CN114977578A

CN114977578A - Motor, household appliance, garden tool and vehicle

Info

Publication number: CN114977578A
Application number: CN202110211920.8A
Authority: CN
Inventors: 刘旭初; 李涛; 高江明
Original assignee: Kingclean Electric Co Ltd; Jiangsu Kingclean Intelligent Appliance Co Ltd
Current assignee: Kingclean Electric Co Ltd; Jiangsu Kingclean Intelligent Appliance Co Ltd
Priority date: 2021-02-25
Filing date: 2021-02-25
Publication date: 2022-08-30
Anticipated expiration: 2041-02-25
Also published as: WO2022179315A1; CN114977578B

Abstract

The invention relates to a motor, a household appliance, a garden tool and a vehicle. The motor includes: the rotor comprises a rotor core, wherein the outer peripheral surface of the rotor core comprises a first cambered surface and a second cambered surface which are alternately distributed along the circumferential direction, a first equivalent cylindrical surface is formed by taking the center of the rotor core as a first axis, the first cambered surface is tangent to the first equivalent cylindrical surface, and the second cambered surface is offset towards the center of the rotor core relative to the first equivalent cylindrical surface; the stator core, the rotor core outside is located to the stator core cover, and the terminal portion that the pole shoe is close to rotor core includes first terminal surface, second terminal surface and the third terminal surface that connects gradually along circumference to first axis forms the equal-effect face of cylinder of a circle as the axis, and the second terminal surface is tangent with equal-effect face of cylinder of a circle of second, and first terminal surface and third terminal surface all squint towards the direction of keeping away from the center of rotor core for equal-effect face of a circle of second. The motor can be more stable in operation, and can reduce vibration, so that the generated vibration noise is smaller.

Description

Motor, household appliance, garden tool and vehicle

Technical Field

The invention relates to the technical field of motors, in particular to a motor, a household appliance, a garden tool and a vehicle.

Background

The permanent magnet brushless motor is a motor with a development prospect at present, and is widely applied to various fields of aerospace, national defense, industrial and agricultural production, household appliances and the like due to lower price and higher efficiency. Especially, the embedded permanent magnet brushless motor has high structural strength, large salient pole ratio, easy field weakening and speed expansion, and high field weakening operation efficiency, and is very suitable for application occasions of low-speed and high-speed alternate operation. However, many current permanent magnet brushless motors are not stable enough in the operation process, and the generated vibration noise is large.

Disclosure of Invention

Based on the above, the invention provides the motor which can run more stably, reduce vibration and generate less vibration noise.

An electric machine comprising:

the motor outputs power through the rotor shaft, the outer peripheral surface of the rotor core comprises a first arc surface and a second arc surface which are alternately distributed along the circumferential direction, a first equivalent cylindrical surface is formed by taking the center of the rotor core as a first axis, the first arc surface is tangent to the first equivalent cylindrical surface, and the second arc surface is offset towards the center of the rotor core relative to the first equivalent cylindrical surface;

the stator comprises a stator core, the stator core is sleeved outside the rotor core, the stator core comprises a stator tooth part, a pole shoe is formed at the end part, close to the rotor core, of the stator tooth part, the end part, close to the rotor core, of the pole shoe comprises a first end surface, a second end surface and a third end surface which are sequentially connected along the circumferential direction, a second equivalent cylindrical surface is formed by taking the first axis as the axis, the second end surface is tangent to the second equivalent cylindrical surface, and the first end surface and the third end surface are both deviated towards the direction far away from the center of the rotor core relative to the second equivalent cylindrical surface;

the shell is positioned outside the rotor and the stator, the stator is fixedly connected with the shell, and the rotor shaft is connected with the shell through a bearing.

In one embodiment, the diameter of the first equivalent cylindrical surface is D ₁ The diameter of the second equivalent cylindrical surface is D ₂ The mechanical air gap of the motor is delta, the offset distance of the second cambered surface relative to the first equivalent cylindrical surface is d, and the radius of the first cambered surface is R ₄ The radius of the second cambered surface is R ₅ ，D ₂ ＝D ₁ +2δ，0.1D ₁ ≤R ₄ ≤0.45D ₁ ，0.5D ₁ ≤R ₅ ≤0.9D ₁ ，0＜d≤2δ。

In one embodiment, d ═ δ, R ₄ ＝0.242D ₁ ，R ₅ ＝0.583D ₁ 。

In one embodiment, the second end face is a third arc face coinciding with the second equivalent cylindrical surface, and the first end face and the third end face are planes tangent to the second equivalent cylindrical surface.

In one embodiment, the first end surface and the third end surface are symmetrically distributed on two sides of the second end surface, and a distance X between an end of the first end surface along the circumferential direction and the second equivalent cylindrical surface ₁ In the range of 0 < X ₁ ≤0.6mm。

In one embodiment, the first end face, the second end face, and the third end face form a fourth arc, an axis of the fourth arc being offset from the first axis.

In one embodiment, the radius R of the fourth cambered surface ₆ In the range of 0 < R ₆ ＜0.825D ₂ The distance X between the end part of the fourth cambered surface along the circumferential direction and the second equivalent cylindrical surface ₂ In the range of 0 < X ₂ ≤0.6mm。

In one embodiment, a third equivalent cylindrical surface is formed by taking the first axis as an axis, a winding slot is formed between adjacent stator tooth portions, a slot bottom wall of the winding slot is a fifth arc surface, the fifth arc surface comprises a fifth arc surface first section, a fifth arc surface second section and a fifth arc surface third section which are sequentially connected along the circumferential direction, the fifth arc surface second section is tangent to the third equivalent cylindrical surface, and the fifth arc surface first section and the fifth arc surface third section are both offset towards the center of the rotor core relative to the third equivalent cylindrical surface.

In one embodiment, the diameter D of the third equivalent cylindrical surface ₃ In the range of 1.4D ₁ ＜D ₃ ＜1.65D ₁ Radius R of the fifth cambered surface ₇ In the range of D ₃ /8≤R ₇ ＜D ₃ /2。

In one embodiment, a plurality of sets of magnetic steel grooves distributed along the circumferential direction are formed in the rotor core, each magnetic steel groove comprises a first magnetic steel groove portion and a second magnetic steel groove portion, the first magnetic steel groove portion and the second magnetic steel groove portion are arranged at an angle, each rotor tooth portion is arranged between the first magnetic steel groove portion and the second magnetic steel groove portion, first magnetic steel is clamped in the first magnetic steel groove portion, and second magnetic steel is clamped in the second magnetic steel groove portion.

In one embodiment, the rotor core further includes a rotor yoke, the magnetic steel slot is located radially outside the rotor yoke, the rotor yoke is provided with a first pre-tightening member protruding towards the first magnetic steel slot and a second pre-tightening member protruding towards the second magnetic steel slot, the rotor core is provided with a boss protruding towards the first magnetic steel slot and the adjacent second magnetic steel slot along the radial outer end, two ends of the first magnetic steel are respectively abutted against the first pre-tightening member and the boss, and two ends of the second magnetic steel are respectively abutted against the second pre-tightening member and the boss.

In one embodiment, the boss protrudes from the side walls of the first magnetic steel groove and the second magnetic steel groove.

Household appliance, including above-mentioned motor.

Gardening tool, including foretell motor.

A vehicle comprising an electric machine as described above.

In the motor, on one hand, the peripheral surface of the rotor core of the rotor is provided with a first cambered surface and a second cambered surface which are alternately distributed, and the second cambered surface is inwards deviated towards the center of the rotor core; on the other hand, a pole shoe of a stator core of the stator is provided with a first end face, a second end face and a third end face which are sequentially connected along the circumferential direction, and the first end face and the third end face are deviated towards the direction which is far away from the center of the rotor core outwards. The rotor and the stator are matched through the structure, so that the cogging torque and the torque fluctuation of the motor can be reduced, the vibration of the motor is reduced, the motor runs more stably, and the vibration noise can be reduced.

The invention further provides a household appliance, and by applying the motor, the running is more stable, and the vibration noise is smaller.

The invention further provides a garden tool, and by applying the motor, the garden tool is more stable in operation and less in vibration noise.

The invention further provides a vehicle, and by applying the motor, the running is more stable, and the vibration noise is smaller.

Drawings

Fig. 1 is a schematic structural diagram of a rotor core and a stator core in the prior art;

fig. 2 is a schematic cross-sectional view of a rotor core and a stator core according to an embodiment of the present invention;

FIG. 3 is a schematic structural view of the rotor core of FIG. 2;

FIG. 4 is a schematic cross-sectional view of the rotor core of FIG. 2;

fig. 5 is a schematic structural view of the stator core of fig. 2;

FIG. 6 is a cross-sectional view of a stator core in accordance with an embodiment of the present invention;

FIG. 7 is an enlarged view of a portion of FIG. 6 at A;

fig. 8 is a schematic cross-sectional view of a stator core in another embodiment of the invention;

FIG. 9 is an enlarged view of a portion of FIG. 8 at B;

FIG. 10 is an enlarged view of a portion of FIG. 6 at C;

FIG. 11 is a cogging torque waveform diagram of the rotor core and stator core configuration of FIG. 1;

FIG. 12 is a cogging torque waveform diagram of the rotor core and stator core configuration of FIG. 2;

FIG. 13 is a load torque waveform of the rotor core and stator core structure shown in FIG. 1;

FIG. 14 is a load torque waveform of the rotor core and stator core structure shown in FIG. 2;

fig. 15 is a line back emf waveform for the rotor core and stator core configuration shown in fig. 1;

fig. 16 is a line back emf waveform for the rotor core and stator core configuration shown in fig. 2;

fig. 17 is a waveform diagram of a load line back emf of the rotor core and stator core structure shown in fig. 1;

fig. 18 is a waveform diagram of a load line back electromotive force of the rotor core and stator core structure shown in fig. 2.

Reference numerals:

the rotor comprises a rotor core 100, a rotor yoke 110, a first preload piece 111, a second preload piece 112, a rotor tooth 120, a first magnetic steel groove 131, a second magnetic steel groove 132, a boss 140, a first gap 151, a second gap 152, a first cambered surface 161, a second cambered surface 162 and a first equivalent cylindrical surface 170;

the stator comprises a stator core 200, a stator yoke 210, a stator tooth part 220, a pole shoe 230, a first end surface 231, a second end surface 232, a third end surface 233, a fourth cambered surface 234, a winding slot 240, a fifth cambered surface 241, a fifth cambered surface first section 2411, a fifth cambered surface second section 2412, a second equivalent cylindrical surface 250 and a third equivalent cylindrical surface 260;

first magnetic steel 310, second magnetic steel 320.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "transverse," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, but are not intended to indicate or imply that the device or element so referred to must have a particular orientation, be constructed and operated in a particular orientation, and are not to be construed as limiting the invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless explicitly specified otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the present invention, unless otherwise expressly stated or limited, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through an intermediate. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like as used herein are for illustrative purposes only and do not denote a unique embodiment.

An embodiment of the invention provides a motor, which comprises a rotor, a stator and a shell. Referring to fig. 2 to 4, the rotor includes a rotor core 100 and a rotor shaft, the rotor shaft is connected to the rotor core 100, the rotor shaft can rotate synchronously with the rotor core 100, and the motor outputs power through the rotor shaft to drive the working component to rotate. The outer circumferential surface of the rotor core 100 includes first arc surfaces 161 and second arc surfaces 162 that are alternately distributed along the circumferential direction and smoothly transited, and the central position of the rotor core 100 is set as a first axis O ₁ A first equivalent cylindrical surface 170 is formed, all the first arcs 161 are tangent to the first equivalent cylindrical surface 170, and the second arcs 162 are offset inwardly with respect to the first equivalent cylindrical surface 170. Inwardly offset herein means toward approaching the first axis line O ₁ Is offset.

Referring to fig. 2, 5 to 6, the stator includes a stator core 200, the stator core 200 is sleeved outside the rotor core 100, the stator core 200 includes a stator yoke portion 210 and a plurality of stator teeth 220, and the plurality of stator teeth 220 are distributed along a circumferential direction. The end of the stator tooth portion 220 close to the rotor core 100 is formed with a pole shoe 230, and the end of the pole shoe 230 includes a first end surface 231, a second end surface 232, and a third end surface 233 distributed along the circumferential direction. One end of the second end surface 232 is connected to the second end surface 231, and the other end is connected to the third end surface 233. About a first axis O ₁ As an axis, a second equivalent cylindrical surface 250 is formed, the second end surface 232 is tangent to the second equivalent cylindrical surface 250, and the first end surface 231 and the third end surface 233 are each offset outwardly relative to the second equivalent cylindrical surface 250. Herein outwardly offset refers to a direction away from the first axis O ₁ Is offset.

The outside of stator and rotor is located to the shell cover, and stator and shell fixed connection are connected through the bearing between rotor shaft and the shell to carry out along axial spacing to the rotor shaft.

In the above embodiment, the end face of the pole shoe 230 is equivalent to a material cut, and a part of the material is cut at the two ends of the pole shoe 230, so as to realize outward deviation. In rotor core 100, second arc surface 162 is also equivalent to a material cut, and it can be considered that first arc surface 161 is partially cut to obtain second arc surface 162, so that inward shift is achieved. It should be noted that the offset herein does not mean a parallel offset, but two ends of the second arc surface 162 are smoothly connected with a first arc surface 161, and the middle of the second arc surface 162 is inwardly collapsed. If the first air gap meets a preset value of a minimum air gap value, the second air gap is larger than the minimum air gap value, the second air gap is larger, the magnetic resistance is larger, and the quantity of a magnetic circuit flowing from the rotor core 100 to the stator core 200 and then flowing through the rotor core 100 to the rotor core 200 can be reduced, so that the magnetic flux leakage phenomenon of the rotor core 100 at the magnetic pole alternation position is reduced, and the utilization rate of magnetic steel is improved.

Referring to fig. 11 and 12, when the permanent magnet brushless motor operates, a rotating magnetic field is generated, a magnetic pulling force generated by the rotating magnetic field will generate a tangential force and a radial force to the rotor, the tangential force mainly drives the rotor to rotate, and the radial force can cause the motor to vibrate and generate large vibration noise. The cogging torque reflects the magnitude of the radial magnetic pulling force of the rotor on the stator, and the larger the cogging torque is, the larger the radial magnetic pulling force of the rotor on the stator is. The cogging torque can cause the motor to generate vibration and noise, the rotation speed fluctuation occurs, the motor cannot run stably, the performance of the motor is influenced, and the low-speed performance of the motor in a speed control system and the high-precision positioning of the motor in a position control system are also influenced. As can be seen from comparing fig. 11 and 12, when the rotor core 100 and the stator core 200 in the motor are designed according to the structure of the above embodiment, the cogging torque can be greatly reduced, and thus the vibration of the motor can be reduced, thereby reducing the vibration noise and making the operation thereof more stable.

Referring to fig. 13 and 14, the torque represents the magnitude of the rotating force of the motor, and the torque fluctuation not only causes the vibration of the motor body, but also causes the vibration of the components directly or indirectly contacting with the motor, which is not favorable for the smooth operation of the motor. As can be understood from comparing fig. 13 and 14, when the rotor core 100 and the stator core 200 in the motor are designed according to the structure of the above-described embodiment, the waveform is more gradual, and the torque fluctuation is smaller. Therefore, the vibration of the motor can be reduced, so that the vibration noise is reduced, and the running of the motor is more stable.

Referring to fig. 15 and 16, in fig. 15, the peak of the waveform of the line back electromotive force is a flat-top wave, it can be seen that the performance of the motor is greatly affected by the harmonic wave, the harmonic wave vibration received by the motor is large and the harmonic wave loss is large, when the controller vector controls the motor to commutate, the vibration of the motor is large, and correspondingly, the generated vibration noise is also large. In fig. 16, the wave crest of the waveform of the line back electromotive force is smooth, the waveform tends to be sinusoidal, the performance of the motor is less affected by harmonic waves, the harmonic vibration and the harmonic loss are less, the motor vibration is less when the controller vector controls the motor to commutate, correspondingly, the vibration noise is less, and the motor operates more stably.

Referring to fig. 17 and 18, similar to the above, in fig. 17, the peak of the waveform of the back electromotive force of the load line is a flat-top wave, which is greatly affected by the harmonic. In fig. 18, the wave crest of the waveform of the back electromotive force of the load line is smooth, the waveform tends to be sinusoidal, the performance of the motor is less affected by harmonic waves, the harmonic vibration and the harmonic loss are less, the vibration of the motor is less when the controller vector controls the motor to commutate, correspondingly, the vibration noise is less, and the motor runs more stably.

In addition, tests prove that when the thickness of the rotor core 100 and the stator core 200 in the above embodiment is 20mm, the same output power can be achieved when the thickness is 25mm in the structure shown in fig. 1, that is, the volume is smaller but the output power is the same. It can be seen that when the rotor core 100 and the stator core 200 of the motor are arranged in the above-described structure, the power density is greater. Although the volume is reduced, the effective value of the counter potential and the torque output are not much different from those of the structure shown in fig. 1, and it is explained that the material utilization rate can be improved and the leakage flux can be reduced by using the structure shown in fig. 2.

In summary, in the present embodiment, when the rotor core 100 and the stator core 200 of the motor are arranged according to the above structure, the cogging torque and the torque fluctuation of the motor can be reduced, and the harmonic vibration and the harmonic loss thereof are smaller, so that the vibration of the motor is reduced, the vibration noise is smaller, and the motor operates more stably.

Referring to fig. 2 to 6, the diameter of the first equivalent cylindrical surface 170 is D ₁ The diameter of the second equivalent cylindrical surface 250 is D ₂ A mechanical air gap is formed between rotor teeth 120 and pole shoes 230, and the size of the air gap is δ, D ₂ ＝D ₁ +2 δ. The maximum distance d that the second cambered surface 162 is inwardly offset relative to the first equivalent cylindrical surface 170 is, and the radius of the first cambered surface 161 is R ₄ The radius of the second arc surface 162 is R ₅ . In some embodiments, the parameters described above satisfy the following relationship: 0.1D ₁ ≤R ₄ ≤0.45D ₁ ，0.5D ₁ ≤R ₅ ≤0.9D ₁ D is more than 0 and less than or equal to 2 delta. Multiple tests prove that after all parameters meet the relationship, the reduction range of the cogging torque, the torque fluctuation and the like of the motor is large, the vibration and the vibration noise of the motor can be reduced more remarkably, and the motor can run more remarkablyAnd (4) stabilizing.

Preferably, tests prove that when d is delta, R ₄ ＝0.242D ₁ ，R ₅ ＝0.583D ₁ In the process, parameters in the figures tend to be close to the optimal solution, the reduction range of the cogging torque and the torque fluctuation of the motor is large, and the vibration noise of the motor can be reduced more remarkably, so that the motor runs more stably.

Referring to fig. 2 to 4, the first arc surface 161 is the second axis O ₂ Formed as an axis, the second arc surface 162 being a third axis O ₃ Is formed as a shaft. Second axis O ₂ A third axis O ₃ Are all aligned with the first axis O ₁ Are not coincident. The number of sets of first arcs 161 and second arcs 162 is the same as the number of rotor teeth 120. For example, in the embodiment shown in the drawings, the number of the rotor teeth 120 is 6, and accordingly, the number of the first arc surfaces 161 and the number of the second arc surfaces 162 are both 6. The central angles of the first arc surface 161 and the second arc surface 162 are 2 α and 2 β, respectively, and α + β is 30 °. When the foregoing D ₁ 、D ₂ 、δ、R ₄ 、R ₅ When the values are changed, the specific values of alpha and beta will be changed accordingly. In one particular embodiment shown in the drawings, α is 4 ° and β is 26 °.

In one specific embodiment shown in the drawings, the first arc surfaces 161 are located in a central region of the outer surface of the rotor tooth portion 120 in the circumferential direction, and two adjacent first arc surfaces 161 are connected to each other by a smooth transition of the second arc surface 162. However, the present invention is not limited to this, because the rotor rotates relative to the stator, and therefore, there is no specific requirement for the specific positions of the first arc-shaped surface 161 and the second arc-shaped surface 162 in the circumferential direction. For example, in another specific embodiment, the first arc surfaces 161 are located in the central region of the outer surface between two adjacent rotor teeth 120, and the two adjacent first arc surfaces 161 are connected to each other by the second arc surface 162 in a smooth transition manner. The first arc surface 161 and the second arc surface 162 are in smooth transition, so that sudden change of a larger angle of the outer contour of the rotor core 100 can be avoided, the outer contour of the rotor core 100 is prevented from forming a larger corner, and the magnetic flux leakage problem of the motor is improved.

Referring to fig. 2, 5 to 7, in some embodiments, at the end of the pole shoe 230 of the stator core 200, the second end 232 is a third arc surface, and the second end 232 coincides with the second equivalent cylindrical surface 250 and is a part of the second equivalent cylindrical surface 250. Along the circumferential direction, the first end surface 231 and the third end surface 233 are symmetrically distributed on two sides of the second end surface 232. The first 231 and third 233 end faces are both planar and both tangential to the second equivalent cylindrical surface 250, i.e. both tangential to the second end face 232. In this way, material is cut off at positions corresponding to both sides of the second end surface 232 to form the chamfered shape shown in the drawing. Through the structure, the cogging torque can be reduced, the armature reaction is weakened, and the torque fluctuation is reduced, so that the vibration noise is reduced.

Referring to FIG. 7, in some embodiments, the distance X between the end of the first end surface 231 in the circumferential direction and the second equivalent cylindrical surface 250 ₁ In the range of 0 < X ₁ Less than or equal to 0.6 mm. When the deviation is within the value range, the cogging torque and the torque fluctuation are obviously reduced.

Referring to fig. 8 and 9, in other embodiments, the first end surface 231, the second end surface 232 and the third end surface 233 form a fourth arc surface 234, and the fourth arc surface 234 is a fourth axis O ₄ Formed as a shaft, a fourth axis O ₄ And the first axis O ₁ Are not coincident. In the circumferential direction, the middle region of the fourth arc surface 234 is tangent to the second equivalent cylindrical surface 250, and the two end regions are offset outwards relative to the second equivalent cylindrical surface 250, so that the chamfered shape shown in the drawings can also be formed. Through the structure, the cogging torque can be reduced, the armature reaction is weakened, and the torque fluctuation is reduced, so that the vibration noise is reduced.

Referring to FIG. 9, in some embodiments, the radius R of the fourth arc 234 ₆ In the range of 0 < R ₆ ＜0.825D ₂ The distance X between the end of the fourth cambered surface 234 in the circumferential direction and the second equivalent cylindrical surface 250 ₂ In the range of 0 < X ₂ Less than or equal to 0.6 mm. When the deviation is within the value range, the cogging torque and the torque fluctuation are obviously reduced.

Referring to fig. 5, 6 and 10, the first axis O ₁ Forming a third equivalent cylindrical surface 260 for the shaft, every twoA winding slot 240 is formed between adjacent stator teeth 220, a coil is wound on the stator teeth 220, and the winding slot 240 receives the coil. In some embodiments, the slot bottom wall of the winding slot 240 is a fifth arc 241, the fifth arc 241 being the fifth axis O ₅ Formed as axes, a fifth axis O ₅ And the first axis O ₁ Are not coincident. The fifth cambered surface 241 is tangent to the third equivalent cylindrical surface 260. Specifically, the fifth arc surface 241 includes a fifth arc surface first section 2411, a fifth arc surface second section 2412 and a fifth arc surface third section, and the fifth arc surface first section 2411 and the fifth arc surface third section are symmetrically connected to two ends of the fifth arc surface second section 2412 respectively. The second section 2412 of the fifth cambered surface is tangent to the third equivalent cylindrical surface 260, and the first section 2411 of the fifth cambered surface and the third section of the fifth cambered surface are both inwards close to the first axis O relative to the third equivalent cylindrical surface 260 ₁ Is deviated in direction; it can be understood that the radius of the fifth cambered surface 241 is smaller than that of the third equivalent cylindrical surface 260, and the middle position of the fifth cambered surface 241 is linearly tangent to the third equivalent cylindrical surface 260. In the configuration shown in figure 1 the slot base wall of the winding slot is the third equivalent cylindrical surface 260. The slot bottom wall of the embodiment is arranged in such a way that the magnetic path length L1 of the stator tooth part 220 is smaller than the magnetic path length L2 in the structure of fig. 1, so that the iron loss is reduced, and the motor efficiency is improved. The width W1 of the stator yoke 210 can be made larger than the magnetic path length W2 in the structure of fig. 1, so that the magnetic density and the iron loss are reduced, and the motor efficiency is improved. In addition, because the first section 2411 of the fifth cambered surface and the third section of the fifth cambered surface are both deviated inwards, when winding, the coil can be more easily wound to the tooth root, the groove fullness rate during winding can be improved, and the space waste is reduced. In some embodiments, the diameter D of the third equivalent cylindrical surface 260 ₃ In the range of 1.4D ₁ ＜D ₃ ＜1.65D ₁ Radius R of the fifth cambered surface 241 ₇ In the range of D ₃ /8≤R ₇ ＜D ₃ /2。

Referring to fig. 2 to 4, in some embodiments, the rotor core 100 is provided with a plurality of sets of magnetic steel slots distributed along the circumferential direction, each set of magnetic steel slots includes a first magnetic steel slot portion 131 and a second magnetic steel slot portion 132, the first magnetic steel slot portion 131 and the second magnetic steel slot portion 132 are disposed at an angle, the first magnetic steel slot portion 131 and the second magnetic steel slot portion 132 are in a "V" shape, and a rotor tooth portion 120 is disposed between the first magnetic steel slot portion 131 and the second magnetic steel slot portion 132. The angle W between the first magnetic steel groove portion 131 and the second magnetic steel groove portion 132 ranges from 60 ° ≦ W ≦ 90 °, and may be set to 60 °, 75 °, or 90 °, for example. Compare with the arc magnet steel groove in fig. 1, in this embodiment, first magnet steel slot part 131 is similar to the cuboid with second magnet steel slot part 132, and the shape is more regular, and the processing degree of difficulty is lower, and difficult emergence fracture in the course of working can reduce the processing cost. Or, in other embodiments, the magnetic steel groove may also be "U" shaped, three magnetic steels are disposed in the magnetic steel groove, and the three magnetic steels are integrally "U" shaped.

First magnet steel 310 blocks into first magnet steel slot portion 131, and second magnet steel 320 blocks into second magnet steel slot portion 132, and the joint structure dismouting is comparatively convenient. The first magnetic steel 310 and the second magnetic steel 320 have the same polarity, and after the installation is completed, the two positions are in a V shape. Compare with the arc magnet steel in figure 1, the mode magnet steel groove in this embodiment is ferrite V type groove, belongs to the off-state between two magnet steels, can increase the magnetic flux that the magnet steel produced in the finite space, helps reducing motor volume, and then reduce cost. In a specific embodiment, the first magnetic steel 310 and the second magnetic steel 320 are in contact with each other after being mounted. In another specific embodiment, after the first magnetic steel 310 and the second magnetic steel 320 are mounted, there is a gap between them.

Specifically, in some embodiments, the first magnetic steel slot 131 and the second magnetic steel slot 132 are located radially outside the rotor yoke 110, the rotor yoke 110 is provided with the first preload member 111 and the second preload member 112, the first preload member 111 protrudes into the first magnetic steel slot 131, and the second preload member 112 protrudes into the second magnetic steel slot 132. Bosses 140 are further provided at the outer end of rotor core 100, and each first magnetic steel groove portion 131 shares one boss 140 with a second magnetic steel groove portion 132 in an adjacent magnetic steel groove. Two ends of the first magnetic steel 310 respectively abut against the first preload member 111 and the boss 140, and two ends of the second magnetic steel 320 respectively abut against the second preload member 112 and the boss 140. After the installation is completed, the two ends of the first magnetic steel 310 and the second magnetic steel 320 are both abutted and fixed, so that the position deviation is not easy to occur, and the unbalance change caused by the displacement of the first magnetic steel 310 and the second magnetic steel 320 and the vibration noise generated by the unbalance change are effectively reduced. Preferably, the first preload part 111 and the second preload part 112 have elasticity, and can elastically deform to elastically support the first magnetic steel 310 and the second magnetic steel 320, so that compared with rigid support, the elastic support can prevent the first magnetic steel 310 and the second magnetic steel 320 from being damaged, and the first magnetic steel 310 and the second magnetic steel 320 can be easily clamped during installation.

Preferably, the boss 140 protrudes from the side walls of the first magnetic steel groove portion 131 and the second magnetic steel groove portion 132. Taking the first magnetic steel 310 as an example, compared with directly abutting the first magnetic steel 310 against the side wall of the first magnetic steel slot portion 131, when the boss 140 abuts against the first preload member 131 for installation, the second gap 152 exists between the first magnetic steel 310 and the side wall of the first magnetic steel slot portion 131. A magnetic isolation bridge may be formed at the second gap 152, which can reduce magnetic leakage and increase power density of the motor. Similarly, a first gap 151 exists between the first magnetic steel 310 and the rotor yoke 110, that is, on both sides of the first preload member 131, and a magnetic isolation bridge can be formed at the first gap 151, so that magnetic leakage can be reduced, and the power density of the motor can be increased.

In some embodiments, a household appliance is further included, the household appliance comprising the motor in any of the above embodiments, and the household appliance has the advantages of the motor in any of the above embodiments. For example, the home appliance may be a washing machine, an electric fan, an air conditioner, or the like.

In some embodiments, a garden tool is further included, the garden tool comprising the motor in any of the above embodiments, the garden tool having the benefits of the motor in any of the above embodiments. For example, the garden tool may be a lawn mower or the like.

In some embodiments, a vehicle is also included, the vehicle comprising the motor of any of the above embodiments, the vehicle having the benefits of the motor of any of the above embodiments. For example, the vehicle may be an electric vehicle or the like.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. An electric machine, comprising:

the motor outputs power through the rotor shaft, the outer peripheral surface of the rotor core comprises a first cambered surface and a second cambered surface which are alternately distributed along the circumferential direction, a first equivalent cylindrical surface is formed by taking the center of the rotor core as a first axis, the first cambered surface is tangent to the first equivalent cylindrical surface, and the second cambered surface is offset towards the center of the rotor core relative to the first equivalent cylindrical surface;

the stator is fixedly connected with the shell, and the rotor shaft is connected with the shell through a bearing.

2. According to claim 1The motor is characterized in that the diameter of the first equivalent cylindrical surface is D ₁ The diameter of the second equivalent cylindrical surface is D ₂ The mechanical air gap of the motor is delta, the offset distance of the second cambered surface relative to the first equivalent cylindrical surface is d, and the radius of the first cambered surface is R ₄ The radius of the second cambered surface is R ₅ ，D ₂ ＝D ₁ +2δ，0.1D ₁ ≤R ₄ ≤0.45D ₁ ，0.5D ₁ ≤R ₅ ≤0.9D ₁ ，0＜d≤2δ。

3. The machine of claim 2, wherein d δ, R ₄ ＝0.242D ₁ ，R ₅ ＝0.583D ₁ 。

4. The electric machine of claim 1, wherein the second end surface is a third arc surface coincident with the second equivalent cylindrical surface, and the first end surface and the third end surface are planes tangent to the second equivalent cylindrical surface.

5. The electric machine of claim 4, wherein the first end surface and the third end surface are symmetrically distributed on two sides of the second end surface, and a distance X between an end of the first end surface in the circumferential direction and the second equivalent cylindrical surface ₁ In the range of 0 < X ₁ ≤0.6mm。

6. The electric machine of claim 1, wherein the first end face, the second end face, and the third end face form a fourth arc face, an axis of the fourth arc face being offset from the first axis.

7. The electric machine of claim 6, wherein the radius R of the fourth arc surface ₆ In the range of 0 < R ₆ ＜0.825D ₂ The distance X between the end part of the fourth cambered surface along the circumferential direction and the second equivalent cylindrical surface ₂ In the range of 0 < X ₂ ≤0.6mm。

8. The electric machine according to claim 1, wherein a third equivalent cylindrical surface is formed by taking the first axis as an axis, a winding slot is formed between adjacent stator tooth portions, a slot bottom wall of the winding slot is a fifth cambered surface, the fifth cambered surface comprises a fifth cambered surface first section, a fifth cambered surface second section and a fifth cambered surface third section which are sequentially connected along the circumferential direction, the fifth cambered surface second section is tangent to the third equivalent cylindrical surface, and the fifth cambered surface first section, the fifth cambered surface third section are both offset towards the center of the rotor core relative to the third equivalent cylindrical surface;

preferably, the diameter D of the third equivalent cylindrical surface ₃ In the range of 1.4D ₁ ＜D ₃ ＜1.65D ₁ Radius R of the fifth arc surface ₇ In the range of D ₃ /8≤R ₇ ＜D ₃ /2。

9. The motor of claim 1, wherein the rotor core is provided with a plurality of sets of circumferentially distributed magnetic steel slots, each magnetic steel slot comprises a first magnetic steel slot and a second magnetic steel slot, the first magnetic steel slot and the second magnetic steel slot are arranged at an angle, a rotor tooth portion is arranged between each first magnetic steel slot and the second magnetic steel slot, a first magnetic steel is clamped in the first magnetic steel slot, and a second magnetic steel is clamped in the second magnetic steel slot;

preferably, the rotor core further includes a rotor yoke portion, the magnet steel slot is located at an outer side of the rotor yoke portion along a radial direction, the rotor yoke portion is provided with a first pre-tightening member protruding toward the first magnet steel slot portion and a second pre-tightening member protruding toward the second magnet steel slot portion, a boss protruding toward the first magnet steel slot portion and the second magnet steel slot portion of the adjacent magnet steel slot is arranged at an outer end of the rotor core along the radial direction, two ends of the first magnet steel respectively abut against the first pre-tightening member and the boss, and two ends of the second magnet steel respectively abut against the second pre-tightening member and the boss;

preferably, the boss protrudes from the side walls of the first magnetic steel groove and the second magnetic steel groove.

10. Household appliance, garden tool or vehicle, characterized in that it comprises a motor according to any one of claims 1 to 9.