An external encoder type external brushless motor

Abstract

This utility model relates to the field of brushless motor technology, and in particular discloses an external encoder-type external rotary brushless motor, including an encoder shaft fixed to an external structure, a stator unit, an encoder assembly, a bearing assembly, and a rotor unit mounted on the encoder shaft. The rotor unit is rotatably mounted on the encoder shaft via the bearing assembly. The stator unit is located within the inner cavity of the rotor unit, and the stator unit drives the rotor unit to rotate. The rotor unit is equipped with an encoding detection structure, and the encoder assembly engages non-contactly with the encoding detection structure to detect the rotational position information of the rotor unit. This motor combines an external rotary structure with an external encoder. The external rotary design provides high output torque, the encoder provides accurate non-contact detection, the dual bearings support stable operation, the heat dissipation structure is highly efficient, and the installation adaptability is strong. It achieves a balance between power and control precision, making it suitable for high-torque, high-precision applications, and improving operational reliability and service life.

Description

Technical Field

[0001] This utility model relates to the field of brushless motor technology, and in particular discloses an external encoder type external rotary brushless motor. Background Technology

[0002] Traditional external brushless motors often suffer from wear due to the contact between the encoder and rotor, resulting in poor detection stability, short lifespan, and limited encoder versatility. Furthermore, unreasonable rotor structure design leads to uneven magnetic field distribution, low driving force and efficiency, and poor heat dissipation, affecting high-load operation. Improper support bearing placement can cause poor rotational stability and excessive vibration. The power output structure is complex with low adaptability, and insufficient encoder installation precision results in large detection errors. The encoder shaft end is prone to wear, has poor connection reliability, and fails to provide stable support for various components, making it unsuitable for high-precision positioning scenarios. Utility Model Content

[0003] In order to overcome the shortcomings and deficiencies of the existing technology, the purpose of this utility model is to provide an external encoder type external brushless motor.

[0004] To achieve the above objectives, this utility model provides an external encoder-type external rotary brushless motor, comprising an encoder shaft fixed to an external structure, a stator unit disposed on the encoder shaft, an encoder assembly, a bearing assembly, and a rotor unit. The rotor unit is rotatably mounted on the encoder shaft via the bearing assembly. The stator unit is located within the inner cavity of the rotor unit. The stator unit drives the rotor unit to rotate. The rotor unit is provided with an encoding detection structure. The encoder assembly and the encoding detection structure are non-contactly engaged to detect the rotational position information of the rotor unit.

[0005] This structure avoids mechanical wear and improves detection stability and lifespan by non-contactly engaging the encoder assembly with the rotor unit. The external rotor design keeps the stator fixed, reducing the load on rotating parts and improving operating efficiency. The encoder shaft is fixed to the external structure, ensuring the encoder assembly is securely installed and the rotor position is accurately detected. This makes it suitable for scenarios requiring high-precision positioning. At the same time, non-contact detection reduces maintenance needs, enhances the reliability and durability of motor operation, and the overall structure is compact with high space utilization.

[0006] Furthermore, along the axial direction of the encoder shaft, the encoder assembly is located inside the rotor unit or on one side of the rotor unit; the encoder assembly includes an encoder bracket mounted on the encoder shaft and an external encoder mounted on the encoder bracket, the encoder bracket being hollow inside and mounted on the encoder shaft, and the external encoder being one of a magnetic encoder, an inductive encoder, an optical encoder, and a Hall encoder.

[0007] The encoder assembly uses an encoder bracket to fix the external encoder, ensuring its positional stability, reducing vibration impact, and improving detection accuracy. The encoder bracket is hollow and mounted on the encoder shaft, achieving a compact assembly with the encoder shaft while providing ample space for shaft movement. This avoids structural interference affecting the smooth operation of the motor. At the same time, the hollow design reduces the weight of the bracket itself, reducing the additional load on the motor and further improving overall operational stability. Multiple types of external encoders are available to adapt to different application scenarios, enhancing motor versatility. The encoder bracket design allows for more flexible encoder installation, facilitating position adjustments as needed and ensuring accurate fit with the encoding detection structure. The variety of encoder types also simplifies selection and meets the requirements of different environments.

[0008] Furthermore, when the external encoder is a photoelectric encoder, the rotor unit is provided with a reflective code disk or a transparent grid that cooperates with the photoelectric encoder; when the external encoder is a magnetic encoder or a Hall encoder, the encoding detection structure is a magnetic ring or an inductive magnet that cooperates with it; when the external encoder is an inductive encoder, the encoding bracket is a stator PCB, and the encoding detection structure is a rotor PCB that cooperates with the stator PCB and the inductive encoder.

[0009] Corresponding detection structures are configured for different types of external encoders. Optical encoders are paired with reflective code disks or transparent grids, magnetic and Hall encoders are adapted with magnetic rings or inductive magnets, and inductive encoders are matched with stator PCBs and rotor PCBs. This achieves precise matching between the encoder and the detection structure, significantly improving the stability and accuracy of the detection signal. This targeted design allows each encoder to fully perform under the adapted structure, ensuring detection accuracy in different scenarios and enhancing the motor's adaptability to complex environments through structural synergy. At the same time, it reduces compatibility issues caused by improper selection, further improving the motor's versatility and reliability.

[0010] Furthermore, the rotor unit includes an end cover sleeved on the bearing assembly, heat dissipation protrusions disposed on the outer edge of the end cover, a rotating housing, and multiple permanent magnets disposed on the inner wall of the rotating housing. The multiple permanent magnets are arranged around the stator unit, and the heat dissipation protrusions include multiple protrusions disposed on the outer edge of the end cover.

[0011] The rotor unit's end cover and rotating housing are combined to form a stable structure that facilitates the installation of permanent magnets. The permanent magnets surround the stator to improve magnetic field utilization and enhance driving force. The heat dissipation convex teeth increase the heat dissipation area, accelerate heat dissipation, and prevent the motor from overheating. The multiple convex teeth are evenly distributed, resulting in balanced heat dissipation and improving the motor's continuous operation capability. The structural design of the rotating housing and end cover also enhances the overall rigidity of the rotor, reduces operating vibration, and extends service life.

[0012] Furthermore, the bearing assembly includes two parallel supporting bearings, the stator unit is located between the two supporting bearings, and the end cover includes a rotating component sleeved on the two supporting bearings; the rotating component has an inner ring and an outer ring, a fan blade structure is provided between the inner ring and the outer ring, and the permanent magnet is disposed on the outer ring.

[0013] Two parallel support bearings enhance the stability of the rotor unit's rotation and reduce radial runout. The stator is located in the middle, resulting in more even force distribution and improved operational stability. The rotating parts of the end cover are fitted with bearings to ensure smooth rotation. The fan structure generates airflow as the rotor rotates, accelerating internal heat dissipation. The design of the inner and outer rings strengthens the rotating parts. The permanent magnet is located on the outer ring to optimize the magnetic field distribution and improve motor output efficiency. The overall structure balances stability and heat dissipation.

[0014] Furthermore, the fan blade structure has multiple arc-shaped centrifugal blades, which are arranged around the central axis of the encoding shaft.

[0015] The arc-shaped centrifugal blades are arranged around the encoder shaft, which can efficiently guide the airflow as the rotor rotates, enhance the heat dissipation effect, and accelerate the removal of heat from the motor. The arc-shaped design of the blades reduces wind resistance and energy loss. The even distribution of multiple blades makes the airflow more stable, avoids local overheating, improves the uniformity of heat dissipation, and thus ensures the stable operation of the motor under high load and extends its service life.

[0016] Furthermore, the inner ring of one of the rotating components protrudes axially away from the stator unit along the encoder shaft to form a pulley, and the end of the encoder shaft away from the other rotating component is provided with a key portion. The encoder assembly is fixed to the key portion and disposed adjacent to the other rotating component.

[0017] The inner ring of the rotating part protrudes into a pulley, which facilitates transmission connection with external equipment, simplifies the power output structure, and improves adaptability. The key at the end of the encoder shaft facilitates the fixing of the encoder assembly, ensuring its accurate position. The adjacent rotating part shortens the detection distance and improves the position detection accuracy. The structure design at both ends enables the motor to output power stably and detect position accurately, enhancing the overall functionality and practicality.

[0018] Furthermore, the multiple permanent magnets are arranged in a ring around the central axis of the encoding shaft.

[0019] Multiple permanent magnets are arranged in a ring around the encoder shaft, which makes the magnetic field distribution more uniform and the electromagnetic force between the stator and rotor more balanced, reducing vibration and noise during operation. The ring arrangement improves the utilization rate of the magnetic field, enhances the output torque and efficiency of the motor, and facilitates installation and positioning, ensuring the precise position of the permanent magnets, avoiding magnetic field deviation from affecting performance, making the motor run more smoothly and with lower energy consumption.

[0020] Furthermore, the encoder bracket is provided with an irregularly shaped hole adapted to the encoder shaft and a receiving cavity for accommodating an external encoder. The opening of the receiving cavity faces the encoder detection structure of the rotor unit, and the irregularly shaped hole and the central axis of the functional receiving cavity are coaxially arranged.

[0021] The irregularly shaped holes of the encoder bracket are adapted to the encoder shaft to ensure a stable installation and prevent loosening from affecting the detection. The accommodating cavity precisely accommodates the external encoder, with the opening facing the encoder detection structure to shorten the detection distance and improve signal transmission efficiency. The coaxial arrangement of the two ensures that the detection axis is consistent, reduces detection errors, and improves position detection accuracy. The overall design enhances the installation stability and detection accuracy of the encoder assembly.

[0022] Furthermore, each end of the encoding shaft is provided with a bushing, and the bushing is fixed to the encoding shaft by a shaft key and / or a pin.

[0023] The encoder shaft is equipped with bushings at both ends, which are fixed by shaft keys and / or pins to enhance the connection strength between the bushings and the encoder shaft and prevent relative rotation. The bushings protect the ends of the encoder shaft, reduce wear during installation and use, and extend the life of the shaft. Multiple fixing methods are available to adapt to different stress scenarios, improve connection reliability, ensure the overall structural stability of the encoder shaft, and provide solid support for all components of the motor.

[0024] The beneficial effects of this utility model are as follows: This off-axis encoder-type external rotary brushless motor has a compact structure. The encoder and rotor engage in a non-contact manner, avoiding wear, improving detection stability and lifespan, adapting to high-precision positioning scenarios, and reducing maintenance requirements. The encoder assembly is fixed by a bracket, with multiple types available to enhance versatility and installation flexibility. Corresponding detection structures are configured for different encoders to improve detection accuracy and stability. The rotor unit structure is robust, with permanent magnets arranged in a ring to optimize the magnetic field, enhancing driving force and efficiency. The heat dissipation convex teeth and fan blade structure enhance heat dissipation, ensuring high-load operation. Dual support bearings improve rotational stability and reduce vibration. The inner ring of the rotating component protrudes to form a pulley for easy transmission, and the keyed shaft secures the encoder to ensure accurate detection. The encoder bracket design enhances installation stability and detection accuracy. The bushings at both ends of the encoder shaft are fixed in multiple ways, improving connection reliability, protecting the shaft, and providing stable support for all components. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the overall structure of an external encoder type external brushless motor according to this utility model; Figure 2 This is an exploded view of the present invention; Figure 3 This is a schematic diagram of the encoder assembly of this utility model; Figure 4 This is a partial structural schematic diagram of the rotating unit of this utility model.

[0026] The reference numerals in the attached drawings include: 1. Encoder shaft; 2. Stator unit; 3. Encoder assembly; 4. Rotor unit; 5. Encoder bracket; 6. External encoder; 7. End cover; 8. Heat dissipation serration; 9. Rotating housing; 11. Rotating component; 12. Centrifugal blade; 13. Pulley; 14. Shaft key; 15. Accommodating cavity; 16. Irregular hole; 17. Bushing; 18. Support bearing. Detailed Implementation

[0027] To further illustrate the technical means and effects adopted by this utility model in order to achieve the intended utility model purpose, the following detailed description of the specific implementation methods, structure, features and effects of this utility model is provided in conjunction with the accompanying drawings and preferred embodiments.

[0028] Please see Figures 1 to 4 As shown, this utility model discloses an external encoder-type external brushless motor, including an encoder shaft 1 fixed on an external structure, a stator unit 2 disposed on the encoder shaft 1, an encoder assembly 3, a bearing assembly, and a rotor unit 4. The rotor unit 4 is rotatably mounted on the encoder shaft 1 through the bearing assembly. The stator unit 2 is located in the inner cavity of the rotor unit 4. The stator unit 2 drives the rotor unit 4 to rotate. The rotor unit 4 is provided with an encoding detection structure. The encoder assembly 3 and the encoding detection structure are non-contactly engaged to detect the rotational position information of the rotor unit 4.

[0029] Stator unit 2 is fixed on encoder shaft 1. When three-phase alternating current is applied to its windings, a rotating magnetic field is generated. This rotating magnetic field interacts with the permanent magnet in the inner cavity of rotor unit 4, forming an electromagnetic torque, which drives rotor unit 4 to rotate around encoder shaft 1 via bearing assembly. During this process, the bearing assembly not only provides stable support for rotor unit 4, but also significantly reduces frictional resistance during rotation, ensuring that rotor unit 4 achieves efficient and smooth rotation under the electromagnetic drive of stator unit 2. This external rotation structure allows for a larger rotor rotation radius and can output greater torque, making it suitable for scenarios requiring high torque drive.

[0030] The motor's position detection relies on the cooperation between the encoder assembly 3 and the encoder detection structure of the rotor unit 4. When the rotor unit 4 rotates, its encoder detection structure (usually a component with specific textures or magnetic poles) rotates synchronously with the rotor. The encoder assembly 3 monitors the position changes of the encoder detection structure in real time through non-contact methods (such as photoelectric sensing or magnetoelectric sensing). Since the encoder assembly 3 is relatively fixed to the encoder shaft 1, it can accurately capture the position information of the rotor unit 4, such as its rotation angle, speed, and phase. This information is converted into electrical signals and fed back to the control system. The control system then adjusts the current phase of the stator windings based on the feedback position information to ensure that the rotating magnetic field and the rotor permanent magnet always maintain the optimal angle of action, achieving closed-loop precise control of the motor and ensuring the stability and speed regulation accuracy of the motor operation.

[0031] Specifically, along the axial direction of the encoder shaft 1, the encoder assembly 3 is located in the inner cavity of the rotor unit 4 or on one side of the rotor unit 4; the encoder assembly 3 includes an encoder bracket 5 disposed on the encoder shaft 1 and an external encoder 6 disposed on the encoder bracket 5. The encoder bracket 5 is hollow inside and is mounted on the encoder shaft 1. The external encoder 6 is one of a magnetic encoder, an inductive encoder, an optical encoder, and a Hall encoder.

[0032] The off-axis encoder, also known as a hollow encoder, has a hollow center, allowing shafts, cables, or other components to pass through directly. It is suitable for applications requiring through-mounting, saving space and simplifying design. In this motor, the off-axis encoder is encoder assembly 3, and its structural design directly determines the accuracy and stability of position detection. The encoder bracket 5 is fixed to the encoder shaft 1, providing a stable mounting base for the external encoder 6 and ensuring it remains relatively stationary with respect to the stator unit 2. When the rotor unit 4 rotates, its encoding detection structure moves synchronously with the rotor. The external encoder 6 (magnetic, inductive, optical, or Hall encoder) forms a stable detection distance with the encoding detection structure through the positioning of the encoder bracket 5. For example, a magnetic encoder uses a magnetic sensing element to detect changes in the magnetic field of the detection structure; an optical encoder uses a photoelectric sensor to capture the light transmission / blocking signal of the detection structure; and a Hall encoder relies on a Hall element to sense periodic changes in magnetic field strength. These designs allow non-contact detection to avoid mechanical wear and maintain signal continuity during high-speed rotation.

[0033] The signal processing and feedback of the external encoder 6 constitute a key link in the closed-loop control of the motor. Different types of encoders convert detected position changes into pulse signals or digital codes, which are transmitted to the control system through lines. Based on the frequency and phase of the signals, the control system calculates the speed, angle, and absolute position of the rotor unit 4 in real time, and then dynamically adjusts the current timing of the stator windings. For example, when the rotor speed deviates from the set value, the control system corrects the speed of the rotating magnetic field by changing the current frequency; when the position signal shows a phase deviation, the current phase is immediately adjusted to maintain the optimal electromagnetic torque. This real-time response mechanism, combined with the detection stability provided by the encoder bracket 5, enables the motor to maintain precise speed control and position positioning even under load changes or at high speeds, fully leveraging the high torque advantage of the external rotor structure.

[0034] Specifically, when the external encoder 6 is a photoelectric encoder, the rotor unit 4 is provided with a reflective code disk or a light-transmitting grid that cooperates with the photoelectric encoder; when the external encoder 6 is a magnetic encoder or a Hall encoder, the rotor unit 4 is provided with a magnetic ring or a sensing magnet that cooperates with it; when the external encoder 6 is an inductive encoder, the encoding bracket 5 is a stator PCB, and the encoding detection structure is a rotor PCB that cooperates with the stator PCB and the inductive encoder.

[0035] When the external encoder 6 is a photoelectric encoder, the reflective code disk or transparent grid on the rotor unit 4 will rotate synchronously with the rotor. The light emitted by the photoelectric encoder shines on the code disk or grid. Due to the alternating distribution of reflective and non-reflective areas of the code disk and transparent and opaque parts of the grid, a periodically changing light signal is generated during rotation. The encoder's receiving element converts the light signal into an electrical pulse signal. The rotation angle and speed of the rotor can be calculated by the number and frequency of the pulses, thereby achieving real-time monitoring of the rotor position.

[0036] If the external encoder 6 is a magnetic encoder or a Hall encoder, the magnetic ring or induction magnet on the rotor unit 4 will generate a specific magnetic field distribution. When the rotor rotates, the magnetic field changes with the position of the magnetic ring or magnet. The magnetic encoder converts the periodic changes in magnetic field strength into electrical signals, while the Hall encoder uses a Hall element to sense the changes in magnetic field and generate a Hall voltage, which in turn outputs a pulse signal. The changing patterns of these electrical signals correspond to the rotor rotation state, thereby enabling the measurement of rotor motion parameters. When the external encoder 6 is an inductive encoder, the inductive encoder is set as an encoder IC on the stator PCB. The stator PCB and the rotor PCB of the rotor unit 4 form a coupling structure. When the rotor rotates, the relative position changes of the two will cause the inductance to change periodically. By detecting the electrical signal converted from the inductance change, the rotor rotation information can be reflected.

[0037] Specifically, the rotor unit 4 includes an end cover 7 sleeved on the bearing assembly, heat dissipation protrusions 8 disposed on the outer edge of the end cover 7, a rotating housing 9, and a plurality of permanent magnets disposed on the inner wall of the rotating housing 9. The plurality of permanent magnets are arranged around the stator unit 2, and the heat dissipation protrusions 8 include a plurality of protrusions disposed on the outer edge of the end cover 7.

[0038] In actual use, along the axial direction of the encoder shaft 1, the encoder assembly 3 can be located on both sides of the end cover 7. Along the radial direction of the encoder shaft 1, when the encoder assembly 3 is located on the side away from the stator unit, the encoder assembly 3 is not located in the inner cavity of the rotating housing 9. At this time, the encoder assembly 3 is generally located outside the rotor unit along the axial direction of the encoder shaft 1. When the encoder assembly 3 is located on the side close to the stator unit, the encoder assembly 3 is located in the inner cavity of the rotating housing 9.

[0039] The core structure of rotor unit 4 is designed around power output and stable operation. End cap 7, as a basic component, is mounted on the bearing assembly, providing both rotational connection to the encoder shaft 1 and mounting support for the outer heat dissipation serrations 8 and the rotating housing 9. Multiple permanent magnets on the inner wall of the rotating housing 9 are arranged in a ring around the stator unit 2. When the stator windings generate a rotating magnetic field, the permanent magnets and the rotating magnetic field produce an electromagnetic force, driving the rotating housing 9 to rotate the entire rotor unit 4 synchronously. This ring-shaped layout ensures uniform magnetic field interaction, reduces vibration during rotation, and improves the stability of power output. The alternating polarity of the permanent magnets creates a continuous torque with the stator magnetic field, which is the key power source for the rotor's efficient rotation.

[0040] The design of the heat dissipation serrations 8 and the rotating housing 9 ensures the long-term reliable operation of the motor. Multiple serrations on the outer edge of the end cover 7 make full contact with the air during rotor rotation, increasing the heat dissipation area and accelerating heat dissipation. This effectively removes the heat generated by the permanent magnets and stator windings during operation, preventing high temperatures from affecting the performance of magnetic materials and the insulation of the windings. The rotating housing 9 not only provides fixed protection for the permanent magnets but also drives the surrounding airflow during rotation, creating a synergistic heat dissipation effect with the heat dissipation serrations 8, further enhancing the heat dissipation performance. Simultaneously, the overall structure of the rotor unit 4 maintains stable concentricity during rotation, ensuring accurate relative positioning between the encoding detection structure (such as reflective code disks, magnetic rings, etc.) and the encoder assembly 3. This provides a stable physical basis for position detection and ensures the accuracy of the motor control signals.

[0041] Specifically, the bearing assembly includes two parallel support bearings 18, the stator unit 2 is located between the two support bearings 18, and the end cover 7 includes a rotating member 11 sleeved on the two support bearings 18; the rotating member 11 has an inner ring and an outer ring, and a fan blade structure is provided between the inner ring and the outer ring, and the permanent magnet is provided on the outer ring.

[0042] Two parallel support bearings 18 in the bearing assembly are the core support structure for the stable rotation of the rotor unit 4. They cooperate with the encoder shaft 1 and the rotating component 11 of the end cover 7, respectively, forming a double-support mode. This effectively disperses the radial and axial forces generated during rotor rotation, preventing eccentricity or wobbling of the rotor due to uneven force distribution. Since the stator unit 2 is located between the two support bearings 18, this layout maintains a uniform air gap between the permanent magnets of the stator and rotor, ensuring stable magnetic field interaction, reducing torque fluctuations caused by uneven air gap, and improving the smoothness of motor operation. The low-friction characteristics of the support bearings 18 further reduce the energy loss of rotor rotation, and together with the structural design of the rotating component 11, lay the foundation for efficient motor operation.

[0043] The rotating part 11 of the end cover 7 is fitted onto two support bearings 18 via an inner ring, while the outer ring is used to fix the permanent magnet. This structure, with its separate inner and outer rings, ensures the stability of the permanent magnet rotating synchronously with the outer ring, and also achieves relative rotation with the encoder shaft 1 through the cooperation of the inner ring and the bearings. The fan structure between the inner and outer rings is a key heat dissipation enhancement design. When the rotor rotates, the fan rotates synchronously with the rotating part 11, actively drawing in external cool air and forming a directional airflow. When the airflow flows over the stator windings and the surface of the permanent magnet, it can quickly remove heat. At the same time, the airflow generated by the fan and the heat dissipation protrusions 8 on the outer edge of the end cover 7 work together to accelerate the diffusion of heat to the external environment, effectively control the internal temperature of the motor, avoid demagnetization of the permanent magnet or deterioration of winding performance due to high temperature, and ensure the reliability of the motor during long-term high-load operation.

[0044] Specifically, the fan blade structure has multiple arc-shaped centrifugal blades 12, which are arranged around the central axis of the coding shaft 1.

[0045] In the fan blade structure, multiple arc-shaped centrifugal blades 12 are arranged around the central axis of the encoder shaft 1. This design works efficiently with the rotor's rotational characteristics. When the rotor unit 4 drives the rotating component 11 to rotate, the arc-shaped blades rotate synchronously with the rotating component 11. Their arc-shaped contours guide airflow along the blade surface, using centrifugal force to throw the air inside the blades outwards. Because the blades are evenly distributed around the central axis, a symmetrical airflow field is formed during rotation, avoiding local airflow turbulence and ensuring that air is stably pushed from inside the motor to the outside, quickly carrying away the heat generated by the stator windings and permanent magnets. Compared with traditional straight blades, this centrifugal design can generate a larger air volume at the same speed, improving heat dissipation efficiency. Furthermore, the arc-shaped structure reduces the resistance of airflow as it passes through the blades, reducing additional energy consumption caused by ventilation.

[0046] The surrounding arrangement of multiple centrifugal blades 12 enhances the synergistic heat dissipation effect with the heat dissipation serrations 8. As the airflow generated by the rotating blades is ejected outwards, it comes into full contact with the heat dissipation serrations 8 on the outer edge of the end cover 7. As the airflow passes through the gaps between the serrations, it accelerates heat exchange on the serration surfaces. Simultaneously, the surrounding layout ensures that the airflow evenly covers the entire heat dissipation area, avoiding heat dissipation dead zones and ensuring balanced temperature across all parts of the motor. This structural design allows the fan blades to actively dissipate heat while the rotor rotates, eliminating the need for an additional power source. This saves space and improves the overall efficiency of the heat dissipation system by optimizing the airflow path, providing a reliable guarantee for the stable operation of the motor under high load conditions.

[0047] Specifically, the inner ring of one of the rotating parts 11 protrudes axially away from the stator unit 2 along the encoder shaft 1 to form a pulley 13, and the end of the encoder shaft 1 away from the other rotating part 11 is provided with a key portion 14. The encoder assembly 3 is fixed to the key portion 14 and is disposed adjacent to the other rotating part 11.

[0048] The inner ring of the rotating component 11, extending axially away from the stator unit 2 along the encoder shaft 1 to form the pulley 13, is a key structure for the motor's power output. When the rotor unit 4 rotates under electromagnetic force, the pulley 13 rotates synchronously with the rotating component 11. Through friction or meshing with the external drive belt, it transmits the torque generated by the motor to the load equipment (such as a conveyor belt, fan, etc.). This protruding design maintains an axial distance between the pulley 13 and core components such as the stator unit 2 and bearing assemblies, preventing vibration during power transmission from interfering with the precision structure inside the motor. Simultaneously, the position of the pulley 13 facilitates docking with external equipment of different sizes, improving the motor's installation adaptability. Furthermore, the belt drive has buffering and shock-absorbing characteristics, reducing the impact of load fluctuations on the motor and protecting the stator windings and permanent magnets from instantaneous overload.

[0049] The key portion 14, located at the end of the encoder shaft 1 furthest from the other rotating component 11, provides a precise and stable mounting reference for the encoder assembly 3. The key restricts the relative rotation between the encoder assembly 3 and the encoder shaft 1, ensuring they remain absolutely stationary, which is fundamental to accurate position detection. The proximity of the encoder assembly 3 to the other rotating component 11 minimizes the distance to the encoding detection structure on the rotor unit 4, reducing signal attenuation or interference during transmission and ensuring real-time capture of rotor position changes. For example, when the rotor drives the magnetic ring or reflective code disk to rotate, the nearby encoder can respond to position changes more quickly, producing a clearer and more stable electrical signal. The rigid connection of the key portion 14 combined with the close proximity layout allows the encoder assembly 3 to withstand vibrations during motor operation while accurately feeding back rotor dynamics, providing reliable data support for real-time adjustments in the control system and further improving motor control accuracy.

[0050] Specifically, the multiple permanent magnets are arranged in a ring around the central axis of the encoding axis 1.

[0051] Multiple permanent magnets are arranged in a ring around the central axis of the encoder shaft 1, which is the core design to ensure the efficient electromagnetic drive of the motor. This ring layout allows the permanent magnets to form a closed circumferential magnetic field on the inner wall of the rotating housing 9 of the rotor unit 4. The polarities of adjacent permanent magnets are arranged alternately (e.g., N pole and S pole are distributed in sequence), ensuring that the magnetic field is evenly distributed in the circumferential direction. When alternating current is applied to the three-phase windings of the stator unit 2 to generate a rotating magnetic field, a symmetrical and continuous electromagnetic force is formed between the rotating magnetic field and the ring-arranged permanent magnets. Each permanent magnet is evenly stressed, enabling the rotor unit 4 to obtain a stable torque output, avoiding torque fluctuations caused by uneven magnetic field distribution, and reducing vibration and noise during motor operation.

[0052] Meanwhile, the air gap magnetic field formed by the annularly arranged permanent magnets and stator unit 2 is closer to a sinusoidal waveform, which can effectively reduce high-order harmonic losses and improve the motor's operating efficiency. This structure allows the magnetic lines of force of the permanent magnets to pass through the stator windings evenly in the radial direction, maximizing the utilization of magnetic field energy and making the electromagnetic conversion efficiency of the stator windings higher. In addition, the annular arrangement makes it easy to adjust the number and size of the permanent magnets according to the motor's power requirements, and to adapt to different speed and torque requirements by optimizing the number of pole pairs. At the same time, the annular structure itself has good mechanical stability and can withstand greater centrifugal force when the rotor rotates at high speed, preventing the permanent magnets from falling off due to uneven force and ensuring the long-term reliable operation of the motor.

[0053] Specifically, the encoder bracket 5 is provided with a shaped hole 16 adapted to the encoder shaft 1 and a receiving cavity 15 for accommodating the external encoder 6. The opening of the receiving cavity 15 faces the encoder detection structure of the rotor unit 4, and the shaped hole 16 is coaxially arranged with the central axis of the functional receiving cavity 15.

[0054] The irregularly shaped hole 16 of the encoder bracket 5 is adapted to the encoder shaft 1. This structural design ensures a stable connection and precise positioning between the encoder bracket 5 and the encoder shaft 1. The non-circular contour (such as square, hexagonal, etc.) of the irregularly shaped hole 16 can closely match the corresponding shape of the encoder shaft 1, restricting the relative rotation between the two and keeping the encoder bracket 5 absolutely stationary with the encoder shaft 1. At the same time, the irregularly shaped hole 16 is coaxially set with the central axis of the receiving cavity 15, ensuring the concentricity of the external encoder 6 and the encoder shaft 1 within the receiving cavity 15. This ensures that the detection center of the encoder is completely coincident with the rotation center of the rotor unit 4, eliminating detection errors caused by eccentricity from a mechanical structure perspective and laying the foundation for accurate position detection. This coaxial design ensures that the encoder is always directly opposite the rotor rotation trajectory, avoiding signal distortion caused by detection angle offset.

[0055] The accommodating cavity 15, with its opening facing the rotor unit 4, is a key layout for achieving efficient non-contact detection. The accommodating cavity 15 provides a closed and fixed installation space for the external encoder 6, protecting it from external environmental factors such as dust and moisture. Simultaneously, the opening directly aligns with the encoding detection structure (such as a magnetic ring or reflective code disk), shortening the detection path and enhancing signal strength and stability. For example, when the external encoder 6 is a photoelectric encoder, the opening of the accommodating cavity 15 ensures direct light onto the reflective code disk; if it is a magnetic encoder, the opening direction enhances the sensitivity of magnetic field sensing. This structural design allows the encoder assembly 3, fixed by the encoder bracket 5, to stably capture the position change signal of the rotor unit 4, while also minimizing detection errors through precise mechanical positioning, ultimately improving the response speed and accuracy of the motor's closed-loop control.

[0056] Specifically, each end of the encoding shaft 1 is provided with a bushing 17, and the bushing 17 is fixed to the encoding shaft 1 by a shaft key and / or a pin.

[0057] The bushings 17 at both ends of the encoder shaft 1 are fixed to the encoder shaft 1 by shaft keys and / or pins, forming a double-stable connection structure. The shaft key is embedded in the keyway of the encoder shaft 1 and the bushing 17, restricting their relative rotation through mechanical engagement and ensuring that the bushing 17 remains stationary synchronously with the encoder shaft 1; the pin passes through the corresponding pin hole of the bushing 17 and the encoder shaft 1, further strengthening the axial positioning and preventing the bushing 17 from sliding axially along the encoder shaft 1 during motor operation. This combined fixing method can resist the vibration and impact generated during rotor rotation, prevent loosening between the bushing 17 and the encoder shaft 1, provide rigid support for the encoder shaft 1, ensure its positional stability during motor operation, and thus ensure that the installation reference of fixed components such as the stator unit 2 and encoder assembly 3 does not shift.

[0058] The bushing 17 also optimizes the force distribution and installation adaptability of the encoder shaft 1. The bushings 17 at both ends increase the contact area between the encoder shaft 1 and the external fixed structure, dispersing the radial and axial forces borne by the encoder shaft 1, reducing deformation of the encoder shaft 1 caused by long-term stress, and protecting precision structures such as the key 14 from damage. Simultaneously, the bushings 17 can be designed with different external dimensions according to external installation requirements, allowing the encoder shaft 1 to adapt to various fixing scenarios and improving the installation flexibility of the motor. Furthermore, the bushings 17 provide a protective wrap around both ends of the encoder shaft 1, reducing the intrusion of dust, oil, and other impurities into the bearing assembly or encoder assembly 3, indirectly ensuring smooth rotor rotation and accurate position detection, and providing auxiliary support for the overall stable operation of the motor.

[0059] The working principle of this utility model: The core working mechanism of this off-axis encoder-type external rotating brushless motor revolves around the synergy of electromagnetic drive and precise detection. When the motor starts, three-phase alternating current is applied to the windings of the stator unit 2 to generate a rotating magnetic field, which interacts with the permanent magnets arranged in a ring on the inner wall of the rotor unit 4 to form an electromagnetic torque, driving the rotor to rotate around the encoder shaft 1 through the bearing assembly. The double support bearing 18 ensures smooth rotor rotation, and the external rotating structure outputs high torque with a larger rotation radius. The outer ring of the rotating component 11 drives the permanent magnets to move synchronously, and the inner ring cooperates with the bearing to ensure concentricity. The bushing 17 is fixed to both ends of the encoder shaft 1 by a shaft key and a pin, which strengthens the overall rigidity and is suitable for external installation. The pulley 13 efficiently transmits the rotational power to the load. The fan blades generate centrifugal airflow as the rotor rotates, which works in conjunction with the heat dissipation convex teeth 8 to dissipate heat and maintain a stable motor operating temperature.

[0060] The closed-loop control of the motor relies on the precise coordination between the encoder assembly 3 and the rotor position detection. The encoder bracket 5 is fixed to the encoder shaft 1 through the irregular hole 16. The external encoder 6 inside the accommodating cavity 15 corresponds non-contactly with the rotor's encoding detection structure. Optical encoders use optical signals from reflective code disks or transparent grids, while magnetic encoders use changes in the magnetic field of a magnetic ring to capture rotor position information in real time. The key portion 14 of the encoder shaft 1 ensures that the encoder assembly 3 is stationary and concentric. The detection signal is converted into an electrical signal and fed back to the control system, which adjusts the stator current phase according to the signal to maintain the optimal angle of action between the rotating magnetic field and the permanent magnet. The dual bearing support and coaxial design eliminate mechanical errors, and the rigid fixation of the bushing 17 and the encoder bracket 5 ensures detection stability, ultimately achieving high-precision control of motor speed and torque, balancing power output and control accuracy.

[0061] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Although the present utility model has been disclosed above with reference to a preferred embodiment, it is not intended to limit the present utility model. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present utility model. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present utility model without departing from the scope of the present utility model shall still fall within the scope of the present utility model.

Claims

1. An external encoder type external brushless motor, characterized in that: The device includes an encoder shaft (1) fixed to an external structure, a stator unit (2) mounted on the encoder shaft (1), an encoder assembly (3), a bearing assembly, and a rotor unit (4). The rotor unit (4) is rotatably mounted on the encoder shaft (1) via the bearing assembly. The stator unit (2) is located in the inner cavity of the rotor unit (4). The stator unit (2) drives the rotor unit (4) to rotate. The rotor unit (4) is provided with an encoding detection structure. The encoder assembly (3) is non-contactly engaged with the encoding detection structure to detect the rotational position information of the rotor unit (4). Along the axial direction of the encoder shaft (1), the encoder assembly (3) is located in the inner cavity of the rotor unit (4) or on one side of the rotor unit (4). The encoder assembly (3) includes an encoder bracket (5) mounted on the encoder shaft (1) and an external encoder (6) mounted on the encoder bracket (5). The encoder bracket (5) is hollow inside and mounted on the encoder shaft (1). The external encoder (6) is one of a magnetic encoder, an inductive encoder, an optical encoder, and a Hall encoder.

2. The external encoder type external brushless motor according to claim 1, characterized in that: When the external encoder (6) is a photosensitive encoder, the encoding detection structure is a reflective code disk or a transparent grid that works with the photosensitive encoder; when the external encoder (6) is a magnetic encoder or a Hall encoder, the encoding detection structure is a magnetic ring or an inductive magnet that works with it; when the external encoder (6) is an inductive encoder, the encoding bracket (5) is a stator PCB, and the encoding detection structure is a rotor PCB that works with the stator PCB and the inductive encoder.

3. The external encoder type external brushless motor according to claim 1, characterized in that: The rotor unit (4) includes an end cover (7) sleeved on the bearing assembly, heat dissipation protrusions (8) disposed on the outer edge of the end cover (7), a rotating housing (9), and multiple permanent magnets disposed on the inner wall of the rotating housing. The multiple permanent magnets are arranged around the stator unit (2). The heat dissipation protrusions (8) include multiple protrusions disposed on the outer edge of the end cover (7).

4. The external encoder type external brushless motor according to claim 3, characterized in that: The bearing assembly includes two parallel support bearings (18), the stator unit (2) is located between the two support bearings (18), and the end cover (7) includes a rotating part (11) sleeved on the two support bearings (18); the rotating part (11) has an inner ring and an outer ring, and a fan blade structure is provided between the inner ring and the outer ring, and the permanent magnet is provided on the outer ring.

5. The external encoder type external brushless motor according to claim 4, characterized in that: The wind turbine structure has multiple arc-shaped centrifugal blades (12), which are arranged around the central axis of the coding shaft (1).

6. The external encoder type external brushless motor according to claim 4, characterized in that: One of the rotating parts (11) has its inner ring protruding into a pulley (13) axially away from the stator unit (2) along the encoder shaft (1). The end of the encoder shaft (1) away from the other rotating part (11) is provided with a key (14). The encoder assembly (3) is fixed to the key (14) and is located adjacent to the other rotating part (11).

7. The external encoder type external brushless motor according to claim 3, characterized in that: The multiple permanent magnets are arranged in a ring around the central axis of the encoding shaft (1).

8. The external encoder type external brushless motor according to claim 1, characterized in that: The encoder bracket (5) is provided with a shaped hole (16) adapted to the encoder shaft (1) and a receiving cavity (15) for accommodating the external encoder (6). The opening of the receiving cavity (15) faces the encoder detection structure of the rotor unit (4). The shaped hole (16) and the central axis of the functional receiving cavity (15) are coaxially arranged.

9. The external encoder type external brushless motor according to claim 1, characterized in that: Both ends of the encoding shaft (1) are provided with bushings (17), and the bushings (17) are fixed to the encoding shaft (1) by shaft keys and / or pins.

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