Rotor core, rotor assembly, motor and food processor

Abstract

The utility model discloses a rotor core, a rotor assembly, a motor and a food processor. First auxiliary grooves are formed in the peripheral face of the rotor core, two first auxiliary grooves are formed corresponding to the same magnetic pole, the two first auxiliary grooves are symmetrically arranged relative to the center line of the magnetic pole, and the first auxiliary grooves extend in the axial direction of the rotor core. The section, perpendicular to the axis of the rotor core, of the groove wall face of the first auxiliary groove is a part of an ellipse, the connecting line of the center of the ellipse and the axis of the rotor core is an auxiliary line, the long axis of the ellipse is perpendicular to the auxiliary line, and the short axis of the ellipse coincides with the auxiliary line. According to the rotor core provided by the embodiment of the utility model, the first auxiliary groove is arranged on the outer peripheral surface of the rotor core, the first auxiliary groove is optimized, and an air gap flux density function is adjusted, so that the sine degree of the air gap flux density is optimized, the cogging torque and the radial electromagnetic force are reduced, and the stability of the rotor core is improved. Therefore, the vibration noise of the motor is reduced, and the output performance of the motor is not affected.

Description

TECHNICAL FIELD

[0001] The utility model relates to motor technical field more particularly, relate to a rotor core, rotor assembly, motor and food processor. BACKGROUND

[0002] With the improvement of life quality, the user has put forward higher requirement to the noise and performance of food processor. As the core power component of food processor, motor is closely related to vibration noise and service life.

[0003] In the related art, when the permanent magnet motor operates, it will generate large vibration noise and affect the motor operation reliability, which affects the vibration noise and service life of the food processor using the permanent magnet motor. SUMMARY

[0004] The utility model discloses at least one of the technical problems existing in the prior art. To this end, one purpose of the utility model is to provide a rotor core, which reduces the vibration noise of motor operation.

[0005] The utility model discloses further provide a rotor assembly with above-mentioned rotor core.

[0006] The utility model discloses further provide a motor with above-mentioned rotor assembly.

[0007] The utility model discloses further provide a food processor with above-mentioned motor.

[0008] According to the rotor core of the utility model embodiment, the outer circumferential surface of the rotor core is provided with a first auxiliary groove, two first auxiliary grooves are provided corresponding to the same magnetic pole, and the two first auxiliary grooves are symmetrically arranged about the midline of the magnetic pole, the first auxiliary groove extends along the axial direction of the rotor core, the cross section of the groove wall surface of the first auxiliary groove is perpendicular to the axis of the rotor core Elliptical part, the center line of the elliptical shape and the axis of the rotor core is an auxiliary line, the major axis of the elliptical shape is perpendicular to the auxiliary line, and the minor axis of the elliptical shape coincides with the auxiliary line.

[0009] According to the rotor core of the utility model embodiment, by setting the first auxiliary groove on the outer circumferential surface of the rotor core, and optimizing the shape and structure of the first auxiliary groove, the air gap magnetic density function is adjusted, and the sine degree of the air gap magnetic density is optimized, which is beneficial to reduce the tooth slot torque and radial electromagnetic force, and further reduce the vibration noise of the motor, and will not have adverse effects on the output performance of the motor.

[0010] In addition, the rotor core according to the above embodiment of the utility model can also have the following additional technical features:

[0011] According to some embodiments of the present application, the included angle between the auxiliary line and the middle line of the magnetic pole is θ, and θ is greater than or equal to t p / 5 and less than or equal to t p / 4, wherein t p is the pole pitch.

[0012] According to some embodiments of the present application, the long semi-axis length of the ellipse is greater than or equal to 2mm and less than or equal to 3mm.

[0013] According to some embodiments of the present application, the short semi-axis length of the ellipse is greater than or equal to 0.3mm and less than or equal to 0.5mm.

[0014] According to some embodiments of the present application, the rotor core is provided with a mounting groove for mounting the permanent magnet, the mounting groove extends perpendicularly to the middle line of the magnetic pole, and both ends of the mounting groove are respectively provided with air grooves, the distance between one end of the first auxiliary groove close to the middle line of the magnetic pole and the mounting groove is L1, the distance between the first auxiliary groove and the end of the mounting groove is L2, and L1 is greater than L2; and / or, the distance between the first auxiliary groove and the air groove increases in the direction away from the middle line of the magnetic pole.

[0015] According to some embodiments of the present application, the outer circumferential surface of the rotor core is provided with a second auxiliary groove, the second auxiliary groove extends along the axial direction of the rotor core, one magnetic pole is provided with one second auxiliary groove, and the second auxiliary groove is symmetrical about the middle line of the corresponding magnetic pole.

[0016] According to some embodiments of the present application, the cross section of the groove wall surface of the second auxiliary groove perpendicularly to the rotor core axis is a part of a circle.

[0017] According to some embodiments of the present application, the distance between the center of the circle and the axis of the rotor core is La, the radius of the circle is Ra, and the radius of the outer circumferential surface of the rotor core is Rr, wherein Rr-(La-Ra) is greater than or equal to 0.2mm and less than or equal to 0.8mm.

[0018] The rotor assembly according to the embodiments of the present application comprises a permanent magnet and a rotor core according to the embodiments of the present application, the rotor core is provided with a mounting groove extending along the axial direction, and the permanent magnet is mounted in the mounting groove.

[0019] The motor according to the embodiments of the present application comprises a rotor assembly according to the embodiments of the present application.

[0020] According to some embodiments of the present application, the motor is a 10-pole 12-slot motor.

[0021] The food processor according to the embodiments of the present application comprises the motor according to the embodiments of the present application.

[0022] Additional aspects and advantages of the present application will be described in the following description, become apparent from it, or be learned by practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0023] The above and / or additional aspects and advantages of the present application will become apparent and be readily understood from the following description, taken in conjunction with the accompanying drawings, in which:

[0024] Figure 1 is an axial structure schematic view of a rotor core according to some embodiments of the present application;

[0025] Figure 2 is a local structure schematic view of a rotor core corresponding to one magnetic pole according to some embodiments of the present application;

[0026] Figure 3 is a structure schematic view of a rotor core according to other embodiments of the present application;

[0027] Figure 4 is an axial structure schematic view of a rotor core according to other embodiments of the present application;

[0028] Figure 5 is a local structure schematic view of a rotor core corresponding to one magnetic pole according to other embodiments of the present application;

[0029] Figure 6 is a tooth slot torque test diagram of the embodiments and the comparative examples of the present application;

[0030] Figure 7 is a radial air gap magnetic flux density and harmonic analysis of the embodiments and the comparative examples of the present application;

[0031] Figure 8 is a stator tooth part certain point radial electromagnetic force density and harmonic analysis of the embodiments and the comparative examples of the present application;

[0032] Figure 9 is an electromagnetic torque test diagram when Id=0 control method and MTPA control method are adopted by the embodiments and the comparative examples of the present application;

[0033] Figure 10 is a θ angle optimization curve diagram of the first auxiliary groove according to the embodiments of the present application;

[0034] Figure 11 is a long semi-axis optimization curve diagram of the first auxiliary groove according to the embodiments of the present application, wherein θ= tp / 4;

[0035] Figure 12 is a short semi-axis optimization curve diagram of the first auxiliary groove according to the embodiment of the utility model, wherein θ= t p / 4, Lb=2.7mm;

[0036] Figure 13 is the Rr-(La-Ra) optimization curve diagram of the second auxiliary groove according to the embodiment of the utility model;

[0037] Figure 14 is a partial structure schematic diagram of the motor according to the embodiment of the utility model.

[0038] Reference signs:

[0039] Motor 100;

[0040] Rotor core 10;

[0041] Midline A of magnetic pole; auxiliary line B;

[0042] First auxiliary groove 11;Second auxiliary groove 12;Mounting groove 13;Air slot 14;

[0043] Rotor assembly 20;Permanent magnet 21;

[0044] Stator assembly 30. DETAILED DESCRIPTION

[0045] The embodiments of the utility model are described in detail below, and the examples of the embodiments are shown in the drawings, wherein the same or similar reference signs represent the same or similar elements or elements with the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary, only for explaining the utility model, and cannot be understood as limiting the utility model.

[0046] In the description of the utility model, it is understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the utility model and simplifying the description, and is not indicative or implied that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the utility model.

[0047] In the description of the utility model, "first feature", "second feature" can include one or more features, "multiple" means two or more, the "above" or "below" of the first feature in the second feature can include that the first and second features are in direct contact, or the first and second features are not in direct contact but are in contact through another feature between them, the "above", "over" and "on" of the first feature in the second feature include that the first feature is directly above and obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature.

[0048] With the improvement of life quality, users have higher requirements for the noise and performance of the food processor. As the core power component of the food processor, the motor is closely related to vibration noise and service life. At present, the food processor on the market mainly uses brush DC motor. Compared with brush DC motor, permanent magnet motor has the advantages of long service life, low noise, high efficiency, adjustable speed, light and thin structure, no carbon powder pollution, etc. However, due to the high cost of the motor, its application is limited. With the restriction of China's rare earth resource export, the price of rare earth has been gradually declining in recent years, and the cost reduction of permanent magnet motor provides further expansion space for its application scenarios.

[0049] In the related art, when the permanent magnet motor operates, due to the influence of the cogging torque, torque ripple and radial magnetic pull, a large vibration noise is generated and the operation reliability of the motor is affected.

[0050] Based on this, the application provides a rotor core 10, which can effectively weaken the cogging torque and radial electromagnetic force of the motor 100 without reducing the output performance of the motor 100, so as to make the motor 100 operate with lower vibration noise.

[0051] The motor 100 adopting the rotor core 10 of the utility model embodiment can be used in devices such as food processors that need to be driven by the motor 100, so as to meet the requirements of low vibration noise and long service life of the food processor and other devices.

[0052] The rotor core 10, the rotor assembly 20 and the motor 100 according to the utility model embodiments are described below with reference to the drawings. The rotor assembly 20 according to the utility model embodiments comprises the rotor core 10 and the permanent magnet 21 mounted on the rotor core 10, and the motor 100 according to the utility model embodiments comprises the rotor assembly 20 according to the utility model embodiments.

[0053] The motor 100 can further comprise a stator assembly 30, the rotor assembly 20 can be mounted in the stator hole of the stator assembly 30, and the rotor assembly 20 cooperates with the stator assembly 30 to make the rotor assembly 20 rotate relative to the stator assembly 30.

[0054] Reference Figures 1-5As shown, according to the rotor core 10 of the embodiment of the utility model, the outer circumferential surface of the rotor core 10 is provided with a first auxiliary groove 11. Two first auxiliary grooves 11 are provided corresponding to the same magnetic pole and the two first auxiliary grooves 11 are symmetrically arranged about the midline A of the magnetic pole. The first auxiliary groove 11 extends along the axial direction of the rotor core 10, and the cross section of the groove wall surface of the first auxiliary groove 11 perpendicular to the axis of the rotor core 10 is a part of an ellipse. The line connecting the center of the ellipse with the axis of the rotor core 10 is an auxiliary line B, the major axis of the ellipse is perpendicular to the auxiliary line B, and the minor axis of the ellipse coincides with the auxiliary line B.

[0055] When the rotor core 10 is used in the rotor assembly 20 of the motor 100, the space between the outer circumferential surface of the rotor core 10 and the inner circumferential surface of the stator hole of the stator assembly 30 constitutes an air gap structure. In the related art, the air gap structure is uniform. Due to the existence of the stator core slot, during the operation of the motor, the interaction between the stator tooth portion and the permanent magnet will cause the change of the magnetic field, thereby causing the deterioration of the cogging torque and the air gap flux density distortion rate, and further increasing the vibration noise of the motor.

[0056] In the present application, the first auxiliary groove 11 is opened on the outer circumferential surface of the rotor core 10, and the shape and structure of the first auxiliary groove 11 are optimized, so that the air gap structure is changed to a non-uniform structure, and the cogging torque, radial electromagnetic force and air gap flux density of the motor 100 are optimized under the condition that the performance of the motor 100 is not reduced, the cogging torque and radial electromagnetic force are weakened, the distortion rate of the air gap flux density is reduced, and the vibration noise of the motor 100 is reduced.

[0057] The effect of the present application will be described below in combination with the performance test of the comparative example and the embodiment of the present application.

[0058] Among them, in the comparative example 1, the outer circumferential surface of the rotor core 10 is not provided with an auxiliary groove; in the embodiment 1 of the present application, the outer circumferential surface of the rotor core 10 is provided with a first auxiliary groove 11. As shown in Figure 6 The tooth slot torque test diagram of the embodiment of the utility model and the comparative example is shown as follows; Figure 7 The radial air gap flux density and harmonic analysis of the embodiment of the utility model and the comparative example is shown as follows; Figure 8 The stator tooth portion point radial electromagnetic force density and harmonic analysis of the embodiment of the utility model and the comparative example is shown as follows; Figure 9 The electromagnetic torque test diagram when the embodiment of the utility model and the comparative example adopt Id=0 control method (d-axis current is excitation current, and q-axis current generates torque) and MTPA control method (maximum torque current ratio control method) is shown as follows.

[0059] Compared with the comparative example 1, by setting the first auxiliary groove 11, in combination with Figure 6 It can be seen that the cogging torque of the motor 100 is reduced; in combination with Figure 7It can be seen that the distortion rate of the radial air gap magnetic flux is significantly reduced, mainly because the third harmonic content is reduced, and the fundamental magnetic flux amplitude is also increased; combined with Figure 8 It can be seen that the two-fold radial electromagnetic force, which mainly affects the motor 100 vibration noise, is significantly reduced; combined with Figure 9 It can be seen that when the Id=0 control method is adopted, the performance of the high-speed section is significantly improved under the condition of ensuring that the performance of the low-speed section does not attenuate, and when the MTPA control method is adopted, the performance of the low-speed section is slightly attenuated, and the performance of the high-speed section is improved.

[0060] In summary, after the first auxiliary groove 11 is set and optimized, the cogging torque and the radial electromagnetic force of the motor 100 are reduced, and the sinusoidal degree of the air gap magnetic flux and the output performance of the motor 100 are improved.

[0061] According to the rotor core 10 of the embodiment of the utility model, by setting the first auxiliary groove 11 on the outer circumferential surface of the rotor core 10, and optimizing the shape and structure of the first auxiliary groove 11, the air gap magnetic flux function is adjusted, and then the sinusoidal degree of the air gap magnetic flux is optimized, which is beneficial to reduce the cogging torque and the radial electromagnetic force, and then reduce the vibration noise of the motor 100, and will not have adverse effects on the output performance of the motor 100.

[0062] According to some embodiments of the utility model, as shown in Figure 1 and Figure 2 , the angle between the auxiliary line B and the middle line A of the corresponding magnetic pole is θ, θ is greater than or equal to t p / 5 and less than or equal to t p / 4, wherein, t p is the pole pitch. That is, t p =π / p, p is the pole pair number of the motor 100.

[0063] By adjusting the angle θ, the distribution position of the first auxiliary groove 11 can be changed, and combined with Figure 10 It can be seen that when the θ angle is too small, although the cogging torque is reduced, the direct-axis magnetic circuit resistance is increased, which will cause the utilization rate of the permanent magnet 21 to decrease; when the θ angle is too large, the first auxiliary groove 11 will affect the thickness of the permanent magnet 21 radial outer side magnetic bridge, and then reduce the mechanical strength of the rotor core 10, which is easy to cause the permanent magnet 21 to be assembled badly.

[0064] The θ angle is in the range of t p / 5, t p / 4, which can obtain higher permanent magnet flux and lower cogging torque, while meeting the mechanical strength requirements of the rotor core 10. For example, in some specific embodiments, the θ angle can bet p / 5、5 t p / 24、2 t p / 9、 t p / 4 etc.

[0065] In some embodiments, such as Figure 2 As shown, the length of the major semi-axis of the ellipse is greater than or equal to 2mm and less than or equal to 3mm, that is, 2mm≤Lb≤3mm.

[0066] The length of the major semi-axis of the ellipse can change the width of the first auxiliary groove 11, such as... Figure 11 As shown, based on the position angle θ, the width of the first auxiliary groove 11 has a relatively small impact on the permanent magnet flux linkage, but a significant impact on the cogging torque. Without affecting the strength of the rotor core 10, Lb within the aforementioned value range is more conducive to reducing the cogging torque and ensuring the mechanical strength of the rotor core 10. For example, in some specific embodiments, the length of the major semi-axis of the ellipse, Lb, can be 2mm, 2.3mm, 2.5mm, 2.8mm, and 3mm, etc.

[0067] In some embodiments, continue to refer to Figure 2 As shown, the length of the minor semi-axis of the ellipse is greater than or equal to 0.3 mm and less than or equal to 0.5 mm, that is, 0.3 mm ≤ Wb ≤ 0.5 mm.

[0068] The length of the minor semi-axis of the ellipse can change the depth of the first auxiliary groove 11, such as... Figure 12 As shown, based on the position angle θ, the depth dimension of the first auxiliary groove 11 has little impact on the permanent magnet flux linkage, while the cogging torque is better in the range of 0.3mm to 0.5mm. For example, in some specific embodiments, the length Wb of the elliptical minor axis can be 0.3mm, 0.35mm, 0.4mm, 0.45mm, and 0.5mm, etc.

[0069] According to some embodiments of this utility model, such as Figure 2 and Figure 5 As shown, the rotor core 10 is provided with a mounting groove 13 for mounting permanent magnets 21. The mounting groove 13 extends perpendicularly to the center line A of the magnetic poles and air grooves 14 are provided at both ends of the mounting groove 13. That is, the permanent magnets 21 are formed into a straight line permanent magnet. The straight line permanent magnets are installed in the mounting groove 13, and air grooves 14 are provided at both ends of the straight line permanent magnets along the circumference of the rotor core 10.

[0070] The first auxiliary groove 11 is partially located on the radial outer side of the mounting groove 13 and partially located on the radial outer side of the air groove 14. The distance between the end of the first auxiliary groove 11 close to the center line A of the magnetic pole and the mounting groove 13 is L1, and the distance between the end of the first auxiliary groove 11 and the mounting groove 13 is L2, and L1 is greater than L2. Therefore, the first auxiliary groove 11 is arranged obliquely relative to the center line A of the magnetic pole, so that the distance between different positions of the first auxiliary groove 11 and the permanent magnet 21 is different, the non-uniformity of the air gap is better, and the effect of improving the sine degree of the air gap magnetic flux density is better, which is more conducive to reducing the vibration noise of the motor 100.

[0071] In addition, the distance between the first auxiliary groove 11 and the air groove 14 increases in the direction away from the center line A of the magnetic pole, so that the width (i.e. the dimension in the radial direction of the rotor core 10) of the magnetic bridge between the air groove 14 and the outer circumferential surface of the rotor core 10 is not too small, and the mechanical strength of the rotor core 10 is ensured.

[0072] According to some embodiments of the utility model, as shown in Figures 3-5 The outer circumferential surface of the rotor core 10 is also provided with a second auxiliary groove 12, and the second auxiliary groove 12 extends in the axial direction of the rotor core 10. One second auxiliary groove 12 is arranged corresponding to one magnetic pole, and the second auxiliary groove 12 is symmetrical about the center line A of the corresponding magnetic pole.

[0073] By arranging the second auxiliary groove 12 passing through the center line A of the magnetic pole, the second auxiliary groove 12 cooperates with the first auxiliary groove 11, which is more conducive to the optimization of the cogging torque, the radial electromagnetic force and the air gap magnetic flux density of the motor 100.

[0074] The effects of the above-mentioned embodiments of the application will be described below in combination with the performance tests of the comparative examples and the embodiments of the application. In comparative example 2, only the second auxiliary groove 12 is arranged on the outer circumferential surface of the rotor core 10; in the embodiment 2 of the application, the first auxiliary groove 11 and the second auxiliary groove 12 are arranged on the outer circumferential surface of the rotor core 10.

[0075] In combination with Figure 6 It can be seen that, compared with comparative example 1, when only the first auxiliary groove 11 or only the second auxiliary groove 12 is arranged, the cogging torque is reduced, but when the first auxiliary groove 11 and the second auxiliary groove 12 are arranged at the same time, the effect of reducing the cogging torque is better. In combination with Figure 7 It can be seen that, when only the second auxiliary groove 12 is arranged, the distortion rate of the radial air gap magnetic flux density increases, and when the first auxiliary groove 11 or the first auxiliary groove 11 and the second auxiliary groove 12 are arranged at the same time, the distortion rate of the radial air gap magnetic flux density decreases significantly, mainly because the third harmonic content is reduced, and the fundamental magnetic flux amplitude also increases. In combination with Figure 8It can be seen that the second auxiliary groove 12 has a certain effect on the vibration noise of the motor 100, and the second-order frequency radial electromagnetic force, which mainly affects the vibration noise of the motor 100, is reduced. The first auxiliary groove 11 or the first auxiliary groove 11 and the second auxiliary groove 12 can greatly reduce the second-order frequency radial electromagnetic force. In combination with Figure 9 It can be seen that when the Id=0 control method is used, the performance of the low-speed stage is reduced when only the second auxiliary groove 12 is used, and the performance of the high-speed stage is improved. When the first auxiliary groove 11 is introduced, the performance of the low-speed stage is not attenuated, and the performance of the high-speed stage is significantly improved. When the MTPA control method is used, the performance of the full-speed stage is reduced when only the second auxiliary groove 12 is used. When the first auxiliary groove 11 is introduced, the performance of the low-speed stage is slightly attenuated, and the performance of the high-speed stage is improved.

[0076] In summary, the first auxiliary groove 11 and the second auxiliary groove 12 are provided at the same time, the cogging torque and the radial electromagnetic force of the motor 100 are reduced, and the sinusoidal degree of the air gap magnetic flux density and the output performance of the motor 100 are improved, which is beneficial to reduce the vibration noise of the motor 100.

[0077] The specific shape of the second auxiliary groove 12 can be flexibly set according to actual conditions. For example, in some embodiments, as shown in Figure 4 and Figure 5 The cross section of the second auxiliary groove 12 perpendicular to the axis of the rotor core 10 is a part of a circle. The circle is symmetrical about the center line A of the magnetic pole, that is, the center line A of the magnetic pole passes through the center of the circle. The second auxiliary groove 12 is formed as a circular groove, which is easier to process and is beneficial to ensure the mechanical strength of the rotor core 10.

[0078] In some specific embodiments, as shown in Figure 5 The distance between the center of the circle and the axis of the rotor core 10 is La, the radius of the circle is Ra, and the radius of the outer circumferential surface of the rotor core 10 is Rr, wherein Rr-(La-Ra) is greater than or equal to 0.2mm and less than or equal to 0.8mm.

[0079] The radius of the circle and the distance between the center of the circle and the axis of the rotor core 10 will affect the position and depth of the second auxiliary groove 12, and further affect the magnetic resistance of the magnetic circuit. If the second auxiliary groove 12 is too large and too deep, it will affect the rotor magnetic circuit. If it is too shallow and too small, it may not be obvious that the performance optimization effect is not obvious.

[0080] In combination with Figure 13 It can be seen that when La-Ra is too large, the performance optimization effect of the second auxiliary groove 12 is not obvious, and when La-Ra is too small, on the one hand, the direct-axis magnetic resistance increases, which will lead to the reduction of the permanent magnet flux linkage, and further affect the output performance of the motor 100. On the other hand, the mechanical strength of the rotor core 10 will also be affected.

[0081] Rr-(La-Ra) is in the range of 0.2mm-0.8mm, which is more conducive to obtaining higher permanent magnet flux linkage and lower cogging torque, while the mechanical strength of the rotor core 10 and the output performance of the motor 100 are taken into account. For example, in some specific embodiments, Rr-(La-Ra) can be 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm and 0.8mm, etc.

[0082] As shown in Figure 14 The rotor assembly 20 according to the embodiment of the utility model, including permanent magnet 21 and the rotor core 10 according to the embodiment of the utility model, the rotor core 10 is equipped with the installation groove 13 along the axial extension, and the permanent magnet 21 is installed in the installation groove 13. Since the rotor core 10 according to the embodiment of the utility model has the beneficial technical effects described above, the rotor assembly 20 according to the embodiment of the utility model, by setting the first auxiliary groove 11 on the outer circumferential surface of the rotor core 10, and optimizing the shape and structure of the first auxiliary groove 11, adjusting the air gap flux function, and further optimizing the sinusoidal degree of the air gap flux, is conducive to reducing the cogging torque and radial electromagnetic force, thereby reducing the vibration noise of the motor 100, and will not adversely affect the output performance of the motor 100.

[0083] By setting the permanent magnet 21, the motor 100 with the above rotor assembly 20 is formed into a permanent magnet motor 100, which has the advantages of long service life, low noise, high efficiency, adjustable speed, light and thin structure, no carbon powder pollution, etc. compared with the brush DC motor in the related art.

[0084] In the embodiment of the present application, the permanent magnet 21 corresponding to each magnetic pole can be a one-letter type permanent magnet as shown in Figure 14 , or a V-shaped permanent magnet, a U-shaped permanent magnet or other structure permanent magnet 21, etc. The installation groove 13 on the corresponding rotor core 10 can be adaptively set according to the structure of the permanent magnet 21.

[0085] As shown in Figure 14 The motor 100 according to the embodiment of the utility model, including the rotor assembly 20 according to the embodiment of the utility model. Since the rotor assembly 20 according to the embodiment of the utility model has the beneficial technical effects described above, the motor 100 according to the embodiment of the utility model, by setting the first auxiliary groove 11 on the outer circumferential surface of the rotor core 10, and optimizing the shape and structure of the first auxiliary groove 11, adjusting the air gap flux function, and further optimizing the sinusoidal degree of the air gap flux, is conducive to reducing the cogging torque and radial electromagnetic force, thereby reducing the vibration noise of the motor 100, and will not adversely affect the output performance of the motor 100.

[0086] In some embodiments, the motor 100 is a 10-pole 12-slot motor 100. The pole number and slot number of the motor 100 described above are more matched with the shape and size design of the auxiliary grooves (such as the first auxiliary groove 11) on the rotor core 10, the effect of improving the output performance of the motor 100, weakening the cogging torque and radial electromagnetic force is better, and the noise reduction effect is also better. Moreover, the above motor 100 can better meet the use requirements of small household appliances such as food processors.

[0087] According to the motor 100 of the food processor, the first auxiliary groove 11 is arranged on the outer circumferential surface of the rotor core 10, and the shape and structure of the first auxiliary groove 11 are optimized, the air gap magnetic density function is adjusted, and then the sinusoidal degree of the air gap magnetic density is optimized, which is beneficial to reduce the cogging torque and radial electromagnetic force, thereby reducing the vibration noise of the motor 100, and without adversely affecting the output performance of the motor 100.

[0088] The food processor can be used for at least one of cutting, mincing, grinding, breaking, heating and other functions of food materials, for example, the food processor in some embodiments can have the functions of making soy milk, grinding dry powder, juicing, making meat stuffing, and shaving ice.

[0089] The motor 100 of the food processor according to one specific embodiment of the present application will be described in detail below with reference to the accompanying drawings, and it should be understood that the following description is only exemplary and cannot be construed as limiting the application.

[0090] As shown in Figures 3-5 and Figure 14 The motor 100 of the food processor according to one specific embodiment of the present application includes a stator assembly 30 and a rotor assembly 20, and the rotor assembly 20 is located in the stator hole of the stator assembly 30. The rotor assembly 20 includes a rotor core 10 and a plurality of permanent magnets 21 evenly distributed along the circumferential direction of the rotor core 10, and the permanent magnets 21 are installed in the mounting groove 13 of the rotor core 10 and fixed by suction force and filling glue. When the motor 100 is running, the permanent magnets 21 make circular motion around the axis with the rotor core 10, and the positions of the two remain unchanged.

[0091] The outer circumferential surface of the rotor core 10 is provided with a first auxiliary groove 11 and a second auxiliary groove 12, and by arranging the first auxiliary groove 11 and the second auxiliary groove 12, the air gap structure between the rotor core 10 and the stator assembly 30 is changed to an uneven structure, and the cogging torque, radial electromagnetic force and air gap magnetic density of the motor 100 are optimized under the condition of ensuring that the performance of the motor 100 is not reduced.

[0092] The positions, widths and depths of the first auxiliary grooves 11 and the second auxiliary grooves 12 should be properly set, the positions of the first auxiliary grooves 11 and the second auxiliary grooves 12 affect the magnetic resistances of the direct-axis and quadrature-axis magnetic circuits, the widths and depths greatly affect the optimization results, too deep will affect the rotor magnetic circuit, too shallow and too small will not have obvious optimization effect.

[0093] The first auxiliary grooves 11 are elliptical grooves, that is, the cross section of the groove wall surface of the first auxiliary grooves 11 perpendicular to the axis of the rotor core 10 is a part of an ellipse. Two first auxiliary grooves 11 are arranged corresponding to each magnetic pole, and the two first auxiliary grooves 11 are symmetrically distributed about the center line A of the magnetic pole. That is, the number of the first auxiliary grooves 11 is 4p, and p is the pole pair number of the motor 100. The distribution position of the first auxiliary grooves 11 can be changed by adjusting the angle θ, and the width and depth of the first auxiliary grooves 11 can be changed by adjusting the length Lb of the long semi-axis and the length Wb of the short semi-axis.

[0094] The second auxiliary grooves 12 are circular grooves, that is, the cross section of the groove wall surface of the second auxiliary grooves 12 perpendicular to the axis of the rotor core 10 is a part of a circle. One second auxiliary groove 12 is arranged corresponding to each magnetic pole, and the second auxiliary groove 12 is arranged at the position of the center line A of the magnetic pole. That is, the number of the second auxiliary grooves 12 is 2p, and p is the pole pair number of the motor 100. The position and depth of the second auxiliary grooves 12 can be changed by adjusting the parameters La and Ra.

[0095] Specifically, θ should be in the range of [ t p / 5, t p / 4], Lb should be in the range of 2mm~3mm, Wb should be in the range of 0.3mm~0.5mm, R r -(L a -R a ) should be in the range of 0.2mm~0.8mm.

[0096] In the above embodiment, the air gap permeance function is adjusted, and then the sinusoidal degree of the air gap magnetic flux density is optimized, which is beneficial to reduce the cogging torque and the radial electromagnetic force, and then reduce the vibration noise of the motor 100, and will not affect the output performance of the motor 100.

[0097] The other constitution and operation of the food processor and the motor 100 according to the embodiments of the utility model are known to those skilled in the art, and will not be described in detail here.

[0098] In the description of the utility model, it is necessary to explain, unless another explicit provision and limitation, the term "installation", "link", "connection" should do the broad sense understanding, for example, can be fixed connection, also can be detachable connection, or integrally connected;Can be mechanical connection, also can be electrical connection;Can be directly connected, also can pass through the indirect connection of intermediate medium, can be two elements inside the communication.For ordinary skilled in the art, the specific meaning of the above terms in the utility model can be understood according to the specific circumstances.

[0099] In the description of the present specification, the description of the terms "embodiment", "specific embodiment", "example" and the like means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are contained in at least one embodiment or example of the utility model. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0100] Although the embodiments of the utility model have been shown and described, those skilled in the art can understand that various changes, modifications, replacements and variations can be made to these embodiments without departing from the principles and purposes of the utility model, and the scope of the utility model is defined by the claims and their equivalents.

Claims

1. A rotor core characterized by, The outer circumferential surface of the rotor core is provided with a first auxiliary groove, two first auxiliary grooves are provided corresponding to the same magnetic pole and the two first auxiliary grooves are symmetrically arranged about the center line of the magnetic pole, the first auxiliary groove extends along the axial direction of the rotor core, and the cross section of the groove wall surface of the first auxiliary groove perpendicular to the axis of the rotor core is a part of an ellipse, the center of the ellipse and the line connecting the axis of the rotor core are auxiliary lines, the long axis of the ellipse is perpendicular to the auxiliary line, and the short axis of the ellipse coincides with the auxiliary line.

2. The rotor core according to claim 1, characterized by The auxiliary line and the middle line corresponding to the magnetic pole form an angle θ, θ is greater than or equal to τ p / 5 and less than or equal to τ p / 4, wherein τ p is the pole pitch.

3. The rotor core according to claim 2, characterized by The length of the long semi-axis of the ellipse is greater than or equal to 2 mm and less than or equal to 3 mm.

4. The rotor core according to claim 3, characterized by The length of the short semi-axis of the ellipse is greater than or equal to 0.3 mm and less than or equal to 0.5 mm.

5. The rotor core according to claim 1, characterized by The rotor core is provided with a mounting groove for mounting a permanent magnet, the mounting groove extends perpendicular to the center line of the magnetic pole, and both ends of the mounting groove are respectively provided with air grooves, The distance between one end of the first auxiliary groove close to the center line of the magnetic pole and the mounting groove is L1, the distance between the first auxiliary groove and the end of the mounting groove is L2, L1 is greater than L2; and / or, The distance between the first auxiliary groove and the air groove increases in the direction away from the center line of the magnetic pole.

6. The rotor core according to any one of claims 1 to 5, characterized by The outer circumferential surface of the rotor core is provided with a second auxiliary groove, the second auxiliary groove extends along the axial direction of the rotor core, one second auxiliary groove is provided corresponding to one magnetic pole, and the second auxiliary groove is symmetric about the center line of the corresponding magnetic pole.

7. The rotor core according to claim 6, characterized by The cross section of the groove wall surface of the second auxiliary groove perpendicular to the axis of the rotor core is a part of a circle.

8. The rotor core according to claim 7, characterized by The distance between the center of the circle and the axis of the rotor core is La, the radius of the circle is Ra, and the radius of the outer circumferential surface of the rotor core is Rr, wherein, Rr-(La-Ra) is greater than or equal to 0.2 mm and less than or equal to 0.8 mm.

9. A rotor assembly characterized by, A rotor core according to any one of claims 1-8 is provided with an axially extending mounting groove, and a permanent magnet is mounted in the mounting groove.

10. An electric machine characterized by A rotor assembly according to claim 9 is provided.

11. The electric machine of claim 10, wherein, The motor is a 10-pole 12-slot motor.

12. A food processor, characterized in that, A motor according to claim 10 or 11 is provided.

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