653 results about "Magnetic line" patented technology

The invention discloses a sound production device, a sound production module and electronic equipment, and relates to the technical field of electroacoustic transduction, a vibration plate of a vibration system of the sound production device comprises a first plate part and a second plate part which are located on different horizontal planes, the top of a voice coil is connected with the first plate part, and the second plate part is located on the inner side of the voice coil; a center magnetic part of the magnetic circuit system comprises a first center magnet and a second center magnet which are located on the two opposite sides of the second plate part, the first center magnet is close to the top of the voice coil, and the second center magnet is close to the bottom of the voice coil. The first center magnet and the second center magnet are magnetized in the first direction and are opposite in magnetizing direction, and the magnetic energy product of the first center magnet is larger than that of the second center magnet. According to the sound production device, the thinning design can be realized, the BL value is effectively improved, the magnetic lines are distributed more uniformly, the BLx curve is flatter, and thus the distortion is reduced.

The invention discloses a sound production device, a sound production module and electronic equipment, and relates to the technical field of electroacoustic transduction, a vibration plate of a vibration system of the sound production device comprises a first plate part, a second plate part and a third plate part which are integrally arranged, the first plate part and the second plate part are located on different horizontal planes, the top of a voice coil is connected with the first plate part, and the top of the voice coil is connected with the third plate part. The third plate part is connected with the inner circumferential wall of the voice coil in an attached mode, the two ends, in the first direction, of the third plate part are connected with the first plate part and the second plate part respectively, and a center magnetic part of the magnetic circuit system comprises a first center magnet and a second center magnet which are located on the two opposite sides of the second plate part. The sides, facing the vibrating diaphragm assembly, of the first center magnet and the second center magnet are both exposed in the inner cavity of the sound production device, and the first center magnet and the second center magnet are magnetized in the first direction and are opposite in magnetizing direction. According to the sound production device, the thinning design can be realized, the BL value is effectively improved, the magnetic lines are distributed more uniformly, the BLx curve is flatter, and thus the distortion is reduced.

The invention discloses a sound production device, a sound production module and electronic equipment, and relates to the technical field of electroacoustic transduction, a vibration plate of a vibration system of the sound production device comprises a first plate part and a second plate part which are located on different horizontal planes, the top of a voice coil is connected with the first plate part, and the second plate part is located on the inner side of the voice coil; a central magnetic part of the magnetic circuit system comprises a first central magnet and a second central magnet which are located on the two opposite sides of the second plate part, the first central magnet and the second central magnet are magnetized in the first direction, and the magnetizing directions of the first central magnet and the second central magnet are opposite. The side, opposite to the vibrating diaphragm assembly, of the first center magnet is connected with the first magnet yoke, the side, opposite to the vibrating diaphragm assembly, of the second center magnet and the edge magnetic part are connected with the second magnet yoke, and the peripheral edges of the first magnet yoke and the second magnet yoke are connected in a welded mode. According to the sound production device, the thinning design can be realized, the BL value is effectively improved, the magnetic lines are distributed more uniformly, the BLx curve is flatter, and thus the distortion is reduced.

The invention relates to the technical field of transformers, and particularly discloses a small-size and strong-short-circuit-current-resistant transformer, which comprises a transformer body, the transformer body comprises an iron core, a plurality of iron cores, a plurality of short-circuit-current-resistant coils, a plurality of short-circuit-current-resistant coils and a plurality of short-circuit-current-resistant coils, the insulating cylinder is arranged on the outer side of the core column in a sleeving manner; the winding sleeves the outer side of the insulating cylinder, the winding comprises a circular coil wound on the outer wall of the insulating cylinder and a plurality of layers of elliptical coils wound on the outer side of the circular coil, and the trend of the elliptical coils is parallel to magnetic lines generated by the circular coil; heat dissipation channels parallel to the axis of the core column are formed between the circular coils and the oval coils and between every two adjacent oval coils. The space of the core column can be effectively utilized, the elliptical ring can fill the external space, the magnetic field trend of the outer elliptical coil is parallel to that of the inner circular coil, high-frequency loss caused by the proximity effect and eddy-current loss during short circuit can be effectively reduced, and the normal operation efficiency and short-circuit endurance capacity of the transformer are improved.

The invention relates to the technical field of light sources, particularly discloses a method and a device for adjusting the central position of a plasma, and aims to realize accurate positioning and stable control of the plasma by accurately controlling output parameters of a magnetic field generator. According to the method, a magnetic field generator with a specific shape and distribution is utilized, a magnetic field with a closed magnetic line structure is generated in a plasma chamber, charged particles in plasma are guided to move along a preset path, and it can be ensured that the plasma reaches and is kept at an expected position by monitoring and adjusting magnetic field parameters in real time.

The invention discloses a design method of a star simulator three-dimensional divertor target plate, and belongs to the technical field of magnetic confinement fusion. The method comprises the following steps: firstly, deducing a circumferential thermal load uniformity theoretical model, then, calculating background information required by target plate generation, and finally, carrying out target plate generation by using the obtained background information and the circumferential thermal load uniformity theoretical model. The target plate is generated based on parameter control, the target plate capable of achieving uniform distribution of the circumferential thermal load is provided, the circumferential uniform distribution of the thermal load of the divertor target plate can be effectively improved, and the peak value of the thermal load of the divertor target plate can be effectively reduced. The target plate generated by the method conforms to standard output formats among different analog calculations. Data can be conveniently transmitted between integrated simulation platforms, and the working process is simplified. The divertor target plate is generated on the basis of the basic physical assumption that the magnetic lines of the magnetic field and the heat flow are attenuated along the radial position, and the method is suitable for all star simulator devices with three-dimensional magnetic island structures and has universal applicability.

The utility model discloses a magnetic leveling device of a pendulum bob type laser demarcation device, which comprises a hanging bracket and a pendulum body hung in the hanging bracket, a magnetic damping body consisting of a plurality of magnets is arranged on the hanging bracket according to a Halbach array, and a magnetic field which is made of non-magnetic conductive materials and can cut magnetic lines in a magnetic field generated by the magnetic damping body is arranged on the pendulum body. The utility model aims to provide a damping piece which adopts two different forms of Halbach arrays to generate magnetic damping, and compared with the existing common magnet arrangement scheme, the magnetic flux is obviously enhanced, so that a stronger magnetic damping effect is generated, and the magnetic damping effect is improved. The magnetic leveling device can effectively prevent the swinging body from swinging excessively, so that the leveling time is effectively shortened, the leveling speed and precision of the laser demarcation device are further improved, and the working efficiency is remarkably improved.

The invention relates to the technical field of motors, in particular to a motor stator core. The motor stator core comprises a plurality of punching sheets, a plurality of pear-shaped grooves extending along the radial direction are uniformly distributed on the inner circumference of each punching sheet, and two adjacent surfaces of each pear-shaped groove are in fillet transition, so that magnetic field concentration of sharp edges is eliminated, and the problem of overhigh local magnetic flux density is reduced; the arc-shaped structure of the pear-shaped groove can provide a smoother magnetic path, magnetic resistance is reduced, magnetic lines are distributed more reasonably, magnetic hysteresis loss is reduced, and a magnetic circuit is improved. All the punching sheets are stacked in the axial direction, the pear-shaped grooves in all the punching sheets are in one-to-one correspondence to form a plurality of inclined notches, and compared with original vertical notches of the stator iron core, the inclined notches of the stator iron core have the advantages that the space for accommodating windings is increased, and the magnetic field density is improved. And the inclined notches enable the stator teeth and the rotor teeth to be not completely aligned, so that the tooth harmonic phases are different and mutually offset, thereby weakening the overall harmonic, reducing the electromagnetic noise and vibration, and further improving the motor performance.

The utility model discloses a Hall signal output device for a mouse wheel. Comprising an encoder fixing support arranged in the mouse, an encoder roller rotationally arranged in the encoder fixing support, a magnetic ring arranged in the encoder roller, and a Hall encoder which is arranged on the side edge of the encoder fixing support and right faces the magnetic ring. When the encoder roller rotates, the magnetic ring is driven to rotate, so that the direction of the magnetic line of force of the magnetic ring is changed, and the Hall encoder generates pulse signal output after identifying the change of the magnetic line of force of the magnetic ring. The Hall signal output device for the mouse wheel is simple in structure, low in production cost, high in precision and high in response speed, and meets the use requirements of modern people.

The present invention provides an oil pipeline cleaning robot, belonging to the technical field of oil pipeline cleaning. It includes a propulsion mechanism, at one end of which there is a steering column and a support column. The propulsion mechanism is movably connected to the support column through the steering column, and magnetic lines are arranged on the support column. It also includes a cleaning and resetting component connected to the support column, which is used for resetting and reducing the volume when the propulsion mechanism cleans inside the oil pipeline. The cleaning and resetting component includes a second push ring and a pair of first push rings. The second push ring is located between the pair of first push rings. The pair of first push rings are used to push out the sediments on the inner wall of the oil pipeline, and the second push ring is used to clean the sediments on the inner wall of the oil pipeline. By setting the cleaning and resetting component, the present invention can gradually clean the inner wall of the oil pipeline; during the contraction process of the support component, the support plate is driven to fold, which can reduce the volume of the cleaning and resetting component, and solves the problem that the cleaning robot in the prior art has a fixed structure and is difficult to take out once it gets stuck.

The invention belongs to the technical field of motor control, and particularly relates to a motor three-phase counter electromotive force phase sequence detection circuit and a running direction judgment device. The phase sequence detection circuit comprises a comparison circuit and further comprises a tachogenerator coaxially connected with the motor to be detected, and the output end of the tachogenerator is electrically connected with the input end of the comparison circuit so that the phase sequence of the three-phase counter electromotive force of the motor to be detected can be obtained through the three-phase voltage output by the tachogenerator through the comparison circuit. The three-phase counter electromotive force of the to-be-tested motor is directly detected through the tachogenerator coaxially connected with the to-be-tested motor. The rotor of the tachogenerator rotates along with the rotation of the motor to be tested, and the rotor of the tachogenerator cuts magnetic lines in the operation process, thereby generating the three-phase counter electromotive force of the motor to be tested. The technical problem that in the prior art, when ground voltage detection is not accurate due to external interference, detected counter electromotive force is not accurate, and then the motor control effect is affected is solved.

A magnetic field propulsion unit generates a drive force when being arranged in an external magnetic field. The magnetic field propulsion unit includes a support structure, a magnetic field generating device attached to the support structure and configured to generate a first magnetic field, an energy supply unit, and a control unit. The energy supply unit provides the magnetic field generating device with electrical energy. The control unit controls the energy supply unit so that the energy supply unit supplies energy to the magnetic field generating device. The control unit supplies varying current to the magnetic field generating device. The magnetic field generating device has a central axis and is arranged in the external magnetic field such that the central axis is inclined with respect to magnetic field lines of the external magnetic field at an angle different from 0°, 90°, 180°, and 270°.

The invention discloses a sound production device, a sound production module and electronic equipment, and relates to the technical field of electroacoustic transduction. A vibration plate of a vibration system of the sound production device comprises a first plate part and a second plate part which are arranged in a split mode and located on different horizontal planes; the waterproof film comprises a first connecting part located at the top of the voice coil, a second connecting part in attached connection with the inner circumferential wall of the voice coil and a third connecting part located in the voice coil, the first plate part is connected with the first connecting part, and the second plate part is connected with the third connecting part; a center magnetic part of the magnetic circuit system comprises a first center magnet and a second center magnet which are located on the two opposite sides of a second plate part, the first center magnet and the second center magnet are magnetized in the first direction, and the magnetizing directions are opposite. According to the sound production device, the thinning design can be realized, the BL value is effectively improved, the magnetic lines are distributed more uniformly, the BLx curve is flatter, and thus the distortion is reduced.

To provide a magnetic therapeutic device capable of suppressing alignment disorder of a magnetic line.SOLUTION: A magnetic bracelet 10 as a band-shaped magnetic therapeutic device in which multiple magnet pieces 11, 12 are connected in a rosary shape in multiple columns includes a first magnet piece 11 having a large magnetic line strength and a second magnet piece 12 having a small magnetic line strength. One or two second magnetic pieces 12 are arranged between the first magnetic pieces 11 in a rosary shape connection direction of each column, and the first magnetic piece 11 and the second magnetic piece 12 are adjacent to each other among the respective columns of the band shape in a lateral width direction.SELECTED DRAWING: Figure 2B

The invention belongs to the field of oil and gas exploitation, geothermal exploitation and deep ground engineering, and discloses an oil and gas shaft crack plugging pressure repair material and method based on microwave heating bismuth-based alloy, the material comprises 74%-86% of bismuth-based alloy powder, 10%-15% of Fe3O4-SiO2 core-shell magnetic particles, 3%-8% of a microwave sensitizer and 1%-3% of a wetting agent. The repairing material is conveyed to the position, where shaft crack plugging repairing needs to be conducted, in the oil and gas shaft, then the repairing material is melted in a microwave heating mode, then the melted alloy is filled in shaft crack plugging, and then a rotating gradient magnetic field is used for repairing the oil and gas shaft crack. And the liquid alloy is driven to directionally migrate to a target crack area along the magnetic line, and after alloy liquid is cooled and solidified, pressure repairing of the oil and gas shaft crack plugging target position is achieved. Precise positioning, efficient filling, phase change control and complete recovery of the repairing material can be achieved in the extremely deep environment, and therefore the high-quality repairing requirement for oil and gas shaft crack plugging pressure repairing achieved through efficient liquefaction of plugging metal can be met.

The invention discloses a vacuum arc extinguish chamber structure with large rated current and strong breaking capacity, which comprises a structure body, and is characterized in that the structure body comprises a static contact assembly, the static contact assembly comprises a static end arc contact and a static end main contact, and the static end arc contact is arranged in front of the static end main contact and protrudes for a preset distance d along the on-off direction; and the moving contact assembly comprises a moving end main contact and a moving end arc contact, and the moving end main contact and the moving end arc contact are located on the same plane. According to the invention, the effect that the main contact does not burn arc during breaking is realized, the contact surface of the main contact is protected from being ablated by the arc, and a physical foundation is laid for the high capacity of the vacuum arc-extinguishing chamber. The moving end arc contact is provided with a coil structure so as to generate a transverse magnetic field or a longitudinal magnetic field, and the magnetic lines of force between the static end arc contact and the moving end arc contact have the combined action of the longitudinal magnetic field and the transverse magnetic field, so that the breaking capacity is high.

The invention relates to an arc-shaped continuous casting space-time electromagnetic stirring device and method.The electromagnetic stirring device comprises a foot roller, a secondary cooling area, a solidification tail end and a plurality of electromagnetic stirring assemblies; the electromagnetic stirring assembly comprises a coil, an axial magnet yoke and a radial magnet yoke; the axial magnet yoke is fixedly mounted on the back of the radial magnet yoke, so that the electromagnetic stirring assemblies mounted in the secondary cooling area are connected in series; alternating current is applied to each coil, induced magnetic lines of force flow through the radial magnet yokes and the axial magnet yokes, a superimposed magnetic field moving in the radial direction and the axial direction is generated, the superimposed magnetic field interacts with the induced current to form spirally upward electromagnetic force, and molten metal is driven to move spirally. A flow field and a temperature field in a casting blank are improved, a stirring area is enlarged, and center porosity, shrinkage cavities and segregation are reduced. Compared with the prior art, the device has the advantages of integration of multiple functions, enlargement of a stirring area, flexible and adjustable parameters, defect control, high universality and the like.

The invention provides a rotor punching sheet, a rotor iron core, a rotor, a motor and an air conditioner, the rotor punching sheet is provided with more than two magnetic pole forming areas corresponding to rotor magnetic poles, and each magnetic pole forming area is internally provided with a magnetic steel groove which is arranged on a q axis and extends along the radial direction; the rotor punching sheet is provided with a first magnetic barrier groove located on the d axis between every two adjacent magnetic steel grooves. Wherein first magnetic bridges are formed between the first magnetic barrier grooves and the adjacent magnetic steel grooves on the two sides, and the width of each first magnetic bridge is gradually increased in the radial outward direction of the rotor punching sheet. According to the technical scheme of the invention, the magnetic lines of force can be gradually drawn close to the d axis from the two sides of the d axis, and the sinusoidal property of the magnetic flux in the air gap is better, so that the torque pulsation of the tangential motor can be reduced.

The utility model provides a novel self-power-generating wheel body structure with a shaft wheel rotating synchronously without differential speed, which relates to the technical field of power-generating wheels and comprises a fixed part and a rotatable part which are arranged in a coupling mode. The rotatable part comprises a wheel, and a connecting component is arranged in the rotatable part; the connecting component is provided with a mounting position for mounting a power part; the power part is driven by a power source to generate torque, and then the rotatable part is driven to rotate relative to the fixed part with an axis as the center. A magnetic ring and a generator core which are correspondingly used are arranged at the joint of the fixed part and the rotatable part; the rotatable part rotates relative to the fixed part, so that the generator core and the magnetic ring rotate relative to each other to cut magnetic lines of force to generate current. The self-generating wheel body has the beneficial effects that the blank of the self-generating wheel body in the existing market is filled, the self-generating wheel body can be applied to a wheel body which is represented by a child tricycle and is positioned on a front fork, and the wheel body is driven to rotate through pedal rotation so as to synchronously generate electricity or emit light.

The invention provides a linear vibration motor which comprises a shell, a rotor, a stator and an elastic part, the rotor and the stator are accommodated in the shell at an interval, the elastic part is used for elastically suspending the rotor in the shell, and the stator is fixed in the shell and used for driving the rotor to vibrate; the rotor comprises two groups of magnetic steels which are arranged in parallel at intervals; the stator comprises a coil which is arranged between the two groups of magnetic steel and is spaced from the two groups of magnetic steel in the first direction, the winding plane of the coil is parallel to the vibration direction of the rotor, and the two opposite ends of the coil in the second direction are fixed to the two opposite sides of the shell respectively; the first direction, the second direction and the vibration direction of the rotor are perpendicular to each other. According to the linear vibration motor, the magnetic lines of force can be completely closed through the design of the double magnetic steels, so that the driving efficiency of the stator for driving the rotor is improved.

A transport system 10C has a configuration to move a transport body 500 in conjunction with movement of a moving body 200 by using repulsion based on a magnetic force applied between moving body magnets 213 and a transport body magnet 523 when there is a proximal positional relation between these magnets. The transport system 10C includes a control coil 903 that controls a traveling state of the moving body 200, and a coil drive control unit that drives and controls the control coil. The control coil 903 is configured to apply a magnetic force to the moving body magnets 213. The coil drive control unit supplies the control coil 903 with power to cause the control coil 903 to attract the moving body magnets 213 against an air flow flowing within an air blowing tube 100 in order to control and prevent the moving body 200 from traveling.

The invention relates to a low-harmonic permanent magnet synchronous motor rotor punching sheet and a motor rotor, and relates to the technical field of permanent magnet synchronous motors. According to the scheme, the rotor punching sheet is provided with the first magnetic steel groove and the second magnetic steel groove which form a V shape and are symmetrical about the D axis of the motor rotor, and the opening of the V shape faces the outer circumferential wall of the rotor punching sheet body. According to the structure, the distribution of a motor rotor magnetic field is improved, the magnetic field is more uniform, the salient pole rate is higher, the weak magnetic speed expansion capability is stronger, the structural strength is better, the harmonic content is lower, and the sine property of the magnetic field can be improved. On the outer circumferential wall of the rotor punching sheet body, a first auxiliary groove is formed between the first magnetic isolation bridge and the second magnetic isolation bridge and close to the first magnetic isolation bridge, and a second auxiliary groove is formed between the second magnetic isolation bridge and the D shaft and close to the second magnetic isolation bridge. On the premise of ensuring the mechanical strength of the magnetic isolation bridge, the magnetic line direction is changed, the magnetic leakage is reduced, the air gap flux density waveform is improved, the harmonic content is reduced, and the torque ripple and electromagnetic noise are reduced.

The invention provides an oblique coil electromagnetic classificator for separating weak magnetic impurities from strong magnetic concentrate, which comprises a separation cylinder, an ore feeding device and a flushing device, an ore feeding pipe of the ore feeding device extends into the separation cylinder from the top end of the separation cylinder, the flushing device is arranged below the ore feeding pipe, and an oblique coil is arranged on the outer side of the separation cylinder, so that the weak magnetic impurities can be separated from the strong magnetic concentrate. Magnetic lines of force are obliquely distributed, magnetic linkages formed by magnetic particles are oblique, the whole magnetic linkages can be efficiently impacted in cooperation with vertical component force Fz of water flow of the flushing device, and scattering of magnetic aggregates is facilitated; the tail control flat coil and the concentrate gathering flat coil at the upper end and the lower end effectively control tailings and concentrates respectively, so that the separation efficiency of strong magnetic concentrates and weak magnetic impurities is improved, for example, in the iron-titanium separation operation of vanadium titano-magnetite ore dressing, ilmenite mixed into iron ore concentrates can be reduced, the grade of the iron ore concentrates can be improved, and titanium metal resources can be fully recycled.

The invention discloses an ultrasonic abrasive flow surface texture machining device and method based on an auxiliary magnetic field, and belongs to the field of precision machining and surface engineering. The ultrasonic abrasive flow surface texture machining device comprises a workbench, an ultrasonic vibration generating device, a magnetic field generating device, an abrasive flow machining system and a three-dimensional motion platform. The composite abrasive particle suspension is composed of a basic solution, carbonyl iron powder magnetic particles and silicon carbide abrasive particles. According to the method, magnetic particles are guided by a magnetic field to form a chain along magnetic lines of force, ultrasonic high-frequency impact is combined, abrasive materials are driven to impact the surface of a workpiece in order, a submicron texture with the consistent direction and the uniform size is formed, the depth ranges from 0.2 micrometer to 2 micrometers, and the width ranges from 1 micrometer to 20 micrometers. Texture parameters are flexibly regulated and controlled through magnetic field and ultrasonic parameters, and the method has the advantages of being high in machining precision, high in controllability, low in cost, environmentally friendly and recyclable, is suitable for precise parts of bearings and cutters, and can remarkably improve the tribological performance and wettability of the parts.

A plasma confinement device comprising an arrangement of electromagnetic coils on the faces of a polyhedron with alternating polarity. Each coil is connected to a coil of opposing polarity via a lobe comprising a loop of more electromagnetic coils. The lobe coils connect the field lines such that the entire configuration has only closed field lines. The coils of each lobe are graded in size, such that the field lines converge to their densest at the apex of the lobe. In the central region plasma is confined by magnetic mirror reflection from the converging field lines in the lobes and stabilised by the convexity of the field lines between coils. The device may form the basis of a magnetically confined thermonuclear fusion reactor.

A magnet includes a first sub-magnet and a second sub-magnet. A direction of a magnetic line inside the first sub-magnet and a direction of a magnetic line inside the second sub-magnet each are inclined toward a plane on which the magnet is located. More magnetic lines may be aggregated in space at one side of the magnet, and magnetic lines are sparse around the magnet.

The invention discloses a Helmholtz coil material lightning magnetic field shielding performance measuring device, which comprises a magnetic field generation device, a shielding test box is arranged in a magnetic field coverage range of the magnetic field generation device, an open hole is formed in the shielding test box, and the open hole enables a magnetic line of force of the magnetic field generation device to transversely penetrate through the shielding test box. The shielding test box is internally provided with the signal measurement unit, the signal measurement unit measures the magnetic field in the shielding test box, the lightning stroke magnetic field environment is accurately simulated, and the repeatability and accuracy of the shielding performance test are improved. The invention further discloses a method for measuring the lightning magnetic field shielding performance of the Helmholtz coil material, the lightning magnetic field shielding performance of the measured shielding material is measured by applying the device for measuring the lightning magnetic field shielding performance of the Helmholtz coil material, and the problem that traditional measurement is poor in accuracy is effectively solved.

This disclosure provides an X-ray imaging device and a wireless power transmission device with electromagnetic shielding. The wireless power transmission device includes: a first annular structure, on which a first frame is fixed, and a first winding is wound; a second annular structure, on which a second frame is fixed, and a second winding is wound; wherein the second annular structure is rotatable relative to the first annular structure; and a metal shielding assembly disposed relative to the first winding and / or the second winding, the metal shielding assembly being used to generate a reverse magnetic field based on the eddy current effect to weaken the main magnetic flux of the wireless power transmission device. This disclosure utilizes the reverse magnetic field generated by the metal shielding assembly based on the eddy current effect to weaken the main magnetic flux of the wireless power transmission device, thereby reducing magnetic field leakage and thus reducing electromagnetic interference of the wireless power transmission device.

Magnetic coil (1) comprising a coil body (2) with a winding chamber (20) and an excitation winding (3) accommodated in the winding chamber (20), characterized in that the excitation winding (3) is wound in several layers from a square wire (30).

The utility model relates to the technical field of motors, in particular to a novel brushless direct current motor, which comprises a rotor assembly (100), a stator assembly (200), a first end cover (300) and a second end cover (400), the rotor assembly (100) comprises a rotor (101), a rotor shaft sleeve (102) and rotor magnetic steel (103), and the rotor shaft sleeve (102) is made of aluminum materials; the second end cover (400) is provided with a Hall plate (500), and the Hall plate (500) is provided with three surface-mounted Hall elements (501) used for sensing the rotor magnetic steel (103). Due to the adoption of the structural design, the rotor shaft sleeve of the rotor assembly is made of an aluminum material, so that the distribution of magnetic lines of air gaps in the motor is changed, and the problems of large cogging torque and noise of the motor are effectively solved; a Hall element on the Hall plate directly induces motor rotor magnetic steel in a patch mode, so that the reliability of the motor is greatly improved, the structure is simplified, and assembly is facilitated.