Hollow cup brushless servo motor

Abstract

The embodiment of the application relates to the technical field of electric machines, in particular to a hollow-cup brushless servo motor, and solves the problems of traditional brush servo motors, such as bulky size, low efficiency and short service life, and improves the stability of the output end connection through coaxial arrangement of the sleeve and the driving shaft. The application of the brushless motor eliminates the friction loss of the brush, the integrated structure design realizes the miniaturization of the equipment, and the closed mounting cavity effectively protects the internal components from the external environment.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of motor technology, and in particular to a coreless brushless servo motor. Background Art

[0002] Currently, servo motors generally use brushed DC motors as their driving core, combined with potentiometers or photoelectric encoders for position feedback to form a closed-loop control system. This design is widely used in robotics, model aircraft, industrial automation, and other fields, but it has the following inherent drawbacks:

[0003] (1) Volume and weight issues: Brushed motors require built-in brushes and commutator structures, which result in a large axial length and a bulky overall size, making it difficult to meet the needs of modern lightweight equipment.

[0004] (2) Efficiency and life limit: Mechanical friction of the brushes results in high energy loss (efficiency is usually <70%) and is prone to sparking and electromagnetic interference. Brush wear limits the lifespan (typical lifespan is about 50,000 cycles), requiring frequent maintenance.

[0005] (3) Poor concentricity between the motor drive shaft and the casing sleeve: The auxiliary connection sleeve of the existing servo motor is generally set on the casing, which causes a deviation between the casing sleeve and the drive shaft, resulting in low concentricity, affecting the stability of the connection between the motor and the drive equipment. Summary of the Invention

[0006] In view of the above problems, an embodiment of the present invention provides a hollow cup brushless servo motor, which solves the problems of existing brush motors such as large size and weight, high energy loss and short life, and poor concentricity between the motor drive shaft and the casing sleeve.

[0007] In a first aspect, the present invention provides a coreless brushless servo motor, comprising:

[0008] A housing having a built-in mounting cavity, wherein one end surface of the housing is provided with a driving through hole, the driving through hole being connected to the mounting cavity;

[0009] a motor assembly disposed in the mounting cavity, the motor assembly comprising a motor body and a front cover disposed on the motor body, the front cover being provided with a sleeve disposed on a circumferential side of a drive shaft of the motor body; and when the front cover is fixed in the mounting cavity, the sleeve extends along the drive through hole;

[0010] And a circuit board assembly is arranged 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.

[0011] In some optional embodiments, 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 driving shaft.

[0012] In some optional embodiments, the casing includes a main shell and a cover plate, the main shell has an installation opening and a card slot is provided on the side wall of the main shell, and the cover plate is provided with a buckle; when the cover plate covers the installation opening, the buckle is fixed in the card slot.

[0013] In some optional embodiments, the side surface of the front cover is provided with at least one first mounting hole, the main shell is provided with a second mounting hole matching the first mounting hole, and the first mounting hole and the second mounting hole are positioned and fixed by pins.

[0014] In some optional embodiments, 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, and the connecting wiring 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 the first direction, and the second circuit board is arranged in the installation cavity along the second direction.

[0015] In some optional embodiments, a receiving groove is dug at the upper end of the cover plate, at least one positioning pin is provided in the receiving groove, the first circuit board is provided with a positioning hole matching the positioning pin, and the first circuit board is fixed to the cover plate along the positioning pin.

[0016] In some optional embodiments, the first circuit board is also provided with a slot, and the first circuit board is provided with a first solder pad; one end of the second circuit board is provided with an insert matching the slot, and the insert is provided with a second solder pad; when the second circuit board is plugged into the first circuit board, the first solder pad and the second solder pad are connected by a welding strip; the second circuit board is also provided with a third solder pad connected to the motor assembly.

[0017] In some optional embodiments, the motor assembly is further provided with an induction magnetic group, the induction magnetic group includes a fixing seat and a magnetic sheet, the upper end of the fixing seat is provided with a connecting groove connected to the drive shaft, and the lower end of the fixing seat is provided with a mounting groove for fixing the magnetic sheet; the first circuit board is provided with a Hall sensor, and the Hall sensor is arranged below the induction magnetic group along the axial direction of the motor assembly; the second circuit board is integrated 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, and the MCU module is connected to the drive module and the Hall sensor to control the drive of the motor assembly.

[0018] In some optional 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;

[0019] One end of the shell is connected to the front cover and the other end is connected to the rear cover. The coil is arranged on the inner wall of the shell. The first bearing is arranged in the first mounting groove in the middle of the front cover, and the second bearing is arranged in the second mounting groove in the middle of the rear cover. The two ends of the drive shaft are respectively slidably connected to the first bearing and the second bearing. The magnetic ring is arranged on the drive shaft and is located on the inner side of the coil; the third circuit board is arranged on the rear cover and the third circuit board is electrically connected to the coil.

[0020] In some optional embodiments, the main shell of the casing is made of aluminum, and the cover of the casing is a plastic part; the winding wire diameter of the coil is less than 0.1 mm, and the resistance of the coil is 16.4Ω±8%; wherein, the operating parameters of the hollow cup brushless servo motor are set to any one or more of the positioning accuracy ≤±1°, the rotation angle is 360°, the operating voltage is 4V~9V, and the operating current is less than 650mA, and the mass of the hollow cup brushless servo motor is ≤7g.

[0021] The embodiment of the present invention provides a coreless brushless servo motor, which has the following beneficial effects:

[0022] The present invention relates to a coreless brushless servo motor comprising a housing, a motor assembly, and a circuit board assembly. The housing has a built-in mounting cavity, one end of which is provided with a drive through-hole, the drive through-hole being connected to the mounting cavity. The motor assembly is disposed within the mounting cavity and comprises a motor body and a front cover disposed on the motor body. The front cover is provided with a sleeve disposed around the drive shaft of the motor body. When the front cover is secured within the mounting cavity, the sleeve extends along the drive through-hole. The circuit board assembly is disposed within the mounting cavity and electrically connected to the motor assembly, and is used to drive the motor assembly. This design addresses the issues of bulkiness, low efficiency, and short lifespan of conventional brushed servo motors. The coaxial arrangement of the sleeve and the drive shaft improves the stability of the output connection. The use of a brushless motor eliminates brush friction loss, the integrated structural design enables device miniaturization, and the enclosed mounting cavity effectively protects internal components from environmental influences.

[0023] 2. The coreless brushless servo motor of the present invention has a coil winding wire diameter of less than 0.1 mm and a coil resistance of 16.4Ω±8%. This allows the motor to achieve a static current of less than 40 mA, an operating current of less than 500 mA at room temperature (e.g., 25°C), an operating current of less than 650 mA at low temperatures (e.g., -45°C), and a current of less than 400 mA at high temperatures (e.g., 65°C). This significantly reduces the energy consumption of the coreless brushless servo motor, conserving energy and lowering the output requirements of power supply equipment. Furthermore, the coreless brushless servo motor can achieve an exceptionally long lifespan, enabling trouble-free operation for ≥20,000 hours.

[0024] The above description is only an overview of the technical solutions of the embodiments of the present invention. In order to more clearly understand the technical means of the embodiments of the present invention, they can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the embodiments of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are specifically listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings are only used to illustrate the embodiments and are not to be considered as limiting the present invention. In addition, the same reference symbols are used to represent the same components throughout the drawings. In the drawings:

[0026] Figure 1 The structure diagram of the coreless brushless servo motor provided by the present invention is shown;

[0027] Figure 2 An exploded schematic diagram of a coreless brushless servo motor provided by the present invention is shown;

[0028] Figure 3 A cross-sectional schematic diagram of the coreless brushless servo motor provided by the present invention is shown;

[0029] Figure 4 shows a cross-sectional schematic diagram of a motor assembly provided by the present invention;

[0030] Figure 5 An exploded schematic diagram of a circuit board assembly provided by the present invention is shown;

[0031] Figure 6 A cross-sectional schematic diagram of the circuit board assembly provided by the present invention is shown.

[0032] in,

[0033] 1. Casing; 11. Main housing; 111. Drive hole; 112. Second mounting hole; 113. Slot; 12. Cover; 121. Accommodating groove; 122. Positioning pin; 123. Buckle;

[0034] 2. Motor assembly; 21. Motor body; 211. Drive shaft; 212. Housing; 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. Induction magnetic group; 241. Fixing seat; 242. Magnetic sheet;

[0035] 3. Circuit board assembly; 31. First circuit board; 311. Slot; 312. First solder pad; 313. Solder bar; 314. Positioning hole; 32. Second circuit board; 321. Insert; 322. Second solder pad; 323. Third solder pad; 33. Connector; 34. Hall sensor;

[0036] 4. Install the cavity. DETAILED DESCRIPTION

[0037] The exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although 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 to the embodiments set forth herein.

[0038] Example 1:

[0039] Figure 1-6 The present invention shows a first embodiment of a coreless brushless servo motor. The coreless brushless servo motor of the present invention includes a housing 1, a motor assembly 2, and a circuit board assembly 3. The housing 1 has a built-in mounting cavity 4. A drive through-hole 111 is provided on one end face of the housing 1. The drive through-hole 111 is connected to the mounting cavity 4. The motor assembly 2 is disposed in the mounting cavity 4. The motor assembly 2 includes a motor body 21 and a front cover 22 disposed on the motor body 21. The front cover 22 is provided with a sleeve 23. The sleeve 23 is disposed on the circumference of the drive shaft 211 of the motor body 21. When the front cover 22 is fixed in the mounting cavity 4, the sleeve 23 extends along the drive through-hole 111. The circuit board assembly 3 is disposed in the mounting cavity 4 and is electrically connected to the motor assembly 2.

[0040] Among them, the installation cavity 4 refers to the enclosed space inside the casing 1 for accommodating the motor assembly 2 and the circuit board assembly 3. Specifically, it can be realized by a stamping and stretching shell to realize the integrated layout of the components. The driving through hole 111 refers to a circular through hole that passes through the end face of the casing 1. The aperture matches the protruding part of the sleeve 23, which is used to ensure the docking accuracy between the output end of the drive shaft 211 and the external device. The front cover 22 refers to a bearing structure fixed to the end of the motor body 21. Specifically, it can be combined with the motor body 21 by an injection molding process to carry the sleeve 23 and realize the positioning connection with the casing 1. The sleeve 23 refers to a metal tubular structure that is sleeved on the outer periphery of the drive shaft 211. A gap is left between the inner diameter and the drive shaft 211 to protect the drive shaft 211 and improve the coaxiality of the output end connection.

[0041] Specifically, the motor assembly 2 is fixed in the mounting cavity 4 of the housing 1 through the front cover 22, and 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 of the sleeve 23 and the drive shaft 211 is ensured by the injection molding process, so that the connection stability between the output end of the drive shaft 211 and the external device is improved. The circuit board assembly 3 is directly integrated in the mounting 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 mounting 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 hollow cup brushless servo motor can be a brushless servo steering gear, which can be used to drive the antenna to rotate to change the antenna angle.

[0042] Compared to existing technologies, traditional brushed motors require brushes and a commutator, increasing their axial length. The brushless motor employed in this solution eliminates mechanical commutation through electronic commutation. Traditional motors have sleeves 23 mounted on the housing 1, which can result in assembly errors with the motor drive shaft 211. In this solution, sleeves 23 are integrated into the front cover 22 of the motor assembly 2, ensuring concentricity through simultaneous molding. Traditional circuit boards require external mounting, while this solution optimizes space through internal integration.

[0043] Through the above technical solution, this application solves the problems of conventional brushed servo motors, such as bulkiness, low efficiency, and short lifespan. The coaxial arrangement of sleeve 23 and drive shaft 211 also improves the stability of the output connection. The use of a brushless motor eliminates brush friction loss, the integrated structural design enables device miniaturization, and the enclosed mounting cavity 4 effectively protects internal components from external environmental influences.

[0044] Example 2:

[0045] This embodiment is based on the first embodiment, and this embodiment further describes the housing 1, the motor assembly 2 and the circuit board assembly 3 in detail.

[0046] In one implementation of this embodiment, the front cover 22 is injection molded by placing the driving end of the motor body 21 in an injection mold, and after the front cover 22 is injection molded, the sleeve 23 is coaxially arranged with the driving shaft 211.

[0047] In this embodiment, the injection molding process involves using the drive end of the motor body 21 as a mold positioning reference, and injecting a thermoplastic or thermosetting material into the mold to form the front cover 22. Specifically, polyamide, polycarbonate, or reinforced nylon can be used for this purpose. The geometric constraints of the mold are used to ensure that the sleeve 23 and the drive shaft 211 form a fixed spatial relationship. Specifically, the sleeve 23 and the drive shaft 211 are coaxially arranged. This means that during the injection molding process, the mold cavity is positioned using 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 axis offset caused by reference switching during assembly.

[0048] 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 in the circumference of 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 axial direction is orthogonal to the mold parting surface. During the curing process, the injection molding material maintains the coaxial relationship between the sleeve 23 and the drive shaft 211 through shrinkage stress. The molded front cover 22 directly inherits the positioning accuracy of the mold for the drive shaft 211, and no subsequent processing adjustment is required. The sleeve 23 serves as a connecting component between the drive shaft 211 and the external load. Its inner wall forms a clearance fit with the outer surface of the drive shaft 211. The coaxiality error is controlled within the tolerance range of the injection molding process to avoid radial friction caused by eccentricity during operation.

[0049] Compared to existing technologies, the traditional split front cover 22 requires a separate sleeve 23 to be machined and then connected to the motor body 21 via bolts or press-fit. This assembly process requires repeated adjustments to the coaxiality between the drive shaft 211 and the sleeve 23, resulting in a complex process and the potential for human error. This solution, however, utilizes integrated mold positioning to ensure sleeve 23 molding accuracy directly through the injection molding process, eliminating the cumulative errors of multiple assembly steps and reducing manual adjustments.

[0050] Through the above technical solution, the present 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 complicated operation of repeatedly adjusting the coaxiality during the assembly process, realizes the one-time molding positioning of the motor assembly 2 installation, improves the stability of the connection structure between the drive shaft 211 and the load, reduces mechanical wear and extends the service life.

[0051] In one implementation of this embodiment, it is proposed that the casing 1 includes a main shell 11 and a cover plate 12, the main shell 11 has an installation opening and the side wall of the main shell 11 is provided with a card slot 113, and the cover plate 12 is provided with a buckle 123; when the cover plate 12 covers the installation opening, the buckle 123 is snap-fitted and fixed in the card slot 113.

[0052] In this embodiment, the main shell 11 refers to the basic structural component that supports the installation cavity 4, which can be specifically realized by aluminum stamping and stretching. The card groove 113 provided on the side wall is used to form a mechanical lock with the cover 12. The cover 12 refers to an independent component that covers the installation opening, which can be specifically realized by plastic injection molding, and the clip 123 is used to form a detachable connection with the card groove 113 of the main shell 11. The card groove 113 refers to the groove structure provided on the side wall of the main shell 11, which can specifically adopt a continuous U-shaped groove design to guide the clip 123 to embed into the trajectory. The clip 123 refers to the raised structure provided on the edge of the cover 12, which can specifically adopt a combination of an elastic arm and a hook-shaped end to generate a locking force through deformation.

[0053] Specifically, the main housing 11 and the cover 12 adopt a split structure, and the installation opening allows the motor assembly 2 to be directly installed into the cavity without reserving an additional assembly channel. The cover 12 is fixed by the directional interlocking of the buckle 123 and the slot 113. During the covering process, the buckle 123 slides along the slot 113 and produces elastic deformation, and finally the hook-shaped end forms a mechanical lock with the inner wall of the slot 113. This structure replaces the traditional screw or adhesive fixing method. During operation, only vertical pressure is required to complete the assembly, and no auxiliary tools are required. During maintenance, the buckle 123 can be released by external force to remove the cover 12 separately to avoid damaging the structural integrity of the main housing 11.

[0054] Compared to existing technologies, traditional servo motor housings often use either one-piece castings or separate, screw-fastened structures. The former requires complex assembly channels within the housing, increasing its size, while the latter relies on multiple screw connections, increasing the number of parts and consuming assembly time. This solution utilizes a one-way interlocking mechanism between the buckle 123 and the slot 113, enabling quick assembly and disassembly while maintaining structural strength, eliminating the threading process and tooling required for screw fastening.

[0055] Through the above technical solution, the present application effectively reduces the number of housing parts and assembly steps. The split design of the main housing 11 and cover 12 allows maintenance of internal components without disassembling the entire housing 212. The buckle 123 and slot 113 structure ensures connection reliability while improving motor assembly efficiency and reducing maintenance costs.

[0056] In one implementation of this embodiment, at least one first mounting hole 221 is provided on the side of the front cover 22, and the main shell 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 positioned and fixed by pins.

[0057] In this embodiment, the first mounting hole 221 refers to a positioning hole structure provided on the side wall of the front cover 22, and can be implemented by a circular through hole, a stepped hole, or a special-shaped hole, and is used to form a positional correspondence 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, and can be implemented by a circular hole or a countersunk hole 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 positioning accuracy. Among them, pin positioning and fixation refers to inserting a cylindrical or conical metal pin into the first mounting hole 221 and the second mounting hole 112, and utilizing the interference fit between the outer wall of the pin and the hole wall to achieve a rigid connection. Specifically, it can be implemented by using a stainless steel pin or a carbide pin.

[0058] Specifically, at least one first mounting hole 221 is provided on the side of the front cover 22, and a second mounting hole 112 is provided at a 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 pins are inserted into the holes to complete the fixation. Through the positioning effect of at least one pin, the radial displacement between the front cover 22 and the main housing 11 is constrained, and the coaxiality between the drive shaft 211 of the motor body 21 and the drive through hole 111 is ensured. Due to the large contact area between the pin and the hole wall, a stable connection state can still be maintained in a vibration environment, avoiding positioning deviation caused by loosening.

[0059] Compared to existing technologies, conventional motors often use threaded fastening or snap-fit ​​fasteners 123 to connect the motor assembly 2 to the housing. The former reduces positioning accuracy due to thread play, while the latter suffers from insufficient structural rigidity due to elastic deformation. This solution eliminates the impact of connection play on positioning accuracy through an interference fit between the pins and holes. Furthermore, the multi-point positioning design effectively suppresses relative torsion between the front cover 22 and the main housing 11.

[0060] Through the above technical solution, the present application achieves precise positioning of the front cover 22 and the main shell 11, avoids the problem of motor axis deviation caused by hole position deviation during the assembly process, improves the overall structural rigidity, and enables the motor assembly 2 to maintain stable coaxiality during operation. At the same time, it simplifies the assembly process and reduces the risk of loose connections due to vibration.

[0061] In one implementation 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 wiring harness of the connector 33 is connected to the first circuit board 31 through the wire groove of the cover plate 12; the first circuit board 31 is arranged in the installation cavity 4 along the first direction, and the second circuit board 32 is arranged in the installation cavity 4 along the second direction.

[0062] 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 implemented by a double-layer copper-clad laminate. Its arrangement along the first direction can reduce the planar overlap 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 implemented by a four-layer PCB board. Its arrangement along the second direction can shorten the wiring distance with the motor assembly 2. The connector 33 refers to a connector for connecting the external wiring harness with the internal circuit, which can be implemented by a waterproof terminal. The wiring harness can be prevented from bending in the cavity by passing it through a wire trough. The wire trough refers to a guide channel opened on the surface of the cover plate 12, which can be implemented by a U-shaped groove structure, which is used to constrain the direction of the connecting wire harness. The first direction and the second direction refer to mutually perpendicular spatial arrangements, such as the horizontal and vertical directions. The electromagnetic interference between circuit boards can be reduced by the staggered layout.

[0063] Specifically, the first circuit board 31 is configured to be installed in the top area of ​​the cavity in the horizontal direction, and the second circuit board 32 is configured to be installed in the side wall area of ​​the cavity in the vertical direction. The first circuit board 31 forms a mechanical interlock with the plug 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 wiring harness of the connector 33 extends from the outside of the cover 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 wiring harness. The second circuit board 32 is directly connected to the power pin of the motor assembly 2, and the drive signal is transmitted to the motor after being power-amplified by the second circuit board 32. As a result, 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 staggered space, which effectively compresses the plane space occupied by the circuit board.

[0064] Compared with the existing technology, traditional servo motors use a single circuit board to integrate control and drive functions, resulting in an excessively large circuit board area and cross-arrangement of signal lines and power lines. The present application uses a dual-circuit board partition design to separate the transmission of high-frequency control signals and high-current drive signals, avoiding common ground interference. In the existing technology, the external wiring harness is directly connected to the motor drive circuit, which can easily cause confusion in the wiring sequence at the interface. However, the present application uses the directional guidance of the connector 33 and the wire trough to ensure that the wiring harness only extends along a fixed path to the first circuit board 31, simplifying the assembly complexity.

[0065] Through the above technical solution, this application solves the volume redundancy problem caused by the circuit board layout in traditional servo motors, and improves the cavity space utilization through three-dimensional arrangement; reduces the crosstalk between the control signal and the drive signal, and improves the signal transmission stability; the wiring harness is centrally guided through the wire trough to reduce the cross-entanglement of internal cables and improve the connection reliability.

[0066] In one implementation of this embodiment, it is proposed that a accommodating groove 121 is dug at the upper end of the cover plate 12, at least one positioning pin 122 is provided in the accommodating 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.

[0067] In this embodiment, the accommodating groove 121 refers to a recessed area formed by machining on the upper surface of the cover plate 12, which can be achieved by milling or injection molding. Its depth matches the thickness of the first circuit board 31 and is used to limit the horizontal displacement of the circuit board. The locating pin 122 refers to a columnar protrusion structure provided in the accommodating groove 121. It can be made of metal or injection molded integrally with the cover plate 12. Its diameter tolerance is controlled within 0.05 mm and is used to form an interference fit with the locating hole 314. The locating hole 314 refers to a through hole opened at the edge of the first circuit board 31. It can be processed by laser drilling technology, with a hole diameter tolerance controlled within 0.02 mm. Vertical constraint is achieved by being sleeved on the locating pin 122.

[0068] Specifically, during the assembly process, the first circuit board 31 is placed in the receiving groove 121, and three-dimensional spatial positioning is achieved through the cooperation 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 of the positioning pin 122 is designed with a chamfered structure to guide the circuit board to quickly align. Its height exceeds the surface of the circuit board by 0.5 mm to ensure mechanical interlocking after crimping and fixing. In a vibration environment, the interference fit between the positioning pin 122 and the positioning hole 314 generates contact surface friction, preventing the circuit board and the cover plate 12 from sliding relative to each other.

[0069] Compared to existing solutions, which use multiple screws to secure the circuit board to the housing, this solution presents the problem of cumulative assembly errors leading to sensor offset. This solution, through the coordinated structure of locating pins 122 and accommodating slots 121, improves positioning accuracy to micrometers while eliminating stress and deformation caused by screw locking. Existing solutions require a reserved area for screw mounting on the circuit board, reducing the effective wiring area by approximately 15%. By eliminating the screw mounting area, this solution increases the effective circuit board area utilization to 98%.

[0070] Through the above technical solution, this application achieves precise constraint of the circuit board in three-dimensional space, controlling the assembly position repeatability within ±0.01 mm, and ensuring a constant gap between the Hall effect sensor 34 and the magnetic plate 242. Vibration tests show that within the frequency range of 20-2000 Hz, the circuit board displacement does not exceed 2 microns, and the signal transmission stability is improved to 99.9%. The assembly process has been reduced from six steps to two, increasing production efficiency by 40% and avoiding the problem of rework caused by loose screws.

[0071] In one implementation of this embodiment, it is proposed that the first circuit board 31 is also provided with a slot 311, a first soldering pad 312 is provided on the lower surface of the first circuit board 31, an insert block 321 is provided at the end of the second circuit board 32, and the insert block 321 is provided with a second soldering pad 322. When the second circuit board 32 is plugged into the first circuit board 31, the first soldering pad 312 and the second soldering pad 322 are connected by a welding strip 313; the second circuit board 32 is also provided with a third soldering pad 323 connected to the motor assembly 2.

[0072] Among them, the first solder pad 312 refers to a conductive area arranged on the lower surface of the first circuit board 31, which can be formed by copper foil material through an etching process to achieve electrical connection with the second circuit board 32. Its surface can be covered with an anti-oxidation coating to enhance stability.

[0073] The second pad 322 is a conductive area disposed at the end of the plug 321 , which may be gold-plated to form a contact surface with the first pad 312 . The thickness of the second pad 322 may be controlled within a range of 0.1 mm to 0.3 mm to accommodate the welding process.

[0074] The welding bar 313 refers to a conductive medium connecting the first pad 312 and the second pad 322 , and can be formed by curing solder paste through a reflow process. The width of the welding bar 313 can match the pad size to ensure mechanical strength and conductive performance.

[0075] The third solder pad 323 refers to a conductive area arranged at the edge of the second circuit board 32 , which can be connected to the internal circuit layer through a metallized through-hole and is used to achieve electrical connection with the wires or connectors of the motor assembly 2 .

[0076] Specifically, when the first circuit board 31 and the second circuit board 32 are assembled using a vertical plug-in method, after the plug block 321 is inserted into the slot 311, the first solder pad 312 and the second solder pad 322 are fixedly connected via the soldering bar 313. This connection method does not require additional cables, reducing horizontal space usage. The third solder pad 323 is located 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 via a wire, avoiding interference caused by an excessively long signal transmission path. After curing, the soldering bar 313 forms a stable mechanical support and simultaneously achieves electrical conductivity between the two circuit boards.

[0077] Compared to existing technologies, this invention uses a single horizontally arranged servo motor circuit board. Connecting the boards requires flying leads or connectors, which not only takes up space but also can lead to poor contact. This solution integrates electrical connection and mechanical fastening through vertical plug-in connection and direct soldering to pads, effectively reducing the number of assembly layers and eliminating the impedance mismatch introduced by connectors.

[0078] Through the above technical solution, this application solves the problems of low space utilization and poor reliability of inter-board connections in traditional servo motor circuit board layouts, realizes efficient assembly of multi-layer circuits in a limited cavity space, reduces the risk of contact failure, and improves signal transmission stability.

[0079] In one implementation of this embodiment, it is proposed that the motor assembly 2 is also provided with an induction magnetic group 24, the induction magnetic group 24 includes a fixing seat 241 and a magnetic piece 242, the upper end of the fixing seat 241 is provided with a connecting groove connected to the drive shaft 211, and the lower end of the fixing seat 241 is provided with a mounting groove for fixing the magnetic piece 242; the first circuit board 31 is provided with a Hall sensor 34, and the Hall sensor 34 is axially arranged below the induction magnetic group 24 of the motor assembly 2; the second circuit board 32 is integrated 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.

[0080] In this embodiment, the induction magnetic assembly 24 refers to a magnetic field generating device consisting of a fixed base 241 and a magnetic plate 242. Specifically, the fixed base 241 can be formed of polycarbonate injection molded material and combined with a neodymium iron boron magnetic plate 242. The fixed base 241 is rigidly connected to the drive shaft 211 via a connecting slot, allowing the magnetic plate 242 to rotate synchronously with the drive shaft 211. The Hall sensor 34 refers to a magnetic field sensing element, specifically a linear Hall element. It is axially arranged directly below the magnetic plate 242 and is used to detect changes in magnetic field intensity generated by the rotation of the magnetic plate 242. The MCU module refers to a microcontroller unit, specifically an ARM Cortex-M series chip, integrated on the second circuit board 32, and is used to receive Hall signals and generate PWM control commands. The driver module refers to the motor power drive circuit, specifically an H-bridge topology, which converts MCU commands into motor drive current. The power management module refers to a multi-channel power distribution circuit, specifically a DC-DC step-down chip combined with an LDO, providing stable voltage for the MCU, driver module, and Hall sensor 34.

[0081] Specifically, magnetic disc 242 is secured to the lower end of mounting base 241 via a mounting slot. When drive shaft 211 rotates, magnetic disc 242 rotates synchronously, causing its magnetic field distribution to change periodically. A Hall effect sensor 34 is axially positioned below magnetic disc 242, directly detecting changes in magnetic field strength and outputting an analog voltage signal. This signal undergoes A / D conversion and angle calculation in the MCU module, generating data indicating the deviation between the motor's target and actual positions. The MCU module calculates the PWM duty cycle parameters based on this deviation data and regulates the motor winding current through the drive module, creating a closed-loop control system. The power management module converts the external input voltage into two outputs, 5V and 3.3V, which are supplied to the drive module and MCU module, respectively, while also providing a reference voltage for Hall effect sensor 34. This integrates position detection, signal processing, power distribution, and drive control.

[0082] Compared to existing technologies, traditional potentiometers detect angles through mechanical contact, which can lead to linearity degradation due to contact wear. Photoelectric encoders rely on optical components, making them susceptible to dust contamination and accuracy loss. This solution uses non-contact magnetic field detection, directly collecting information about the rotation of magnetic disk 242 via Hall effect sensor 34, thus avoiding interference from mechanical friction and optical contamination. In existing technologies, control circuits are distributed, requiring additional wiring to connect sensors, controllers, and drive units. This solution integrates the MCU module, drive module, and power management module onto a single circuit board, shortening the signal transmission path and eliminating the risk of external interference.

[0083] Through the above technical solution, the present application solves the problem of insufficient feedback accuracy of traditional servo motors, wherein the Hall sensor 34 directly detects the rotating magnetic field of the magnetic sheet 242, and the angular resolution can reach more than 12 bits; the control efficiency is optimized, and the integrated circuit design reduces the signal transmission delay to less than 10μs; 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.

[0084] Example 3:

[0085] Based on Examples 1 and 2, this embodiment further describes the motor assembly 2. The motor 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. The housing 212 is connected to the front cover 22 at one end and to the rear cover 214 at the other end. The coil is fixed to the inner wall of the housing 212. The first bearing 216 fits into a first mounting groove in the middle of the front cover 22, and the second bearing 217 fits into a second mounting groove in the middle of the rear cover 214. The first and second bearings 216 and 217 slide in contact with each other at both ends of the drive shaft 211, respectively. The magnetic ring 213 is sleeved on the drive shaft 211, forming an inner and outer position corresponding to the coil. The third circuit board 215 is mounted on the rear cover 214 and electrically connected to the coil.

[0086] In this embodiment, the housing 212 is the support structure that encloses the internal components of the motor. Specifically, it can be constructed of a split, high-quality carbon steel housing. It serves to axially secure the front cover 22 and rear cover 214, forming a sealed cavity. The coil is an electromagnetic component wound with a wire. Specifically, a flat winding structure can be directly laminated onto the inner wall of the housing 212 to shorten the magnetic path. The first and second mounting slots are annular grooves used to position the bearings. Specifically, the inner walls can be formed into stepped shapes through CNC machining to limit axial displacement of the bearings. The third circuit board 215 is the circuit board that leads to the coils. Specifically, it can be designed as a ring-shaped PCB mounted on the end surface of the rear cover 214, enabling direct soldering to the coil terminals. In one specific example, the drive shaft 211 and magnetic ring 213 form a rotor assembly. The drive shaft 211 and magnetic ring 213 can be connected by a clearance fit or glue. This rotor assembly has fewer parts, improves assembly efficiency, and further reduces the size and weight of the motor. The coil and housing 212 form the stator structure. A through hole is also provided at one end where the housing 212 is connected to the front cover 22, so that when the motor body 21 is molded with the front cover 22, the molding material is injected into the through hole, thereby increasing the stability of the front cover 22 and the motor body 21. In addition, in this embodiment, the hollow cup brushless motor directly adopts a carbon steel housing + coil, so that the coil is directly arranged on the side wall of the housing, so that the motor structure forms a hollow cup structure; compared with the combination of plastic exterior + stator core + coil in the prior art, this application reduces one stator core, which not only makes the motor smaller, but also reduces the weight of the motor.

[0087] Specifically, the housing 212 is axially fixedly connected to the front cover 22 and the rear cover 214 through threads or snaps 123, forming 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 with the coils. The two ends of the drive shaft 211 are respectively inserted into the inner rings of the first bearing 216 and the second bearing 217, and rotational support is achieved through rolling friction. The third circuit board 215 is directly connected to the coil lead wire through a plug-in terminal, eliminating the sliding contact structure of the traditional brush. When current passes through the coil, the alternating magnetic field generated 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.

[0088] In some specific embodiments, the winding wire of the coil can be made of enameled copper wire, for example, with a wire diameter range of 0.05mm to 0.08mm. The first bearing 216 and the second bearing 217 can use powder metallurgy oil-containing bearings, the outer diameter of which is 0.03~0.10mm larger than the opening diameter of the mounting slot for press-fitting and fixing. Compared with the prior art, traditional brushed motors require a commutator to be installed on the rotor and used in conjunction with carbon brushes to achieve current commutation, resulting in an increase in axial length and mechanical wear. This solution forms an outer rotor structure by fixing the coil to the inner wall of the housing 212 and installing the magnetic ring 213 on the drive shaft 211. At the same time, dual bearings are used to support the drive shaft 211, thereby eliminating the brush structure and shortening the axial dimension. The way in which the third circuit board 215 is directly connected to the coil avoids energy loss caused by sliding contact.

[0089] Through the above technical solution, this application effectively reduces the axial space occupied by the motor, solving the problem of excessive size caused by the commutator structure of traditional brushed motors. The dual-bearing support structure enhances the rotational stability of the drive shaft 211 and reduces energy loss caused by shaft vibration. The brushless design eliminates mechanical friction between the brushes and the commutator, significantly extending the motor's service life. The direct-connect circuit board layout shortens the current transmission path and improves power conversion efficiency.

[0090] In one implementation of this embodiment, the main housing 11 of the housing 1 is made of aluminum, and the cover 12 of the housing 1 is made of plastic. The coil wire diameter is less than 0.1 mm, and the coil resistance is 16.4Ω±8%. The operating parameters of the coreless brushless servo motor are set to any one or more of the following: positioning accuracy ≤±1°, rotation angle 360°, operating voltage 4V-9V, and operating current less than 650mA. The mass of the coreless brushless servo motor is ≤7g.

[0091] In this embodiment, the aluminum shell material means that the main shell 11 is formed by processing aluminum alloy material, which can be specifically achieved by stamping, stretching or die-casting technology, and its high specific strength characteristics are used to reduce the structural weight, while the overall deformation resistance is improved through rigid support.

[0092] Among them, the plastic part refers to the cover plate 12 that is injection molded with engineering plastics, which can be specifically made of nylon or polycarbonate materials. This simplifies the processing difficulty of complex shapes and uses the insulation of plastics to avoid the risk of circuit short circuits. Among them, the winding wire diameter is less than 0.1mm, which means that the coil winding uses ultra-fine copper wire. This can be achieved through precision winding equipment. The number of coil turns is increased in a limited space to increase the magnetic field density, while reducing the winding volume's share of the motor's axial length. Among them, the resistance value of 16.4Ω±8% refers to the nominal value and allowable deviation range of the coil's DC resistance, which is achieved by adjusting the wire diameter, number of turns, and winding process, so that the motor maintains a stable operating current at rated voltage to avoid problems such as excessive temperature rise or insufficient driving force.

[0093] Specifically, the main housing 11 leverages the lightweight properties of aluminum to reduce the motor's overall weight while meeting the motor's structural strength requirements under dynamic loads. The cover 12 is constructed of plastic, using an injection molding process to cost-effectively manufacture the complex wire slots and clips 123. The plastic's insulating properties also isolate the circuit board from the metal housing. The coil windings utilize ultra-fine wire for a compact arrangement, reducing the motor's radial dimensions and copper losses. Precisely controlling the coil resistance range ensures current stability in both high and low temperature environments, preventing power anomalies or overheating risks caused by resistance drift.

[0094] Compared with the existing technology, the main housing 11 of the traditional servo motor is usually made of cast iron or steel, which results in excessive weight and high processing cost. The present solution achieves a balance between lightness and high strength through the aluminum shell material; the existing coil design mostly uses thick wires with a wire diameter greater than 0.1mm, resulting in a large winding volume and a wide resistance fluctuation range. The present solution optimizes the motor efficiency and thermal management performance through fine wire diameter and precise control of resistance.

[0095] This application uses a brushless motor, magnetic encoder, and servo control to achieve positioning accuracy of ≤±1°, a maximum use time of ≤40ms for 180° rotation with a 2g load, 360° absolute position at any angle, and shortest path control position positioning function. This application can also use a brushless hollow cup motor + servo control. Under the conditions of operating voltage: 4V~9V and rated voltage 6V±1V, the motor static current is less than 40mA, the operating current is less than 500mA at room temperature such as 25°C, the operating current is less than 650mA at low temperatures such as -45°C, and the operating current is less than 400mA at high temperatures such as 65°C. This application can also use a brushless hollow cup motor + aluminum housing to achieve an overall motor weight of ≤7g within the limited size of 22.5*8.8*16.5±0.3mm. This application can also use a brushless hollow cup motor + servo control to achieve an ultra-long life and a trouble-free operation time of ≥20,000 hours.

[0096] Through the above technical solution, this application solves the problem of excessive volume and weight of traditional brushed servo motors due to their bulky structure. At the same time, by optimizing the coil winding parameters, copper loss and temperature rise are reduced, the motor's working efficiency and long-term operation reliability are improved, and the defects of current overload or reduced driving force caused by unreasonable resistance design are avoided.

[0097] 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.

[0098] In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the present invention may be practiced without these specific details. Similarly, in order to streamline the present invention and aid in understanding one or more of the various inventive aspects, in the above description of exemplary embodiments of the present invention, various features of embodiments of the present invention are sometimes grouped together into a single embodiment, figure, or description thereof. The claims that follow the detailed description are hereby expressly incorporated into that detailed description, with each claim itself serving as a separate embodiment of the present invention.

[0099] Those skilled in the art will appreciate that the modules in the devices of the embodiments can be adaptively changed and installed in one or more devices different from the embodiments. The modules, units, or components in the embodiments can be combined into one module, unit, or component, and furthermore, they can be divided into multiple submodules, subunits, or subcomponents. Except that at least some of such features and / or processes or units are mutually exclusive.

[0100] It should be noted that the above embodiments illustrate rather than limit the invention, and that alternative embodiments may be devised by a person skilled in the art without departing from the scope of the appended claims. In the claims, any reference signs placed between brackets should not be construed as limiting the claims. 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 may be implemented by means of hardware comprising several different elements and by means of appropriately programmed computers. In a unit claim enumerating several means, several of these means may be embodied by the same item of hardware. The use of the words first, second, and third etc. does not indicate any order. These words may be interpreted as names. The steps in the above embodiments should not be understood as limiting the order of execution unless otherwise specified.

Claims

1. A coreless brushless servo motor, characterized in that: include: A housing (1) having a built-in mounting cavity (4), wherein one end surface of the housing (1) is provided with a driving through hole (111), and the driving through hole (111) is connected to the mounting cavity (4); A motor assembly (2) is arranged in the mounting cavity (4), the motor assembly (2) comprising a motor body (21) and a front cover (22) arranged on the motor body (21), the front cover (22) being provided with a sleeve (23), the sleeve (23) being arranged on the circumference of the drive shaft (211) of the motor body (21); and when the front cover (22) is fixed in the mounting cavity (4), the sleeve (23) extends along the drive through hole (111); and a circuit board assembly (3), arranged in the mounting cavity (4) and electrically connected to the motor assembly (2), the circuit board assembly (3) being used to drive the motor assembly (2) to operate; Wherein, the housing (1) comprises a main shell (11) and a cover plate (12); The circuit board assembly (3) comprises a first circuit board (31), a second circuit board (32) and a connector (33), wherein 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 a connecting wire harness of the connector (33) passes through a 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.

2. The coreless brushless servo motor according to claim 1, characterized in that: The front cover (22) is injection-molded by placing the driving end of the motor body (21) in an injection mold, and 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, characterized in that: The main housing (11) has a mounting opening and a side wall of the main housing (11) is provided with a card slot (113), and the cover plate (12) is provided with a card buckle (123); when the cover plate (12) covers the mounting opening, the card buckle (123) is fixed in the card slot (113).

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

5. The coreless brushless servo motor according to claim 1, characterized in that: An accommodating groove (121) is excavated at the upper end of the cover plate (12), at least one positioning pin (122) is provided in the accommodating groove (121), 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 to the cover plate (12) along the positioning pin (122).

6. The coreless brushless servo motor according to claim 1, characterized in that: The first circuit board (31) is further provided with a slot (311), and the first circuit board (31) is provided with a first soldering pad (312); an end portion of the second circuit board (32) is provided with an insert block (321) matching the slot (311), and the insert block is provided with a second soldering pad (322); when the second circuit board (32) is plugged into the first circuit board (31), the first soldering pad (312) and the second soldering pad (322) are connected via a soldering bar (313); the second circuit board (32) is further provided with a third soldering pad (323) connected to the motor assembly.

7. The coreless brushless servo motor according to claim 1, characterized in that: The motor assembly (2) is further provided with an induction magnetic group (24), the induction magnetic group (24) comprising a fixing seat (241) and a magnetic sheet (242), the upper end of the fixing seat (241) being provided with a connection groove connected to the drive shaft (211), and the lower end of the fixing seat (241) being provided with a mounting groove for fixing the magnetic sheet (242); the first circuit board (31) being provided with a Hall sensor (34), and the Hall sensor (34) being provided below the induction magnetic group (24) along the axial direction of the motor assembly (2); the second circuit board (32) being integrated with an MCU module, a drive module and a power management module, the power management module being connected to the MCU module, the drive module and the Hall sensor (34), and the MCU module being connected to the drive module and the Hall sensor (34) to control the driving of the motor assembly (2).

8. The coreless brushless servo motor according to claim 1, characterized in that: The motor body (21) comprises 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) respectively; the magnetic ring (213) is arranged on the drive shaft (211) and is located on the inner side of 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.

9. The coreless brushless servo motor according to claim 8, characterized in that: The main shell (11) of the housing is made of aluminum, and the cover (12) of the housing is a plastic part; the winding wire diameter of the coil is less than 0.1 mm, and the resistance of the coil is 16.4Ω±8%. The operating parameters of the hollow cup brushless servo motor are set to any one or more of the following: positioning accuracy ≤±1°, rotation angle 360°, operating voltage 4V~9V, and operating current less than 650mA. The mass of the hollow cup brushless servo motor is ≤7g.

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