the problem of insufficient feedback accuracy of traditional servo motors. Among them, the Hall sensor 34 directly detects the rotating magnetic field of the magnetic disk 242, and the angle resolution can reach more than 12 bits; the control efficiency is optimized, and the integrated circuit design reduces the signal transmission delay to within 10 μs; the system integration is improved, and the volume of the circuit board assembly 3 is reduced by about 40% compared with the discrete layout, which is suitable for miniaturized devices with limited space.

[0066] Embodiment 3: Based on Embodiment 1 and Embodiment 2, this embodiment specifically further describes the motor assembly 2. Its motor main body 21 includes a drive shaft 211, a magnetic ring 213, a coil, a housing 212, a rear cover 214, a third circuit board 215, a first bearing 216 and a second bearing 217. One end of the housing 212 is connected to the front cover 22 and the other end is connected to the rear cover 214. The coil is fixed to the inner wall of the housing 212. The first bearing 216 is embedded in the first mounting groove in the middle of the front cover 22, and the second bearing 217 is embedded in the second mounting groove in the middle of the rear cover 214. Both ends of the drive shaft 211 are slidably matched with the first bearing 216 and the second bearing 217 respectively. The magnetic ring 213 is sleeved on the drive shaft 211 and is in an inner-outer position correspondence with the coil. The third circuit board 215 is installed on the rear cover 214 and is electrically connected to the coil.

[0067] In this embodiment, the housing 212 refers to the support structure that encloses the internal components of the motor. Specifically, it can be realized by a split high-quality carbon steel housing, which is used to axially fix the front cover 22 and the rear cover 214 and form a sealed cavity. The coil refers to the electromagnetic component formed by winding a wire. Specifically, a flat winding structure can be directly laminated on the inner wall of the housing 212 to shorten the magnetic path distance. The first mounting groove and the second mounting groove refer to the annular grooves for positioning the bearings. Specifically, a stepped inner wall can be formed by numerical control machining to limit the axial displacement of the bearings. The third circuit board 215 is the circuit board for leading out the coil. Specifically, it can be designed as an annular PCB board mounted on the end face of the rear cover 214 to achieve direct connection and welding with the coil terminals. In a specific example, the drive shaft 211 and the magnetic ring 213 are combined into a rotor assembly. Among them, the drive shaft 211 and the magnetic ring 213 can be connected by clearance fit or fixed by glue. The rotor assembly has fewer parts, higher assembly efficiency, and can further reduce the volume and weight of the motor. The coil and the housing 212 form a stator structure. A through hole is also provided at one end of the housing 212 where it is connected to the front cover 22, so that when the front cover 22 of the motor body 21 is injection-molded, injection-molded material is injected into the through hole to increase the stability of the front cover 22 and the motor body 21. In addition, in this embodiment, the coreless brushless motor directly adopts a carbon steel housing + coil, and the coil is directly arranged on the side wall of the housing, so that the motor structure forms a coreless cup structure; compared with the combination of a plastic appearance + a stator core + a coil in the prior art, this application reduces one stator core, which can not only make the motor smaller in volume, but also reduce the weight of the motor.

[0068] Specifically, the housing 212, the front cover 22, and the rear cover 214 are axially fixedly connected by threads or snap fasteners 123 to form a closed housing 212 structure. The coils are arranged radially on the inner wall of the housing 212, and the magnetic ring 213 is coaxially assembled in the middle of the drive shaft 211 and maintains an air gap distance from the coil. Both ends of the drive shaft 211 are inserted into the inner rings of the first bearing 216 and the second bearing 217 respectively to achieve rotational support through rolling friction. The third circuit board 215 is directly connected to the coil lead-out wire through a plug-in terminal, eliminating the sliding contact structure of the traditional brush. When current passes through the coil, the generated alternating magnetic field drives the magnetic ring 213 to drive the drive shaft 211 to rotate, and the third circuit board 215 adjusts the current phase in real time to control the speed.

[0069] In some specific embodiments, the winding wire of the coil can be made of enameled copper wire, for example, with a wire diameter ranging from 0.05 mm to 0.08 mm. The first bearing 216 and the second bearing 217 can be selected as powder metallurgy oil-impregnated bearings, whose outer diameter size is 0.03 - 0.10 mm larger than the opening diameter of the installation groove for press-fitting and fixing. Compared with the prior art, the traditional brushed motor needs to install a commutator on the rotor and cooperate with carbon brushes to achieve current commutation, resulting in an increase in the axial length and mechanical wear. In this solution, the coil is fixed on the inner wall of the housing 212, and the magnetic ring 213 is installed on the drive shaft 211 to form an outer rotor structure. At the same time, the drive shaft 211 is supported by double bearings, eliminating the brush structure and shortening the axial dimension. The direct connection method of the third circuit board 215 to the coil avoids energy loss caused by sliding contact.

[0070] Through the above technical solutions, the present application effectively reduces the axial space occupation of the motor and solves the problem of excessive volume caused by the commutator structure of the traditional brushed motor. The double-bearing support structure enhances the rotational stability of the drive shaft 211 and reduces energy loss caused by shafting vibration. The brushless design eliminates the mechanical friction between the brushes and the commutator, significantly extending the service life of the motor. The direct-connected circuit board layout shortens the current transmission path and improves the power conversion efficiency.

[0071] In an implementation manner of this embodiment, it is proposed that the main housing 11 of the casing 1 is made of an aluminum shell material, and the cover plate 12 of the casing 1 is a plastic part; the winding wire diameter of the coil is less than 0.1 mm, and the resistance value of the coil is 16.4 Ω ± 8%; wherein, the working parameters of the coreless brushless servo motor are set as any one or more of the positioning accuracy ≤ ±1°, the rotation angle is 360°, the working voltage is 4V - 9V, and the working current is less than 650 mA, and the mass of the coreless brushless servo motor ≤ 7 g.

[0072] In this implementation manner, the aluminum shell material means that the main housing 11 is formed by processing aluminum alloy materials, and specifically, it can be realized by stamping and stretching forming or die-casting process. Utilizing its high specific strength characteristics to reduce the structural weight, and at the same time enhancing the overall anti-deformation ability through rigid support.

[0073] Among them, the plastic part means that the cover plate 12 is injection-molded from engineering plastics, and specifically, nylon or polycarbonate materials can be used to simplify the processing difficulty of complex shapes and utilize the insulation of plastics to avoid the risk of circuit short circuits. Among them, the winding wire diameter being less than 0.1 mm means that the coil winding uses ultra-fine copper wires, which can be specifically achieved through precision winding equipment, increasing the number of coil turns within a limited space to enhance the magnetic field density while reducing the occupation of the winding volume on the axial length of the motor. Among them, the resistance value being 16.4Ω±8% refers to the nominal value and allowable deviation range of the coil DC resistance, which is specifically achieved by adjusting the wire diameter, number of turns, and winding process to maintain a stable working current of the motor under the rated voltage and avoid problems such as excessive temperature rise or insufficient driving force.

[0074] Specifically, the main housing 11 reduces the overall weight of the motor through the lightweight characteristics of aluminum, while meeting the structural strength requirements of the motor under dynamic loads; the cover plate 12 is made of plastic parts to achieve low-cost processing of complex wire grooves and buckle 123 structures through injection molding, and uses the insulation characteristics of plastics to isolate the circuit board from the metal housing. The coil winding uses ultra-fine wire diameter wires to achieve a compact layout, thereby reducing the radial size of the motor and copper loss. At the same time, by precisely controlling the coil resistance value range, the motor maintains current stability in high and low temperature environments and avoids risks such as abnormal power or overheating caused by resistance drift.

[0075] Compared with the prior art, the main housing 11 of traditional servo motors usually uses cast iron or steel materials, resulting in excessive weight and high processing costs. This solution achieves a balance between lightweight and high strength through an aluminum shell material; existing coil designs mostly use thick wires with a wire diameter greater than 0.1 mm, resulting in a large winding volume and a wide resistance fluctuation range. This solution optimizes the motor efficiency and thermal management performance through fine wire diameter and precise resistance control.

[0076] This application uses a brushless motor, a magnetic encoder, and servo control to achieve a position positioning accuracy of ≤±1°, a maximum use time of ≤40 ms for a 180° rotation with a 2g load, a fixed point at any angle of 360° absolute position, and a shortest path control position fixed point function. This application can also use a brushless coreless motor + servo control. Under the working voltage of 4V~9V and the rated voltage of 6V±1V, the static current of the motor is <40 mA. At room temperature such as 25°C, the working current is <500 mA. At low temperature such as -45°C, the working current is <650 mA. At high temperature such as 65°C, the working current is <400 mA. This application can also use a brushless coreless motor + an aluminum shell to achieve an overall motor weight of ≤7 g within a limited size of 22.5*8.8*16.5±0.3 mm. This application can also use a brushless coreless motor + servo control to achieve an ultra-long service life with a fault-free operation time of ≥20000H.

[0077] Through the above technical solutions, the present application solves the problems of excessive volume and weight caused by the bulky structure of traditional brushed servo motors. At the same time, by optimizing the coil winding parameters, the copper loss and temperature rise are reduced, the working efficiency of the motor and the long-term operation reliability are improved, and the defects of current overload or driving force decline caused by unreasonable resistance design are avoided.

[0078] The algorithms or displays provided herein are not inherently related to any particular computer, virtual system, or other device. In addition, the embodiments of the present invention are not directed to any particular programming language.

[0079] In the specification provided herein, a large number of specific details are set forth. However, it can be understood that the embodiments of the present invention can be practiced without these specific details. Similarly, in order to streamline the present invention and assist in understanding one or more of the various inventive aspects, in the above description of the exemplary embodiments of the present invention, the various features of the embodiments of the present invention are sometimes grouped together into a single embodiment, figure, or description thereof. Among them, the claims following the specific implementation manner are hereby expressly incorporated into the specific implementation manner, where each claim itself is a separate embodiment of the present invention.

[0080] Those skilled in the art can understand that the modules in the devices in the embodiments can be adaptively changed and arranged in one or more devices different from the embodiments. The modules or units or components in the embodiments can be combined into a module or unit or component, and in addition, they can be divided into multiple sub-modules or sub-units or sub-components. Except that at least some of such features and / or processes or units are mutually exclusive.

[0081] It should be noted that the above embodiments illustrate the present invention rather than limit the present invention, and those skilled in the art can design alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The present invention can be implemented by means of hardware including several different elements and by means of a properly programmed computer. In the unit claims listing several devices, several of these devices can be embodied by the same item of hardware. The use of the words first, second, and third, etc. does not denote any order. These words can be interpreted as names. The steps in the above embodiments, unless otherwise specifically stated, should not be construed as limiting the order of execution.

Claims

1. A coreless brushless servo motor, characterized in that, Comprising: A housing (1) with an internally installed cavity (4). One end face of the housing (1) is provided with a driving through-hole (111), and the driving through-hole (111) is communicated with the installation cavity (4). A motor assembly (2) is arranged in the installation cavity (4). The motor assembly (2) includes a motor main body (21) and a front cover (22) arranged on the motor main body (21). The front cover (22) is provided with a sleeve (23), and the sleeve (23) is arranged on the periphery of the driving shaft (211) of the motor main body (21). And when the front cover (22) is fixed in the installation cavity (4), the sleeve (23) extends out along the driving through-hole (111). And a circuit board assembly (3) is arranged in the installation cavity (4) and is electrically connected to the motor assembly (2). The circuit board assembly (3) is used to drive the motor assembly (2) to work.

2. The coreless brushless servo motor according to claim 1, wherein, The front cover (22) is injection-molded by placing the driving end of the motor main body (21) in an injection mold. After the front cover (22) is injection-molded, the sleeve (23) is coaxially arranged with the driving shaft (211).

3. The coreless brushless servo motor according to claim 1, wherein The housing (1) includes a main housing (11) and a cover plate (12). The main housing (11) has an installation opening and a clamping groove (113) is arranged on the side wall of the main housing (11). The cover plate (12) is provided with a buckle (123). When the cover plate (12) covers the installation opening, the buckle (123) is clamped and fixed in the clamping groove (113).

4. The coreless brushless servo motor according to claim 3, characterized in that, At least one first installation hole (221) is arranged on the side surface of the front cover (22). The main housing (11) is provided with a second installation hole (112) that matches the first installation hole (221). The first installation hole (221) and the second installation hole (112) are positioned and fixed by a pin.

5. The canless brushless servo motor according to claim 3, wherein The circuit board assembly (3) includes a first circuit board (31), a second circuit board (32) and a connector (33). The first circuit board (31) is electrically connected to the second circuit board (32). The second circuit board (32) is electrically connected to the motor assembly (2). The connecting wire bundle of the connector (33) passes through the wire groove of the cover plate (12) and is connected to the first circuit board (31). Wherein, the first circuit board (31) is arranged in the installation cavity (4) along a first direction, and the second circuit board (32) is arranged in the installation cavity (4) along a second direction.

6. The coreless brushless servo motor according to claim 5, wherein A receiving groove (121) is dug at the upper end of the cover plate (12). At least one positioning pin (122) is arranged in the receiving groove (121). The first circuit board (31) is provided with a positioning hole (314) that matches the positioning pin (122). The first circuit board (31) is fixed on the cover plate (12) along the positioning pin (122).

7. The coreless brushless servo motor according to claim 5, wherein, The first circuit board (31) is further provided with a slot (311), and the first circuit board (31) is provided with a first pad (312); one end of the second circuit board (32) is provided with a plug (321) matching the slot (311), and the plug is provided with a second pad (322); when the second circuit board (32) is plugged on the first circuit board (31), the first pad (312) and the second pad (322) are connected by a welding strip (313); the second circuit board (32) is further provided with a third pad (323) connected to the motor assembly.

8. The coreless brushless servo motor according to claim 5, wherein The motor assembly (2) is further provided with an induction magnetic group (24), the induction magnetic group (24) includes a fixed seat (241) and a magnetic sheet (242), the upper end of the fixed seat (241) is provided with a connection groove connected to the drive shaft (211), and the lower end of the fixed seat (241) is provided with a mounting groove for fixing the magnetic sheet (242); the first circuit board (31) is provided with a Hall sensor (34), and the Hall sensor (34) is arranged axially along the motor assembly (2) below the induction magnetic group (24); the second circuit board (32) is integrally provided with an MCU module, a drive module and a power management module, the power management module is connected to the MCU module, the drive module and the Hall sensor (34), and the MCU module is connected to the drive module and the Hall sensor (34) to control the drive of the motor assembly (2).

9. The coreless brushless servo motor according to claim 1, wherein The motor main body (21) includes a housing (212), a drive shaft (211), a magnetic ring (213), a coil, a rear cover (214), a third circuit board (215), a first bearing (216) and a second bearing (217); One end of the housing (212) is connected to the front cover (22) and the other end is connected to the rear cover (214), the coil is arranged on the inner wall of the housing (212), the first bearing (216) is arranged in a first mounting groove in the middle of the front cover (22), the second bearing (217) is arranged in a second mounting groove in the middle of the rear cover (214), both ends of the drive shaft (211) are slidably connected to the first bearing (216) and the second bearing (217), the magnetic ring (213) is arranged on the drive shaft (211) and located inside the coil; the third circuit board (215) is arranged on the rear cover (214) and the third circuit board (215) is electrically connected to the coil.

10. The coreless brushless servo motor according to claim 9, wherein, The main housing (11) of the machine shell is made of aluminum shell material, and the cover plate (12) of the machine shell is a plastic part; the wire diameter of the winding of the coil is less than 0.1 mm, and the resistance value of the coil is 16.4 Ω ± 8%, wherein, the working parameters of the coreless brushless servo motor are set as any one or more of positioning accuracy ≤ ±1°, rotation angle of 360°, working voltage of 4V - 9V, working current less than 650 mA, and the mass of the coreless brushless servo motor ≤ 7 g.

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