An electric machine

Abstract

The application provides a motor, in particular to the technical field of micro motor, which comprises a shell, a stator assembly fixed to the shell, a rotor assembly comprising a rotating shaft, the rotating shaft comprising a rotating shaft end close to the shell end, the rotating shaft being rotatably installed on the shell through a bearing, a magnet installed on the rotating shaft end through a sleeve joint structure, the sleeve joint structure comprising a first sleeve joint part and a second sleeve joint part connected with each other, the magnet being sleeved in the first sleeve joint part, and the rotating shaft end being sleeved in the second sleeve joint part, and a circuit board assembly fixed to the shell end, the circuit board assembly comprising a magnetic encoder corresponding to the magnet. The sleeve joint structure is arranged to connect the magnet and the rotating shaft, a middle hole structure for positioning is not needed, the space magnetic field intensity distribution after magnetization is met, and the angle position feedback precision of the motor is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of micro motor, and in particular to a motor. BACKGROUND

[0002] As a key executive component, micro motor has a wide range of applications in many fields such as automobiles, household appliances, communications, computers, robots, aerospace industry, industrial machinery, industrial control, military, etc. With the increasing global awareness of environmental protection and energy saving, improving motor efficiency has become a common goal of industry development. At present, in the field of micro motor, hollow cup motor, brushless DC motor, servo motor and other types are favored due to their high power density. These motors not only meet the development concept of green environmental protection and low carbon, but also show great potential in those application scenarios with high power consumption and high use frequency.

[0003] With the increasing demand for device performance in industries such as industrial robots and household appliances, i.e. pursuing higher energy efficiency, smaller size and stronger intelligence, the demand for motor lightweight, miniaturization and fast response capability is increasing. Therefore, the development of new types of motors such as hollow cup motor, servo motor, slotless brushless motor is constantly progressing towards high efficiency, lightweight and cost optimization. This trend is expected to become the mainstream direction of future motor industry development. In particular, PCB (Printed Circuit Board) axial flux motor, as a kind of micro motor with high torque density characteristics, is particularly suitable for application scenarios that require large torque in a small space, such as flexible hand motor and joint motor in the robot field, power system of small unmanned aerial vehicles, and micro motor in high-end medical equipment. Compared with traditional brushless motors and hollow cup motors, PCB axial flux motors can provide 2 to 3 times the power / torque density while ensuring better product consistency and lower development costs, improving production yield and process feasibility.

[0004] However, there is a significant problem in the existing design scheme of PCB axial flux motor: the method of opening a hole in the center of the magnet and directly assembling with the rotating shaft will cause signal loss phenomenon when the magnetic encoder detects the magnetic field signal generated in the rotation process of the motor rotor, thereby affecting the accuracy of angle feedback and failing to meet the demand of high performance application. This problem limits the further promotion and use of PCB axial flux motor in some high-precision applications. CONTENT OF THE INVENTION

[0005] In order to solve at least one of the above-mentioned problems of the prior art, the present application provides a motor, comprising:

[0006] The shell comprises a shell end portion.

[0007] A stator assembly is fixed to the housing;

[0008] A rotor assembly includes a rotor shaft having a rotor shaft end proximate to the housing end, the rotor shaft being rotatably mounted to the housing by a bearing;

[0009] A magnet is mounted to the rotor shaft end by a sleeve structure, the sleeve structure including a first sleeve portion and a second sleeve portion connected to each other, the magnet being sleeved in the first sleeve portion, and the rotor shaft end being sleeved in the second sleeve portion;

[0010] A circuit board assembly is fixed to the housing end, the circuit board assembly including a magnetic encoder corresponding to the magnet.

[0011] Optionally, the bearing includes an inner ring and an outer ring nested to each other, the inner ring being rotatably connected to the outer ring, the outer ring being fixed to the housing, and the rotor shaft being sleeved in the inner ring; the inner ring includes an inner ring end proximate to the housing end, the second sleeve portion includes a sleeve end distal to the housing end, and the inner ring end is in abutment with the sleeve end.

[0012] Optionally, an axial length of the rotor shaft end sleeved in the second sleeve portion is less than an axial length of the second sleeve portion.

[0013] Optionally, an axial length of the first sleeve portion matches an axial length of the magnet.

[0014] Optionally, the bearing and the sleeve structure are sleeved in a bearing sleeve, the bearing sleeve being fixed to the housing, and a gap being left between the bearing sleeve and the sleeve structure.

[0015] Optionally, the bearing sleeve is axially concentric with the sleeve structure, and an equal gap is left between the bearing sleeve and the sleeve structure.

[0016] Optionally, the bearing sleeve is axially concentric with the bearing, and an interference fit is provided between the bearing sleeve and the bearing.

[0017] Optionally, the first sleeve portion and the second sleeve portion are axially concentric, so that the magnet and the rotor shaft are axially concentric.

[0018] Optionally, the magnetic encoder and the magnet are axially concentric.

[0019] Optionally, an interference fit is provided between the first sleeve portion and the magnet, and an interference fit is provided between the second sleeve portion and the rotor shaft end.

[0020] With the above technical solutions, the present application has the following advantages:

[0021] The application provides an electric machine, comprising a shell, a stator assembly, a rotor assembly, a magnet and a circuit board assembly; wherein the shell comprises a shell end portion, the stator assembly is fixed in the shell; the rotor assembly comprises a rotating shaft, the rotating shaft comprises a rotating shaft end portion close to the shell end portion, the rotating shaft is rotatably installed on the shell through a bearing; the magnet is installed on the rotating shaft end portion through a sleeving structure, the sleeving structure is composed of a first sleeving portion and a second sleeving portion connected with each other, the magnet is sleeved in the first sleeving portion, and the rotating shaft end portion is sleeved in the second sleeving portion; the circuit board assembly is fixed on the shell end portion and comprises a magnetic encoder corresponding to the magnet. The magnet and the rotating shaft are connected through the sleeving structure, thereby avoiding the method of opening a hole in the magnet to realize positioning in the prior art, which seriously interferes with the spatial magnetic field distribution of the magnet after magnetization; the design of the sleeving structure ensures that the spatial magnetic field intensity distribution of the magnet after magnetization is not affected, thereby improving the angle position feedback precision of the electric machine, and the application scenario is particularly suitable for the application scenario with strict requirements on the angle precision. The sleeving structure also provides additional protection for the magnet in rotation, prevents displacement or falling of the magnet due to centrifugal force during high-speed operation, and enhances the safety and reliability of the system.

[0022] Other features and advantages of the application will be described in detail in the following specific embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description only show some embodiments of the application, and the same reference numerals generally represent the same components, and other drawings can be obtained by those skilled in the art without any creative effort.

[0024] Figure 1 is a structural schematic view of an electric machine provided by the embodiment of the application;

[0025] Figure 2 is a structural schematic view of the electric machine provided by the embodiment of the application. Figure 1 is a structural schematic view of A in the embodiment of the application.

[0026] The following is a supplementary description of the drawings:

[0027] 1, shell; 2, stator assembly; 3, rotating shaft; 4, bearing; 5, magnet; 6, sleeving structure; 7, first sleeving portion; 8, second sleeving portion; 9, circuit board assembly; 10, bearing sleeve. DETAILED DESCRIPTION

[0028] With reference to the drawings of the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0029] The term "one embodiment" or "an embodiment" as used herein means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one implementation of the application. In the description of the application, it should be understood that the terms "upper", "lower", "top", "bottom", etc. indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the application. In addition, the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features referred to. Therefore, the features defined with "first", "second" can be explicitly or implicitly included one or more of the features. Moreover, the terms "first", "second" and the like are used to distinguish similar objects, and do not necessarily describe a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the application described herein can be implemented in an order other than that illustrated or described herein.

[0030] Reference Figures 1-2 The present application provides an electric machine, which comprises:

[0031] The housing 1 comprises a housing end. The housing is used to protect the internal components from the external environment, while ensuring the stability and durability of the entire electric machine structure, and is usually made of high-strength metal materials to ensure its reliability and durability under various working conditions. The housing end is the end of the housing 1 close to the non-driving end of the electric machine.

[0032] Stator assembly 2, fixed to the housing 1. The stator assembly 2 includes the stator core and the stator winding, the main function of the stator winding is to generate a rotating magnetic field, through the on-off and change of current, drive the rotor to rotate, the main function of the stator core is to provide a closed magnetic circuit to enhance the concentration and strength of the magnetic field, so as to improve the efficiency and performance of the motor. The stator core is usually composed of multiple layers of silicon steel sheets, which can reduce eddy current loss and improve magnetic permeability, and the stator winding is wound by copper wire, which will generate a magnetic field when current flows, interacting with the magnetic field generated by the rotor to push the rotor to rotate. For PCB axial flux motor, the stator winding is copper wire wound on the PCB board, the design of the stator winding needs to accurately control the position and number of turns of the coil to ensure good insulation and magnetic field efficiency, and through the pressing process, it can ensure that the prepreg is fully filled into the copper coil, thereby ensuring good insulation.

[0033] Rotor assembly, including the shaft 3, the shaft 3 includes the shaft end near the housing end, the shaft 3 is rotatably mounted on the housing 1 through the bearing 4. The rotor assembly also includes the rotor core, the magnet 5, the balance block. Among them, the rotor core provides a closed magnetic circuit, enhances the concentration and strength of the magnetic field, supports the magnet 5 and ensures its stability during rotation; common materials include silicon steel sheets, iron-nickel alloys and other soft magnetic materials, which have high magnetic permeability and low magnetic hysteresis loss, and can effectively conduct magnetic field; the rotor core is usually disc-shaped or polygonal disc-shaped, matching the axial layout of the motor; the rotor core can be composed of multiple layers of thin sheet materials, with an insulating layer between each layer to reduce eddy current loss. The shaft 3 connects the rotor core and the load, transmits mechanical energy and ensures the stability of the rotor core during rotation, and the shaft 3 is usually cylindrical. The bearing 4 supports the shaft 3 to allow it to rotate freely, reduces friction and improves the efficiency and life of the motor; common types of bearings 4 include ball bearings and roller bearings, usually made of steel or ceramic materials, with high wear resistance and low friction coefficient. The balance block ensures the balance of the rotor during rotation, reduces vibration and noise, and is usually made of metal materials, with mass distribution adjusted as needed. The balance block can be installed on the edge or inside of the rotor core to achieve the best balance effect.

[0034] Magnet 5 is installed on the shaft end of the rotating shaft 3 through a sleeve structure 6; the sleeve structure 6 includes a first sleeve part 7 and a second sleeve part 8 connected together, the magnet 5 is sleeved in the first sleeve part 7, and the shaft end is sleeved in the second sleeve part 8. The magnet 5 is a key component in the rotor assembly, providing a constant magnetic field that interacts with the magnetic field generated by the stator winding to produce a driving force; common permanent magnet materials include neodymium iron boron (NdFeB), samarium cobalt (SmCo), etc.; the magnet 5 can be arc-shaped, square or rectangular, which varies according to different motor designs; the magnet 5 is usually arranged radially or tangentially with the rotor core, the radial arrangement of the magnet 5 has a magnetic field direction perpendicular to the surface of the rotor core, and the tangential arrangement of the magnet 5 has a magnetic field direction along the tangent direction of the surface of the rotor core. The radial dimension of the first sleeve part 7 matches the radial dimension of the magnet 5, ensuring the stable installation of the magnet 5, and the radial dimension of the second sleeve part 8 matches the radial dimension of the shaft end, ensuring the stable installation of the shaft end. In specific implementation, according to the working environment and performance requirements of the motor, the most suitable magnet material is selected and magnetized to achieve the required spatial magnetic field intensity distribution.

[0035] Circuit board assembly 9 is fixed to the end of the housing, and the circuit board assembly 9 includes a magnetic encoder corresponding to the magnet 5. The magnetic encoder is used to monitor the position and speed of the rotor in real time, providing accurate feedback signals to enable precise control of the motor. The circuit board assembly 9 also includes signal processing circuits, power management modules, communication interfaces and other components. The signal processing circuit is responsible for converting the magnetic field changes detected by the magnetic encoder into electrical signals, which can accurately reflect the angular position of the rotor after processing. The power management module ensures that the circuit board assembly can obtain stable power supply under various working conditions. The communication interface is used for data exchange with the external control system to realize remote monitoring and adjustment. Through the coordinated work of these components, the circuit board assembly 9 not only improves the control accuracy of the motor, but also enhances the reliability and flexibility of the system. When the magnet 5 rotates with the rotating shaft 3, the magnetic field intensity signal received by the magnetic encoder is more sinusoidal, and the magnetic field intensity amplitude is within the receiving range of the magnetic encoder, thereby ensuring the accuracy of the feedback of the motor rotor angular position; when the magnet 5 rotates one revolution with the rotating shaft 3, the magnetic encoder arranged according to the requirements can sense the sinusoidal magnetic field intensity waveform signal, and through magnetic-electric signal conversion, the position signal of the rotor can be accurately obtained. The quality of the rotor angular position feedback signal is closely related to the amplitude of the magnetic field intensity received by the magnetic encoder and the sinusoidal waveform, if the change of the magnetic field intensity amplitude is small and always within the receiving range of the magnetic encoder, and the better the sinusoidal waveform, the higher the accuracy of the rotor angular position.

[0036] In particular, in the embodiments of the present application, the motor not only realizes compactness and high efficiency in structure, but also achieves high precision and high reliability in performance. The design of the sleeve joint structure 6 not only ensures the stable installation of the magnet 5, but also avoids the problem of uneven magnetic field distribution caused by the hole in the magnet 5, thereby improving the angular position feedback precision of the motor, solving the problems of magnet installation and magnetic field distribution in traditional motors, and making the motor perform well in high-precision applications. In addition, the sleeve joint structure 6 can also provide additional protection for the rotating magnet 5, preventing it from being displaced or falling off due to centrifugal force during high-speed operation, thereby enhancing the safety and reliability of the system. Under the requirement of product miniaturization, improving the angular position feedback precision of the miniature axial flux motor (or other miniature motors with the same structure) has feasibility for motor product assembly applications with high angular precision requirements.

[0037] In one possible implementation, the bearing 4 includes a nested inner ring and outer ring, and the inner ring is rotationally connected with the outer ring. In a specific implementation, the inner ring and the outer ring can be rotationally connected through rolling elements such as balls or rollers. The outer ring is fixed to the housing 1 to ensure that it remains stationary during motor operation, and the shaft 3 is sleeved in the inner ring to allow the shaft 3 to rotate freely. The material of the bearing 4 is usually high-strength steel to withstand high loads and high-temperature environments during long-term operation. The inner ring includes an inner ring end portion near the housing end portion, and the second sleeve joint portion 8 includes a sleeve joint end portion away from the housing end portion, and the inner ring end portion is attached to the sleeve joint end portion, reducing the axial size chain and allowing the rotor angular feedback precision to be more accurate. The axial size chain refers to the cumulative error of all axial dimensions from one end of the motor to the other end. These errors can come from the slight deviations in the fitting and installation process of multiple components. By attaching the inner ring end portion to the sleeve joint end portion, the cumulative error in the axial size chain can be effectively reduced, ensuring that the axial position of the shaft 3 is more stable when rotating, thereby improving the precision of the magnetic field signal received by the magnetic encoder.

[0038] In particular, in the embodiments of the present application, by attaching the inner ring end portion to the sleeve joint end portion, the cumulative error in the axial size chain is effectively reduced, improving the precision of the rotor angular feedback, not only ensuring the efficient operation of the motor, but also enhancing the reliability and stability of the system, especially in high-precision applications, the advantages are particularly obvious, making the motor can maintain high performance and high reliability in various complex environments.

[0039] In one possible implementation, the axial length of the shaft end portion that is sleeved in the second sleeve portion 8 is less than the axial length of the second sleeve portion 8, so that there is a gap between the shaft end portion and the magnet 5. Specifically, during the operation of the motor, the shaft 3 may have slight axial movement due to factors such as vibration and thermal expansion. If the shaft end portion directly contacts the magnet 5, these slight axial movements may cause the accumulation of mechanical stress, affecting the stability and service life of the magnet 5. By leaving a gap between the shaft end portion and the magnet 5, these slight axial movements can be effectively absorbed, reducing the transmission of mechanical stress and ensuring the stability and reliability of the magnet 5. The magnetic field distribution generated by the magnet 5 is crucial to its performance. If the shaft end portion directly contacts the magnet 5, it may adversely affect the uniformity of the magnetic field, causing distortion of the magnetic field signal received by the magnetic encoder. By leaving a gap between the shaft end portion and the magnet 5, local distortion of the magnetic field can be reduced, making the magnetic field distribution more uniform and ensuring that the signal received by the magnetic encoder has good sinusoidal characteristics, closer to the ideal sinusoidal waveform. This uniform magnetic field distribution helps the magnetic encoder more accurately detect the position of the rotor, reduces distortion of the magnetic field signal, and thus improves positioning accuracy. If the shaft end portion directly contacts the magnet 5, long-term high-speed rotation may cause wear between the two, affecting the performance and life of the motor. By leaving a gap between the shaft end portion and the magnet 5, direct contact between the two can be reduced, reducing the risk of wear and extending the service life of the motor. Direct contact between the shaft end portion and the magnet 5 may introduce additional mechanical vibration and noise, which will affect the detection accuracy of the magnetic encoder. By leaving a gap between the shaft end portion and the magnet 5, these disturbances can be reduced, ensuring that the signal received by the magnetic encoder is purer and improving the accuracy of position detection.

[0040] Specifically, in the embodiments of the present application, by leaving a gap between the shaft end portion and the magnet 5, not only the mechanical stress and wear are reduced, but also the uniformity of the magnetic field distribution and the sinusoidal characteristics of the signal are ensured, and the additional mechanical vibration and noise disturbances are reduced, thereby improving the positioning accuracy of the rotor angle feedback. While improving the performance of the motor, the reliability and stability of the system are also enhanced, which is particularly suitable for application scenarios with high requirements for positioning accuracy.

[0041] In one possible implementation, the axial length of the first sleeve part 7 matches the axial length of the magnet 5, ensuring that the magnet 5 can be fully embedded in the first sleeve part 7 during installation, avoiding possible misalignment or looseness during installation, so that the magnet 5 can remain stable during high-speed rotation and will not be displaced due to vibration or impact, thereby improving the mechanical stability and operational reliability of the motor. Precise installation and stable fixation ensure that the magnet 5 can maintain good performance during long-term operation, prolonging the service life of the motor. Ensuring uniform distribution of the magnet 5 along the entire axial length, this uniform magnetic field distribution helps the magnetic encoder to receive more stable and accurate magnetic field signals, closer to the ideal sinusoidal waveform, thereby improving the accuracy of the position signal and the feedback accuracy of the rotor angular position, which in turn helps the motor control system to more accurately control the position and speed of the rotor, improving the control performance and response speed of the motor. If the axial length of the first sleeve part 7 does not match the axial length of the magnet 5, it may cause installation errors, affecting the installation position and stability of the magnet 5, and the axial length matching can ensure that the installation position of the magnet 5 of each motor is consistent, thereby improving the quality and consistency of the product. Precise axial length matching can simplify the manufacturing process and reduce rework and scrap rates caused by installation errors.

[0042] Specifically, in the embodiments of the present application, by matching the axial length of the first sleeve part 7 with the axial length of the magnet 5, not only is the precise installation and stable fixation of the magnet 5 achieved, but also the uniformity of the magnetic field distribution and the sinusoidal nature of the signal are ensured, thereby improving the feedback accuracy of the rotor angular position. While improving the performance of the motor, the reliability and stability of the system are also enhanced, making it particularly suitable for applications that require high positioning accuracy and long-term performance.

[0043] In one possible implementation, the bearing 4 and the sleeve structure 6 are sleeved in the bearing sleeve 10, the bearing sleeve 10 is fixed to the housing 1, and a gap is left between the bearing sleeve 10 and the sleeve structure 6. Specifically, the bearing sleeve 10 is arranged between the outer ring of the bearing 4 and the stator assembly 2, serving as an isolation and support, and a gap is left between the bearing sleeve 10 and the sleeve structure 6, so that the stator assembly 2 remains stationary while the rotor assembly rotates without interfering with each other, ensuring that the outer ring of the bearing 4, the bearing sleeve 10, and the stator assembly 2 remain stationary during motor operation, while the inner ring of the bearing 4, the shaft 3, the magnet 5, and the sleeve structure 6 rotate freely. In specific implementations, the material of the bearing sleeve 10 is usually high-strength steel to withstand high loads and high-temperature environments during long-term operation. During operation of the motor, components may expand due to temperature changes, and the gap needs to be set to compensate for thermal expansion to ensure the normal operation of the components at different temperatures and avoid jamming or damage due to thermal expansion. The gap can absorb and reduce the vibration generated during motor operation, reducing the transmission of vibration to other components, thereby improving the smoothness of motor operation and noise control.

[0044] Specifically, in the embodiments of the present application, the bearing 4 and the sleeve structure 6 are sleeved in the bearing sleeve 10, and a gap is left between the bearing sleeve 10 and the sleeve structure 6, which ensures that the rotation of the rotor assembly does not interfere with the static state of the stator assembly, and improves the reliability and performance of the motor.

[0045] In one possible implementation, the bearing sleeve 10 and the sleeve structure 6 are axially concentric, that is, the bearing sleeve 10 and the sleeve structure 6 maintain the same center line in the axial direction of the motor, and the center axes of the two coincide without offset. In specific implementation, high-precision machine tools and measuring tools are usually used for machining and detection to ensure the coaxiality of the inner and outer surfaces of the bearing sleeve 10 and the sleeve structure 6. During installation, special clamps and alignment tools are used to ensure the accurate alignment of the bearing sleeve 10 and the sleeve structure 6 in the axial direction. The axial concentric design reduces the unbalanced force caused by eccentricity, avoids unnecessary vibration and noise of the rotor during high-speed rotation, ensures the stable axial position of the rotor during operation, and improves the smoothness and reliability of the motor. Reducing eccentricity and vibration can reduce the wear of the bearing and the rotor, and prolong the service life of the motor.

[0046] The gap between the bearing sleeve 10 and the sleeve structure 6 is uniform in all directions, which ensures that the bearing sleeve 10 and the sleeve structure 6 do not interfere with each other, and avoids mechanical stress and wear caused by inconsistent gaps. During operation of the motor, components may expand due to temperature changes, and the uniform gap design can compensate for thermal expansion, ensuring the normal operation of components at different temperatures and avoiding jamming or damage caused by thermal expansion. The uniform gap can absorb and reduce the vibration generated during motor operation, reducing vibration transmission to other components, thereby improving the smoothness and noise control of the motor.

[0047] Specifically, in the embodiments of the present application, the bearing sleeve 10 and the sleeve structure 6 are axially concentric, and a uniform gap is left between the bearing sleeve 10 and the sleeve structure 6, which ensures the accurate alignment and non-interference of the components during installation and operation, and improves the reliability and performance of the motor.

[0048] In one possible implementation, the bearing sleeve 10 is axially concentric with the bearing 4, that is, the bearing sleeve 10 and the bearing 4 maintain the same center line in the motor axial direction, and the center axes of the two coincide without offset. The unbalanced force caused by eccentricity is reduced, unnecessary vibration and noise of the rotor during high-speed rotation are avoided, the stable axial position of the rotor during operation is ensured, the running stability and reliability of the motor are improved, and the eccentricity and vibration are reduced to reduce the wear of the bearing and the rotor and prolong the service life of the motor. In specific implementation, high-precision machine tools and measuring tools are usually used for machining and detection to ensure the coaxiality of the inner and outer surfaces of the bearing sleeve 10 and the bearing 4. During installation, special clamps and alignment tools are used to ensure the accurate alignment of the bearing sleeve 10 and the bearing 4 in the axial direction.

[0049] The bearing sleeve 10 and the bearing 4 are in interference fit. Specifically, by making the inner diameter of the bearing sleeve 10 slightly smaller than the outer diameter of the bearing 4, a certain interference amount is generated to realize close connection. The interference fit ensures the close connection between the bearing sleeve 10 and the bearing 4, improves the strength and stability of the connection, effectively prevents the bearing 4 from loosening during operation due to vibration or impact, ensures the long-term stable operation of the motor, reduces the gap between the bearing sleeve 10 and the bearing 4, improves the sealing performance, prevents dust and pollutants from entering, and prolongs the service life of the bearing. During installation, the bearing 4 is usually pressed into the bearing sleeve 10 by using a hot mounting method or a press mounting method. The hot mounting method is to heat the bearing 4 to expand it, and then quickly mount it into the cooled bearing sleeve 10; the press mounting method is to press the bearing 4 into the bearing sleeve 10 by using hydraulic or mechanical pressure.

[0050] Specifically, in the embodiment of the present application, by making the bearing sleeve 10 axially concentric with the bearing 4 and adopting interference fit, the accurate alignment and stable connection of the components during installation and operation are ensured, mechanical interference and wear are reduced, the mechanical stability of the components is improved, the service life of the motor is prolonged, the design of reducing eccentricity and vibration improves the running stability of the motor, reduces noise, and improves the reliability and performance of the motor.

[0051] In one possible implementation, the first sleeve part 7 is axially concentric with the second sleeve part 8, so that the magnet 5 is axially concentric with the rotor shaft 3, i.e. the magnet 5 and the rotor shaft 3 maintain the same center line in the axial direction of the motor, and the center axes of the magnet 5 and the rotor shaft 3 coincide without offset. This reduces the unbalanced force caused by eccentricity and avoids unnecessary vibration and noise of the magnet 5 during high-speed rotation; ensures that the magnet 5 maintains a stable axial position during operation, improves the smoothness and reliability of the motor operation; reducing eccentricity and vibration can reduce the wear of the magnet 5 and the rotor shaft 3 and prolong the service life of the motor. In specific implementation, high-precision machine tools and measuring tools are usually used for machining and detection to ensure the coaxiality of the inner and outer surfaces of the first sleeve part 7 and the second sleeve part 8. During installation, special fixtures and alignment tools are used to ensure that the first sleeve part 7 and the second sleeve part 8 are accurately aligned in the axial direction.

[0052] Specifically, in the embodiments of the present application, the first sleeve part 7 is axially concentric with the second sleeve part 8, which ensures that the magnet 5 is axially concentric with the rotor shaft 3, ensures the uniformity of the magnetic field distribution and the sinusoidal nature of the signal, thereby improving the feedback accuracy of the rotor angle position, and is particularly suitable for application scenarios with high requirements for positioning accuracy and long-term performance.

[0053] In one possible implementation, the magnetic encoder is axially concentric with the magnet 5, i.e. the magnetic encoder and the magnet 5 maintain the same center line in the axial direction of the motor, and the center axes of the two coincide without offset. This reduces the distortion of the magnetic field signal caused by eccentricity and avoids unnecessary errors when the magnetic encoder detects the magnetic field; ensures that the magnetic encoder maintains a stable axial position during operation, improves the stability and reliability of the detection signal. Specifically, the magnetic encoder is fixed on the circuit board assembly 9, the circuit board assembly 9 is fixed on the end of the housing, and the position of the magnetic encoder is aligned with the magnet 5 to ensure the accuracy of the detection signal; the magnetic encoder detects the magnetic field signal generated by the magnet 5 to monitor the position and speed of the rotor in real time, and the axial concentricity of the magnetic encoder and the magnet 5 ensures the uniform distribution of the magnetic field signal and reduces signal distortion; uniform magnetic field distribution makes the signal received by the magnetic encoder closer to the ideal sinusoidal waveform, improving the accuracy of the position signal.

[0054] Specifically, in the embodiments of the present application, the magnetic encoder is axially concentric with the magnet 5, which ensures the accuracy and consistency of the magnetic encoder when detecting the magnetic field signal generated by the magnet 5, ensures the uniformity of the magnetic field distribution and the sinusoidal nature of the signal, thereby improving the feedback accuracy of the rotor angle position and improving the positioning accuracy and performance of the motor. It is particularly suitable for application scenarios with high requirements for positioning accuracy and long-term performance.

[0055] In one possible implementation, the first sleeve part 7 is in interference fit with the magnet 5, and the second sleeve part 8 is in interference fit with the shaft end. Specifically, the inner diameter of the first sleeve part 7 is slightly smaller than the outer diameter of the magnet 5, and a certain interference amount is generated to achieve a tight connection; the tight connection between the first sleeve part 7 and the magnet 5 is ensured, the strength and stability of the connection are improved, the magnet 5 is effectively prevented from loosening due to vibration or impact during operation, the long-term stable operation of the motor is ensured, the gap between the first sleeve part 7 and the magnet 5 is reduced, the sealing performance is improved, dust and pollutants are prevented from entering, and the service life of the magnet 5 is prolonged. During installation, the magnet 5 is usually pressed into the first sleeve part 7 by using a hot mounting method or a press mounting method. The hot mounting method is to expand the magnet 5 by heating, and then quickly mount it into the cooled first sleeve part 7; the press mounting method is to press the magnet 5 into the first sleeve part 7 by using hydraulic or mechanical pressure. Specifically, the inner diameter of the second sleeve part 8 is slightly smaller than the outer diameter of the shaft end, and a certain interference amount is generated to achieve a tight connection; the tight connection between the second sleeve part 8 and the shaft end is ensured, the strength and stability of the connection are improved, the shaft end is effectively prevented from loosening due to vibration or impact during operation, the long-term stable operation of the motor is ensured, the gap between the second sleeve part 8 and the shaft end is reduced, the sealing performance is improved, dust and pollutants are prevented from entering, and the service life of the shaft is prolonged. During installation, the shaft end is usually pressed into the second sleeve part 8 by using a hot mounting method or a press mounting method; the hot mounting method is to expand the shaft end by heating, and then quickly mount it into the cooled second sleeve part 8; the press mounting method is to press the shaft end into the second sleeve part 8 by using hydraulic or mechanical pressure.

[0056] Specifically, in the embodiment of the present application, interference fit is adopted between the first sleeve part 7 and the magnet 5 and between the second sleeve part 8 and the shaft end, the tight connection and stability of each component during installation and operation are ensured, the reliability and performance of the motor are improved, the long-term stable operation of the motor is ensured, and it is particularly suitable for application scenarios with high requirements for long-term performance.

[0057] In summary, the motor of the present application comprises a shell, a stator assembly, a rotor assembly, a magnet and a circuit board assembly; wherein the shell comprises a shell end portion, the stator assembly is fixed in the shell; the rotor assembly comprises a rotating shaft, the rotating shaft comprises a rotating shaft end portion close to the shell end portion, the rotating shaft is rotatably installed on the shell through a bearing; the magnet is installed on the rotating shaft end portion through a sleeve joint structure, the sleeve joint structure is composed of a first sleeve joint portion and a second sleeve joint portion connected together, the magnet is sleeved in the first sleeve joint portion, and the rotating shaft end portion is sleeved in the second sleeve joint portion; the circuit board assembly is fixed on the shell end portion and comprises a magnetic encoder corresponding to the magnet. The sleeve joint structure is adopted to connect the magnet and the rotating shaft, avoiding the method of opening a hole in the magnet to realize positioning in the prior art, which seriously interferes with the spatial magnetic field distribution of the magnet after magnetization; the design of the sleeve joint structure ensures that the spatial magnetic field intensity distribution of the magnet after magnetization is not affected, thereby improving the angular position feedback accuracy of the motor, and the sleeve joint structure is particularly suitable for application scenarios with strict requirements on angular accuracy. The sleeve joint structure also provides additional protection for the rotating magnet, preventing displacement or falling of the magnet due to centrifugal force during high-speed operation, thereby enhancing the safety and reliability of the system.

[0058] In the present application, unless otherwise explicitly specified and limited, the terms "connected", "connected", and the like should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the connection or interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0059] It should be noted that: the above sequence of the embodiments of the present application is only for description, not representing the advantages and disadvantages of the embodiments, and the above description of the present application is for specific embodiments, other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims can be executed in different orders in different embodiments and can achieve the expected results. In addition, the processes depicted in the drawings do not necessarily require a specific order or connection order to achieve the desired results, and in some embodiments, multiple tasks can be processed in parallel or it can be advantageous.

[0060] Each embodiment in the present specification is described in a progressive manner, and the same or similar parts between each embodiment can be referred to each other, and each embodiment focuses on the differences from other embodiments.

[0061] The above is only the preferred embodiment of the present application, and does not limit the present application, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An electric machine characterized in that, The application relates to a motor, comprising: a housing (1) comprising a housing end; a stator assembly (2) fixed to the housing (1); a rotor assembly comprising a rotor shaft (3) comprising a rotor shaft end close to the housing end, the rotor shaft (3) being rotatably mounted to the housing (1) via a bearing (4); a magnet (5) mounted to the rotor shaft end of the rotor shaft (3) via a sleeve structure (6), the sleeve structure (6) comprising a first sleeve part (7) and a second sleeve part (8) connected to each other, the magnet (5) being sleeved in the first sleeve part (7), and the rotor shaft end being sleeved in the second sleeve part (8); a circuit board assembly (9) fixed to the housing end, the circuit board assembly (9) comprising a magnetic encoder corresponding to the magnet (5).

2. The electric machine of claim 1, wherein, The bearing (4) comprises an inner ring and an outer ring nested with each other, the inner ring is rotatably connected to the outer ring, the outer ring is fixed to the housing (1), and the rotor shaft (3) is sleeved in the inner ring; the inner ring comprises an inner ring end close to the housing end, and the second sleeve part (8) comprises a sleeve end away from the housing end, and the inner ring end is attached to the sleeve end.

3. The electric machine of claim 2, wherein, An axial length of the rotor shaft end sleeved in the second sleeve part (8) is smaller than an axial length of the second sleeve part (8).

4. The electric machine of claim 3, wherein, An axial length of the first sleeve part (7) matches an axial length of the magnet (5).

5. The electric machine of claim 1, wherein, The bearing (4) and the sleeve structure (6) are sleeved in a bearing sleeve (10), the bearing sleeve (10) is fixed to the housing (1), and a gap is left between the bearing sleeve (10) and the sleeve structure (6).

6. The electric machine of claim 5, wherein, The bearing sleeve (10) is axially concentric with the sleeve structure (6), and the bearing sleeve (10) and the sleeve structure (6) have an equal gap therebetween.

7. The electric machine of claim 6, wherein, The bearing sleeve (10) is axially concentric with the bearing (4), and the bearing sleeve (10) and the bearing (4) are in interference fit.

8. The electric machine of claim 1, wherein, The first sleeve part (7) and the second sleeve part (8) are axially concentric, so that the magnet (5) and the rotor shaft (3) are axially concentric.

9. The electric machine of claim 8, wherein, The magnetic encoder is axially concentric with the magnet (5).

10. The electric machine of claim 8, wherein, The first sleeve part (7) and the magnet (5) are in interference fit, and the second sleeve part (8) and the rotor shaft end are in interference fit.

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