阅读说明：本技术 一种具有分数槽的直流无刷外转子电机 (Direct-current brushless outer rotor motor with fractional slots ) 是由 左宜 计佰强 于 2021-08-02 设计创作，主要内容包括：本发明公开了一种具有分数槽的直流无刷外转子电机,其特征是,包括定子、转子、转轴,所述转子设置在定子内部与定子同轴设置,所述定子由定子齿、定子槽和缠绕在定子齿上的绕组组成,转子铁芯外周面表贴有若干钕铁硼永磁磁钢,所述若干钕铁硼永磁磁钢呈海尔贝克阵列分布。转子铁芯表贴表钕铁硼永磁磁钢,并且钕铁硼永磁磁钢采用海尔贝克阵列排布,有效提高电机功率密度和永磁体利用率。钕铁硼永磁磁钢每极槽数为不可约的真分数,减小虚拟单元电机数目,从而达到降低电机脉动的效果。钕铁硼永磁磁钢外表面设有碳纤维磁钢固定层,对高速运转中的磁钢离心力有冲抵作用,提高电机稳定性和使用寿命。(The invention discloses a direct-current brushless outer rotor motor with fractional slots, which is characterized by comprising a stator, a rotor and a rotating shaft, wherein the rotor is arranged inside the stator and is coaxial with the stator, the stator consists of stator teeth, stator slots and windings wound on the stator teeth, a plurality of neodymium iron boron permanent magnet steels are pasted on the outer peripheral surface of a rotor iron core, and the neodymium iron boron permanent magnet steels are distributed in a Halbach array. The surface of the rotor core is pasted with the surface neodymium iron boron permanent magnet steel, and the neodymium iron boron permanent magnet steel is arranged in a Halbach array, so that the power density of the motor and the utilization rate of the permanent magnet are effectively improved. The number of each pole slot of the neodymium iron boron permanent magnet steel is irreducible, so that the number of virtual unit motors is reduced, and the effect of reducing motor pulsation is achieved. The outer surface of the neodymium iron boron permanent magnet steel is provided with a carbon fiber steel fixing layer which has an impact effect on the centrifugal force of the steel magnet in high-speed operation, so that the stability of the motor is improved and the service life of the motor is prolonged.)

1. The direct-current brushless outer rotor motor with the fractional slots is characterized by comprising a motor stator and a motor rotor coaxially arranged outside the motor stator, wherein the stator consists of stator teeth, stator slots and windings wound on the stator teeth, a plurality of magnet steel slots are uniformly distributed on the inner peripheral surface of the outer rotor, magnetic poles of the outer rotor consist of a plurality of neodymium iron boron permanent magnet steel embedded in the magnet steel slots respectively, and the plurality of neodymium iron boron permanent magnet steel are distributed in a Halbach array.

2. The dc brushless external rotor motor with fractional slot of claim 1, wherein said ndfeb permanent magnets are arranged with equal angular spacing, the included angle between two adjacent ndfeb permanent magnets is equal, and the included angle between two adjacent ndfeb permanent magnets is not more than 45 °.

3. The DC brushless external rotor motor with fractional slot of claim 2, wherein the number of slots per pole of Nd-Fe-B permanent magnet steel satisfies q = z/2pm, q is a fraction that cannot be completely divided,

wherein m is the number of phases, 2p is the number of poles, and z is the total number of stator slots.

4. The brushless DC external rotor motor according to claim 3, wherein the magnetic steel slots have a sector ring-shaped cross section, the outer side of the sector ring is a cambered surface, the inner side of the sector ring is a plane, symmetrical chamfers are arranged at two corners of the inner side of the magnetic steel slots, a Y-shaped magnetic isolation slot is arranged between two adjacent magnetic steel slots, and the open end of the magnetic isolation slot faces the outer peripheral surface of the stator.

5. The DC brushless external rotor motor according to claim 4, wherein the radial width of the NdFeB permanent magnet steel is greater than the circumferential width, and the cross section of the NdFeB permanent magnet steel is the same as the cross section of the magnetic steel slot.

6. The direct-current brushless external rotor motor with fractional slots according to claims 1-5, wherein a first hollow-out window is arranged on an end surface of the inner ring of the magnetic steel slot, and a second hollow-out window is arranged on an opposite end surface of two adjacent magnetic steel slots.

Technical Field

The invention relates to the field of motor magnetic circuits, in particular to a direct-current brushless inner rotor motor with a Halbach array.

Background

The motors used by the existing small household appliances of the washing machine are generally a DD motor and a BLDC motor which are direct-current brushless motors, and the driving principle of the BLDC motor is that a belt is used for connecting the motor and a load device, namely, a small wheel drives a large wheel. However, the belt transmission can cause the problems of large energy loss and low motor efficiency caused by the existence of reverse clearance, inertia, friction and insufficient rigidity in the rotation of the motor; the DD motor is a development direction of advanced level in the industry, rigid connection is directly adopted between the DD motor and a driven workpiece, intermediate links such as a screw rod, a gear, a speed reducer and the like are not needed, and the problems of reverse clearance, inertia, friction and insufficient rigidity existing in a transmission system are avoided to the greatest extent. However, the DD motor needs to change the installation mode of the traditional manufacturing enterprises such as washing machines due to the structural change, the cost is high, and the DD motor has no gear ratio of a belt, and has the problems of low acceleration, difficult high speed ratio, namely low motor power density and large torque pulsation.

For example, a "make things convenient for direct drive motor of speed governing" that discloses on chinese patent literature, its bulletin number "CN 212323852U" includes, including directly driving motor body, the right side of directly driving motor body top and bottom all is equipped with the dead lever, the right side of directly driving motor body is equipped with the cover, the top and the bottom of cover all are equipped with the card case, the right side of dead lever is located the inner box of card case, the inner chamber of card case is equipped with the movable plate, the spout with the movable plate looks adaptation is all seted up to the both sides of card incasement chamber, the both sides at movable plate top and the junction of card case all are equipped with the spring, the top of movable plate is equipped with the pull rod, the top of pull rod runs through and extends to the top of card case, the top of pull rod is equipped with the pull ring. But above-mentioned scheme comes the staff of being convenient for to maintain the motor through the structure of installing convenient to detach at motor top and bottom, does not promote the power performance of motor in essence, and direct drive motor still has the acceleration low, high-speed difficulty, and motor power density is difficult to break through, and the big problem that leads to motor vibration and noise of torque ripple.

Disclosure of Invention

The invention provides a direct-current brushless outer rotor motor with fractional slots, aiming at solving the problems that the power density of the motor of a direct-drive brushless motor in the prior art is difficult to break through, the acceleration of the motor is difficult to be increased at a low speed, and the vibration and noise of the motor are difficult to be reduced.

In order to achieve the purpose, the invention adopts the following technical scheme: the utility model provides a brushless external rotor electric machine of direct current with fraction groove, includes motor stator and the motor rotor of coaxial setting in the motor stator outside, the stator comprises stator tooth, stator groove and the winding of winding on the stator tooth, external rotor inner peripheral surface evenly distributed has a plurality of magnet steel grooves, the external rotor magnetic pole comprises a plurality of neodymium iron boron permanent magnet steel of embedding a plurality of magnet steel grooves respectively, a plurality of neodymium iron boron permanent magnet steel are halbach array distribution. The output waveform tends to a perfect sine wave, the influence of harmonic magnetic potential is greatly weakened, and the power density and the permanent magnet utilization rate of the permanent magnet synchronous wind driven generator are effectively improved.

Preferably, the neodymium iron boron permanent magnet steels are arranged at equal angular intervals, the magnetization included angles between every two adjacent neodymium iron boron permanent magnets are equal, and the magnetization included angle between every two adjacent neodymium iron boron permanent magnet steels is not more than 45 degrees. The Halbach magnetic steel array further improves the excitation magnetic field to increase the torque density of the motor and improve the performance of the motor.

Preferably, the number of each pole slot of the neodymium iron boron permanent magnet steel satisfies q = z/2pm, q is a fraction which cannot be completely divided,

wherein m is the number of phases, 2p is the number of poles, and z is the total number of stator slots. The fractional slot is adopted to effectively weaken the higher harmonic potential generated by the non-sinusoidal distribution of the magnetic field of the magnetic pole, improve the waveform of electromotive force, reduce the pulse vibration amplitude of each magnetic flux caused by the change of the magnetic conductance of the air gap, and reduce the pulse vibration loss on the surface of the magnetic pole.

Preferably, the cross section of each magnetic steel groove is in a fan-shaped ring shape, the outer side face of the fan-shaped ring is an arc face, the inner side face of the fan-shaped ring is a plane, symmetrical chamfers are arranged at two end corners of the inner side face of each magnetic steel groove, a Y-shaped magnetism isolating groove is arranged between every two adjacent magnetic steel grooves, and the opening end of each magnetism isolating groove faces the outer peripheral face of the stator. The magnetism isolating groove reduces the magnetic line of force passing through the interpolar magnetism isolating position of two adjacent permanent magnets to form a passage when charging magnetism, and improves the magnetic density waveform.

Preferably, the radial width of the neodymium iron boron permanent magnet steel is larger than the width in the circumferential direction, and the cross section of the neodymium iron boron permanent magnet steel is the same as the cross section of the magnetic steel groove in shape. The cross-section of neodymium iron boron permanent magnet steel is fan-shaped, the outer side surface of the fan-shaped is a cambered surface, the inner side surface of the fan-shaped is a plane, symmetrical chamfers are arranged at two end angles of the inner side surface of the magnetic steel groove, the inner side surface of the neodymium iron boron permanent magnet steel and the inner side surface of the magnetic steel groove form a salient pole structure, and the torque of the motor is effectively improved.

Preferably, the end face of the inner ring of the magnetic steel groove is provided with a first hollow window, and the end faces of two adjacent magnetic steel grooves opposite to each other are provided with second hollow windows. The mechanical reliability of the magnetic steel is enhanced, the magnetic circuit loss is reduced, and the motor efficiency is further improved.

Therefore, the invention has the following beneficial effects: (1) the invention applies the Halbach array to the outer rotor motor, and effectively improves the power density of the motor and the utilization rate of the permanent magnet. (2) The number of each pole slot of the neodymium iron boron permanent magnet steel is irreducible, so that the number of virtual unit motors is reduced, and the effect of reducing motor pulsation is achieved. (3) The magnetic steel is fixed in the embedded magnetic steel groove, and the hollow window is arranged on the magnetic steel groove, so that the mechanical reliability of the magnetic steel is enhanced, the magnetic circuit loss is reduced, and the motor efficiency is further improved.

Drawings

Fig. 1 is a schematic structural diagram of an embodiment of the present invention.

Fig. 2 is a schematic cross-sectional structure of an embodiment of the present invention.

In the figure: 1. rotor 2, magnet steel groove 3, stator 4, stator slot 5, neodymium iron boron permanent magnet steel 6, stator tooth 7, chamfer 8, magnetism-isolating groove 9, first fretwork window 10, second fretwork window.

Detailed Description

The invention is further described with reference to the following detailed description and accompanying drawings.

Example (b):

referring to FIGS. 1-2, a DC brushless external rotor motor with fractional slots is disclosed,

the motor comprises a motor stator and a motor rotor 1 coaxially arranged outside the motor stator, wherein the stator is composed of stator teeth 6, stator slots 4 and windings wound on the stator teeth 6, a plurality of magnetic steel slots 2 are uniformly distributed on the inner peripheral surface of the outer rotor 1, the cross sections of the magnetic steel slots 2 are in a fan-shaped ring shape, the outer side surface of the fan-shaped ring shape is an arc surface, the inner side surface of the fan-shaped ring shape is a plane, symmetrical chamfers 7 are arranged at two end angles of the inner side surface of each magnetic steel slot 2, a Y-shaped magnetism isolating slot 8 is arranged between every two adjacent magnetic steel slots 2, and the opening end of each magnetism isolating slot 8 faces the outer peripheral surface of the stator. The magnetism isolating groove 8 reduces the magnetic force lines to form a passage through the magnetism isolating position between the poles of two adjacent permanent magnets during magnetization, and improves the magnetic density waveform.

The magnetic pole of the outer rotor 1 is composed of a plurality of neodymium iron boron permanent magnet steel 5 respectively embedded into a plurality of magnet steel grooves 2, and the plurality of neodymium iron boron permanent magnet steel 5 are distributed in a Halbach array. The neodymium iron boron permanent magnet steels 5 are arranged at equal angular intervals, the magnetization included angles between every two adjacent neodymium iron boron permanent magnets are equal, and the magnetization included angle between every two adjacent neodymium iron boron permanent magnet steels 5 is not more than 45 degrees. The radial width of the neodymium iron boron permanent magnet steel 5 is larger than the width in the circumferential direction, and the cross section of the neodymium iron boron permanent magnet steel 5 is the same as the cross section of the magnet steel groove 2. The cross-section of neodymium iron boron permanent magnet steel 5 is fan-shaped, and fan-shaped lateral surface is the cambered surface, and fan-shaped medial surface is the plane, and 2 medial surface both ends angle departments of magnet steel groove are equipped with symmetrical chamfer 7, make 5 medial surfaces of neodymium iron boron permanent magnet steel and 2 medial surfaces of magnet steel groove form salient pole structure, effectively improve motor torque.

The end face of the inner ring of each magnetic steel groove 2 is provided with a first hollow window 9, and the end faces, opposite to the adjacent magnetic steel grooves 2, are provided with second hollow windows 10. The mechanical reliability of the magnetic steel is enhanced, the magnetic circuit loss is reduced, and the motor efficiency is further improved.

The specific embodiments described herein are merely illustrative of the spirit of the invention. Various modifications or additions may be made to the described embodiments or alternatives may be employed by those skilled in the art without departing from the spirit or ambit of the invention as defined in the appended claims.

Although the terms rotor, stator, magnetic steel slots, halbach array, flux barriers etc. are used more herein, the possibility of using other terms is not excluded. These terms are used merely to more conveniently describe and explain the nature of the present invention; they are to be construed as being without limitation to any additional limitations that may be imposed by the spirit of the present invention.