Rotor assembly, external rotor motor and household appliance

Abstract

The utility model discloses a rotor assembly, an external rotor motor and a household electrical appliance, and belongs to the technical field of motors. The rotor assembly comprises an annular first yoke part, a plurality of permanent magnets and an annular second yoke part, and the permanent magnets are arranged on the inner circumferential wall of the first yoke part at intervals in the circumferential direction of the first yoke part; the second yoke part and the first yoke part are coaxially arranged, and the second yoke part is arranged on the peripheral wall of the first yoke part in a surrounding mode; at least one end of the second yoke part protrudes out of the first yoke part in the axial direction of the rotor assembly. Different magnetic gathering effects are generated through the first yoke part and the second yoke part, so that the distribution and the path of magnetic flux are optimized, the generation of harmonic waves is reduced, the reduction of the harmonic waves effectively inhibits the generation of electromagnetic oscillation, the high-frequency output is reduced, the generation of electromagnetic noise of the motor is reduced, and the motor can be kept quiet during operation, therefore, the service life of the motor is prolonged, and the service life of the motor is prolonged. When the method is applied to the household electrical appliance, user experience can be improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to motor technical field, especially rotor assembly, outer rotor motor and household appliance. BACKGROUND

[0002] In the related art, in order to improve the power density of the motor, the conventional rotor structure generally designs the permanent magnet into the tile type structure of the concentricity of inner and outer circular arcs.However, the magnetic field waveform generated by the permanent magnet of this structure is close to the saddle shape.The saddle-shaped magnetic field waveform not only contains the main fundamental component, but also generates a large number of harmonic components, especially the content of high-order harmonics such as three, five and seven is relatively high.The harmonic components will interact with the excitation magnetic field excited by the high-frequency carrier current generated in the motor controller, generate high-frequency electromagnetic oscillation in the motor, thereby form high-frequency output, and further increase the electromagnetic noise of the motor. SUMMARY

[0003] The utility model at least solves one of the technical problems in the prior art. To this end, the utility model provides a rotor assembly, which can reduce the generation of harmonics, thereby inhibiting the formation of high-frequency output, and further reducing the electromagnetic noise of the motor.

[0004] The utility model further provides an outer rotor motor and a household appliance comprising the above rotor assembly.

[0005] According to the rotor assembly of the first aspect of the utility model, the rotor assembly is applied to an outer rotor motor, which comprises a first yoke portion in the form of a ring, a plurality of permanent magnets and a second yoke portion in the form of a ring, the plurality of permanent magnets are arranged on the inner circumferential wall of the first yoke portion in a circumferential direction of the first yoke portion, the second yoke portion is coaxially arranged with the first yoke portion, and the second yoke portion is arranged around the outer circumferential wall of the first yoke portion, wherein at least one end of the second yoke portion protrudes from the first yoke portion in the axial direction of the rotor assembly.

[0006] The rotor assembly according to the utility model embodiment has at least the following beneficial effects:

[0007] In the rotor assembly of the utility model embodiment, the double-layer yoke structure of the first yoke portion and the second yoke portion is provided, wherein the plurality of permanent magnets are arranged on the inner circumferential wall of the first yoke portion in a circumferential direction of the first yoke portion, the second yoke portion is arranged around the outer circumferential wall of the first yoke portion, and at least one end of the second yoke portion protrudes from the first yoke portion in the axial direction of the rotor assembly, therefore, the first yoke portion and the second yoke portion generate different magnetic concentration effects, thereby optimizing the distribution and path of the magnetic flux, reducing the generation of harmonics, effectively inhibiting the generation of electromagnetic oscillation, reducing the high-frequency output, reducing the generation of electromagnetic noise of the motor, and enabling the motor to run quietly, therefore, when applied to a household appliance, the user's use experience can be improved.

[0008] According to some embodiments of the present application, the rotor assembly further comprises a housing and a rotating shaft, the housing comprises an end plate part and an annular part, the end plate part is fixedly connected with the rotating shaft, the annular part is arranged along the circumference of the rotating shaft and is connected with the outer circumferential edge of the end plate part, and the second yoke part is configured as a partial structure of the annular part.

[0009] According to some embodiments of the present application, the rotor assembly further comprises a housing and a rotating shaft, the housing comprises an end plate part and an annular part, the end plate part is fixedly connected with the rotating shaft, the annular part is arranged along the circumference of the rotating shaft and is connected with the outer circumferential edge of the end plate part, and the second yoke part is connected with the inner side of the annular part.

[0010] According to some embodiments of the present application, one end of the annular part away from the end plate part is provided with a bending part, and the bending part extends outward along the radial direction of the annular part.

[0011] According to some embodiments of the present application, along the radial direction of the rotor assembly, the minimum thickness of the first yoke part is h, the sum of the minimum thickness of the first yoke part and the minimum thickness of the second yoke part is H, and 0

[0012] According to some embodiments of the present application, along the axial direction of the rotor assembly, the minimum width of the first yoke part is W1, the minimum width of the second yoke part is W2, and W2-W1≥2mm.

[0013] According to some embodiments of the present application, the rotor assembly further comprises a support, the support comprises a connecting ring and a plurality of stop parts, the connecting ring is arranged along the circumference of the rotor assembly, the plurality of stop parts are arranged on the inner side of the connecting ring along the circumference of the connecting ring, the permanent magnet is mounted between two adjacent stop parts, along the axial direction of the rotor assembly, one end of the second yoke part protrudes from the first yoke part, the connecting ring is located between the part of the second yoke part protruding from the first yoke part and the permanent magnet, and is connected with the first yoke part.

[0014] According to some embodiments of the utility model, the rotor assembly further includes two supports, the two supports are arranged at intervals along the axial direction of the rotor assembly, the support includes a connecting ring and a plurality of stop portions, the connecting ring is arranged along the circumferential direction of the rotor assembly, the plurality of stop portions are arranged at intervals on the inner side of the connecting ring along the circumferential direction of the connecting ring, the permanent magnet is mounted between two adjacent stop portions in the circumferential direction of the connecting ring, the stop portions of the two supports are arranged correspondingly, along the axial direction of the rotor assembly, the two ends of the second yoke portion protrude from the first yoke portion, the first yoke portion is mounted in the avoiding groove, and the connecting ring is located between the part of the second yoke portion protruding from the first yoke portion and the permanent magnet.

[0015] According to some embodiments of the utility model, the two connecting rings are respectively provided with a plurality of limiting portions, the plurality of limiting portions are arranged at intervals along the circumferential direction of the connecting ring and correspond to the plurality of permanent magnets one by one, the limiting portion is arranged at one end of the connecting ring away from the other support, the limiting portion in one of the supports abuts one end of the permanent magnet along the axial direction of the rotor assembly, and the limiting portion in the other support abuts the other end of the permanent magnet along the axial direction of the rotor assembly.

[0016] According to some embodiments of the utility model, one of the two supports is a first support, and the other is a second support, the limiting portion of the first support is configured as a baffle protruding from the end face of the connecting ring away from the second support, the baffle is bent towards the inner side, the limiting portion of the second support is configured as a step, the two ends of the step are connected to two adjacent stop portions in the second support respectively, the step is arranged on the side of the second support away from the first support, and the step cooperates with the baffle to limit the permanent magnet.

[0017] According to some embodiments of the utility model, the rotor assembly further includes a shell and a rubber ring, the shell includes an end plate portion and an annular portion, the annular portion is connected to the outer circumferential edge of the end plate portion and defines a containing groove with the end plate portion, the first support and the second support are arranged in the containing groove, the second support is located on the side close to the end plate portion, the step protrudes a convex ring towards the side of the end plate portion, the convex ring is arranged along the circumferential direction of the rotor assembly, the rubber ring is arranged around the convex ring, and the rubber ring abuts between the step and the end plate portion.

[0018] According to some embodiments of the utility model, the rotor assembly further includes a shell and a plastic package, the shell includes an end plate part and an annular part, the annular part is arranged along the circumference of the rotor assembly and is connected to the outer circumferential edge of the end plate part, the annular part and the end plate part define a containing groove, the first yoke part and the plurality of permanent magnets are connected through the plastic package, the plastic package at least covers two ends of the first yoke part along the axial direction of the rotor assembly and two ends of the permanent magnets along the axial direction of the rotor assembly, so that the first yoke part and the permanent magnets form an integrated structure, the integrated structure is installed in the containing groove, and the second yoke part is arranged on the outer side of the plastic package.

[0019] Alternatively, the first yoke part, the second yoke part and the plurality of permanent magnets are connected through the plastic package, the plastic package at least covers two ends of the first yoke part along the axial direction of the rotor assembly, two ends of the second yoke part along the axial direction of the rotor assembly and two ends of the permanent magnets along the axial direction of the rotor assembly, so that the first yoke part, the second yoke part and the permanent magnets form an integrated structure, and the integrated structure is installed in the containing groove.

[0020] According to the outer rotor motor of the second aspect embodiment of the utility model, the stator is arranged in the rotor assembly.

[0021] According to the outer rotor motor of the utility model embodiment, at least the following beneficial effects are achieved:

[0022] The outer rotor motor adopts the rotor assembly of the first aspect embodiment, different magnetic concentration effects are realized through the first yoke part and the second yoke part, the distribution and path of the magnetic flux are optimized, the generation of harmonics is reduced, the generation of electromagnetic oscillation is effectively inhibited due to the reduction of harmonics, high-frequency output is reduced, the generation of electromagnetic noise of the outer rotor motor is reduced, the outer rotor motor can be kept quiet during operation, therefore, when applied to household appliances, the use experience of users can be improved.

[0023] According to the household appliance of the third aspect embodiment of the utility model, the outer rotor motor of the second aspect embodiment is included.

[0024] According to the household appliance of the utility model embodiment, at least the following beneficial effects are achieved:

[0025] The household appliance adopts the outer rotor motor of the second aspect embodiment, different magnetic aggregation effects are realized through the first yoke part and the second yoke part, so that the distribution and path of the magnetic flux are optimized, the generation of harmonics is reduced, and then the generation of electromagnetic noise of the outer rotor motor is reduced, so that the outer rotor motor can be kept quiet when running, when the outer rotor motor is applied to the household appliance, the discomfort caused by noise to the user is reduced, a more quiet use environment is provided for the user, and the use experience of the user is improved.

[0026] Additional aspects and advantages of the present application will be given in part in the following description, and will become apparent from the following description, or will be learned by practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0027] The present application will be further described below in conjunction with the drawings and embodiments, wherein:

[0028] Figure 1 is a top view of the rotor assembly of an embodiment of the present application;

[0029] Figure 2 is Figure 1 is a sectional view in the direction of A-A;

[0030] Figure 3 is Figure 2 is an enlarged view of B;

[0031] Figure 4 is a partial sectional view of the rotor assembly of another embodiment of the present application;

[0032] Figure 5 is an assembly view of the first yoke part and the second yoke part of an embodiment of the present application;

[0033] Figure 6 is an assembly view of the first yoke part and the second yoke part of another embodiment of the present application;

[0034] Figure 7 is an assembly view of the first yoke part and the second yoke part of another embodiment of the present application;

[0035] Figure 8 is a sectional view of the rotor assembly of another embodiment of the present application;

[0036] Figure 9 is Figure 8 is an enlarged view of C;

[0037] Figure 10 is an assembly view of the two supports of an embodiment of the present application;

[0038] Figure 11 is a structural schematic view of the rotor assembly of an embodiment of the present application;

[0039] Figure 12 An exploded view of the rotor assembly of the embodiment of the present application;

[0040] Figure 13 An assembly schematic view of the two brackets of another embodiment of the present application;

[0041] Figure 14 An exploded view of the rotor assembly of another embodiment of the present application;

[0042] Figure 15 An exploded view of the rotor assembly of another embodiment of the present application;

[0043] Figure 16 A waveform diagram of the rotor assembly of the embodiment of the present application rotating a full circle;

[0044] Figure 17 A single-tooth counter EMF FFT decomposition diagram of the existing rotor assembly and the rotor assembly of the embodiment of the present application;

[0045] Figure 18 A near-field noise test diagram of the front shaft end of the external rotor motor when the rotor assembly of the embodiment of the present application is applied;

[0046] Figure 19 A near-field noise test diagram of the rear shaft end of the external rotor motor when the rotor assembly of the embodiment of the present application is applied.

[0047] Reference signs:

[0048] Rotor assembly 1000;

[0049] First yoke portion 100; permanent magnet 200; second yoke portion 300; housing 400; end plate portion 410; opening 411; annular portion 420; bent portion 421; accommodating groove 430; rotating shaft 500; bracket 600; connecting ring 601; stop portion 610; protruding portion 611; mounting groove 620; avoiding groove 630; first bracket 640; limiting portion 641; baffle 642; second bracket 650; step 651; protruding ring 652; rubber ring 700; plastic-coated body 800. DETAILED DESCRIPTION

[0050] The embodiments of the present application will be described in detail below, examples of which are shown in the drawings, wherein the same or similar reference signs represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are only used to explain the present application, and cannot be understood as a limitation of the present application.

[0051] In the description of the utility model, it needs to be understood that, if the direction description, such as the direction or position relation indicated by up, down etc. is based on the direction or position relation shown in the drawing, it is only for the convenience of describing the utility model and simplifying the description, and it is not indicated or implied that the device or element indicated must have a particular direction, a particular direction structure and operation, therefore it can not be understood as the limitation of the utility model.

[0052] In the description of the utility model, if the first, second is described for the purpose of distinguishing technical features, it can not be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features or implicitly indicating the sequence of indicated technical features.

[0053] In the description of the utility model, unless otherwise explicitly limited, the words such as setting, installing and connecting should be understood in a broad sense, and the skilled in the art can reasonably determine the specific meaning of the above words in the utility model according to the specific content of the technical scheme.

[0054] The traditional rotor structure generally adopts the setting mode that the permanent magnet is directly attached to the inner arc surface of the magnetic yoke, wherein, in order to improve the power density of the motor, the permanent magnet is usually designed into a tile type structure with concentric inner and outer arc surfaces. However, the magnetic field waveform generated by the permanent magnet with such structure is close to a saddle shape. The saddle-shaped magnetic field waveform not only contains the main fundamental component, but also generates a large amount of harmonic components, especially the content of three, five and seven times of high-order harmonics is relatively high. The magnetic field with these harmonic contents excited by the permanent magnet will interact with the excitation magnetic field excited by the high-frequency carrier current in the motor controller, resulting in high-frequency electromagnetic oscillation in the motor, thereby forming high-frequency output, and further increasing the electromagnetic noise of the motor.

[0055] Some rotor structures reduce the generation of harmonics by changing the shape of the magnetic tile (such as changing the traditional tile-shaped magnetic tile into a bread-shaped magnetic tile or an inner and outer eccentric arc magnetic tile). However, such structural improvement will cause the thickness of the ferrite magnetic yoke on both sides to be thinned, thereby reducing the use amount of ferrite. In order to maintain the same power output as the tile-shaped ferrite, the number of turns of the coil must be increased, thereby increasing the manufacturing cost of the rotor structure.

[0056] Therefore, some embodiments of the utility model provide a rotor assembly 1000 suitable for a motor (not shown in the figure), specifically, the motor is an outer rotor motor, the rotor assembly 1000 is an outer rotor and can rotate around the rotation axis, and specific reference is made to the rotor assembly 1000 shown in the figure. Figures 1 to 15

[0057] Referring to Figure 1 ​As shown in the utility model embodiment, the rotor assembly 1000 comprises a plurality of permanent magnets 200, and the plurality of permanent magnets 200 are arranged at intervals in the circumferential direction of the rotation shaft axis. Figure 2 And Figure 3 It can be understood that, in the embodiment, the rotor assembly 1000 further comprises a first yoke part 100 and a second yoke part 300, both of which are annular, and the first yoke part 100 and the second yoke part 300 are coaxially arranged, specifically, both of them are arranged in the circumferential direction of the rotation shaft axis.

[0058] Referring to Figure 2 And Figure 3 As shown in the utility model embodiment, the first yoke part 100 is arranged between the second yoke part 300 and the permanent magnet 200, wherein the plurality of permanent magnets 200 are arranged at intervals in the circumferential direction of the first yoke part 100, and the permanent magnet 200 is attached to the inner circumferential wall of the first yoke part 100. The second yoke part 300 is arranged in extension in the circumferential direction of the first yoke part 100 and is located on the outer side of the second yoke part 300. The inner circumferential wall of the second yoke part 300 is attached to the outer circumferential wall of the first yoke part 100.

[0059] It should be noted that, in the utility model embodiment, the connection mode between the permanent magnet 200, the first yoke part 100 and the second yoke part 300 can be various, and the embodiment does not limit this. In one example, the permanent magnet 200 is bonded to the inner circumferential wall of the first yoke part 100; in another example, the permanent magnet 200 is indirectly connected to the first yoke part 100 through an intermediate part. In one example, the second yoke part 300 is bonded to the first yoke part 100; in another example, the second yoke part 300 is interference fit with the first yoke part 100.

[0060] Referring to Figure 2 And Figure 3 As shown in the utility model embodiment, the rotor assembly 1000 further comprises a housing 400 and a rotation shaft 500, wherein the housing 400 comprises an end plate part 410 and an annular part 420, the end plate part 410 is a circular plate part with the rotation shaft axis as the central axis, an opening 411 for the rotation shaft 500 to pass through is arranged at the center position, and the rotation shaft 500 is fixedly connected with the end plate part 410. The annular part 420 is arranged in the circumferential direction of the rotation shaft 500, thereby forming a circular ring-shaped plate part, and the annular part 420 is connected with the outer circumferential wall of the end plate part 410 and forms a containing groove 430. Specifically, the annular part 420 and the end plate part 410 can be integrally stamped and formed, or can be a split structure, and the embodiment does not limit this.

[0061] It can be understood that, in the utility model embodiment, the first yoke part 100 and the second yoke part 300 form a double-layer magnetic yoke structure. Based on this, referring to Figure 3As shown, in the embodiment of the utility model, the second yoke part 300 is a part of the shell 400, and the permanent magnet 200 and the first yoke part 100 are arranged in the accommodating groove 430. Specifically, in the embodiment, the second yoke part 300 is configured as a part of structure of the annular part 420, at least part of the annular part 420 is made of magnetic conductive material, so that the second yoke part 300 is formed on the annular part 420. It should be noted that in the embodiment, the annular part 420 can only partially constitute the second yoke part 300, or can completely serve as the second yoke part 300.

[0062] Referring to Figure 4 As shown, in another example, the permanent magnet 200, the first yoke part 100 and the second yoke part 300 are arranged in the accommodating groove 430, and the second yoke part 300 is connected to the inner side of the annular part 420, wherein the outer peripheral wall of the second yoke part 300 is connected with the inner peripheral wall of the annular part 420. It should be noted that along the axial direction of the rotation shaft 500, the width of the second yoke part 300 is less than or equal to the width of the annular part 420.

[0063] For the convenience of description, in the following description, the second yoke part 300 is formed in the shell 400 as an example. In order to optimize the distribution and path of magnetic flux through the double-layer magnetic yoke structure formed by the first yoke part 100 and the second yoke part 300, referring to Figure 3 As shown, in the embodiment of the utility model, along the axial direction of the rotor assembly 1000, at least one end of the second yoke part 300 protrudes from the first yoke part 100. It can be understood that, for example, Figure 3 The embodiment can be that the upper end of the second yoke part 300 is higher than the upper end of the first yoke part 100, or the lower end of the second yoke part 300 is lower than the lower end of the first yoke part 100, so as to form a height difference of at least one end therebetween, and thus the first yoke part 100 and the second yoke part 300 achieve different magnetic concentration effects, reducing the generation of harmonics.

[0064] It can be understood that, by optimizing the distribution and path of magnetic flux, the embodiment of the utility model reduces the generation of harmonics, the reduction of harmonics effectively suppresses the generation of electromagnetic oscillation, reduces high-frequency output, reduces the generation of electromagnetic noise of the outer rotor motor, and enables the outer rotor motor to run quietly, so that when applied to household appliances, the user's use experience can be improved.

[0065] Referring to Figure 5 As shown, in one example, the upper end of the second yoke part 300 protrudes from the upper end of the first yoke part 100 along the axial direction of the rotation shaft 500, and the lower end of the second yoke part 300 protrudes from the lower end of the first yoke part 100 along the axial direction of the rotation shaft 500. Referring to Figure 6As shown, in another example, the upper end of the second yoke portion 300 is flush with the upper end of the first yoke portion 100 in the axial direction of the rotation shaft 500, and the lower end of the second yoke portion 300 protrudes from the lower end of the first yoke portion 100 in the axial direction of the rotation shaft 500. Referring to Figure 7 As shown, in another example, the upper end of the second yoke portion 300 protrudes from the upper end of the first yoke portion 100 in the axial direction of the rotation shaft 500, and the lower end of the second yoke portion 300 is flush with the lower end of the first yoke portion 100 in the axial direction of the rotation shaft 500.

[0066] Referring to Figure 8 and Figure 9 As shown, in the embodiment of the utility model, the one end of annular portion 420 away from end plate portion 410 is equipped with bending portion 421, bending portion 421 extends to the outside along the radial direction of annular portion 420. Specifically, bending portion 421 is integrally formed on the outer wall of annular portion 420, and is bent away from the rotation shaft 500, thereby forming a flanging structure. In this embodiment, the extending direction of bending portion 421 can be the direction of the first yoke portion 100 towards the second yoke portion 300. It can be understood that the embodiment can strengthen the structural rigidity of the shell 400 by setting the bending portion 421, thereby improving the modal frequency of the shell 400, and reducing the frequency response amplitude, thereby effectively suppressing the vibration noise of the shell 400.

[0067] Referring to Figure 3 As shown, in the embodiment of the utility model, along the radial direction of the rotor assembly, the minimum thickness of the first yoke portion 100 is h, the sum of the minimum thickness of the first yoke portion 100 and the minimum thickness of the second yoke portion 300 is H, and it satisfies: 0

[0068] It can be understood that, in the case that the sum H of the minimum thickness of the first yoke portion 100 and the minimum thickness of the second yoke portion 300 is unchanged, when h / H is greater than 0.6, it means that the value of h is too large, that is, the minimum thickness of the first yoke portion 100 is too thick, and the minimum thickness of the second yoke portion 300 will be too thin, which not only causes the structural strength of the second yoke portion 300 to be too low, making it vulnerable to vibration and impact, but also weakens its magnetic aggregation performance, thereby reducing the effect of suppressing harmonics. Therefore, by reasonably designing the range of h / H, it can ensure that the second yoke portion 300 has sufficient structural strength, and at the same time, it can produce different magnetic aggregation effects from the first yoke portion 100, thereby effectively suppressing the generation of harmonics.

[0069] For the convenience of description, the following description is described by taking the second yoke part 300 connected to the inner side of the annular part 420 as an example. Referring to Figure 4 As shown in the embodiment of the utility model, along the axial direction of the rotor assembly 1000, the minimum width of the first yoke part 100 is W1, and the minimum width of the second yoke part 300 is W2, and it satisfies: W2-W1≥2mm. It can be understood that in the embodiment, the minimum width of the first yoke part 100 is less than the minimum width of the second yoke part 300, so there is a difference between them, for example: 2mm, 2.5mm, 4mm, etc. It should be noted that the minimum width of the second yoke part 300 is greater than the minimum width of the first yoke part 100, based on this, when one end of the second yoke part 300 is flush with one end of the first yoke part 100, the width of the protruding part at the other end of the second yoke part 300 is the difference between the minimum width of the first yoke part 100 and the minimum width of the second yoke part 300. When both ends of the second yoke part 300 protrude from the first yoke part 100, the sum of the widths of the two protruding parts is the difference between the minimum width of the first yoke part 100 and the minimum width of the second yoke part 300.

[0070] It can be understood that when W2-W1 is less than 2mm, the width of the protruding part of the second yoke part 300 is too small, making it difficult for the second yoke part 300 to form a different magnetic concentration effect from the first yoke part 100, thereby making it difficult for the magnetic field to concentrate, making it difficult for the rotor assembly 1000 to reduce the generation of harmonics. Therefore, by reasonably designing the range of W2-W1, the different magnetic concentration effects of the first yoke part 100 and the second yoke part 300 can be further ensured, thereby optimizing the distribution and path of the magnetic flux and reducing the generation of harmonics.

[0071] Referring to Figure 10 As shown in the embodiment of the utility model, the rotor assembly 1000 further comprises a support 600 for supporting and fixing a plurality of permanent magnets 200, specifically, the support 600 comprises a connecting ring 601 and a stop part 610, wherein the connecting ring 601 is a ring structure, which is arranged along the circumferential direction of the rotor assembly 1000, based on this, the connecting ring 601 can be arranged outside the plurality of permanent magnets 200, and the connecting ring 601 is arranged in the accommodating groove 430 and connected with the annular part 420. The inner circumferential wall of the connecting ring 601 is provided with a plurality of stop parts 610, and the stop parts 610 protrude towards the shaft 500. In the embodiment, a plurality of stop parts 610 are arranged at intervals along the circumferential direction of the support 600, based on this, an installation groove 620 can be defined between two adjacent stop parts 610.

[0072] Continuing to refer to Figure 10As shown, it can be understood that in the embodiment of the utility model, the shape and size of the installation groove 620 match the shape and size of the permanent magnet 200, and are suitable for the installation of the permanent magnet 200. The number of the installation groove 620 is the same as the number of the permanent magnet 200, and based on this, the plurality of permanent magnets 200 can be one-to-one corresponding installed in the plurality of installation grooves 620, when the permanent magnet 200 is installed in the installation groove 620, the permanent magnet 200 and the bracket 600 can be connected by adhesion, or can be connected by interference fit, and the embodiment does not limit this. In an example, along the axial direction of the rotating shaft 500, the bracket 600 is arranged at the middle part of the permanent magnet 200.

[0073] Referring to Figure 3 As shown, in the embodiment of the utility model, one end of the second yoke part 300 protrudes from the first yoke part 100, the connecting ring 601 is located between the part of the second yoke part 300 protruding from the first yoke part 100 and the permanent magnet 200, and is connected with the first yoke part 100.

[0074] Combined with Figure 1 And Figure 10 It can be understood that in the embodiment of the utility model, the end part of the stop part 610 towards the rotating shaft 500 is provided with a protruding part 611, the protruding part 611 extends along the end surface of the permanent magnet 200 and abuts against the end surface of the permanent magnet 200 towards the rotating shaft 500, and the bracket 600 abuts against the end surface of the permanent magnet 200 away from the rotating shaft 500, thereby limiting the movement of the permanent magnet 200 in the radial direction of the rotating shaft 500, ensuring that the permanent magnet 200 can be stably fixed on the bracket 600, and helping the first yoke part 100 to be closely arranged on the permanent magnet 200. Specifically, the end part of the stop part 610 is provided with two protruding parts 611 arranged away from each other, and the two protruding parts 611 protrude towards the two permanent magnets 200 located on both sides of the stop part 610 respectively, thereby limiting the two permanent magnets 200 respectively, and improving the compactness between the permanent magnets 200.

[0075] Referring to Figure 3 And Figure 12As shown in the utility model embodiment, the rotor assembly 1000 includes two brackets 600, and the two brackets 600 are arranged along the axial direction of the rotor assembly 1000, that is, the axial direction of the rotating shaft 500. The bracket 600 includes a connecting ring 601 and a plurality of stop portions 610. The connecting ring 601 is arranged along the circumferential direction of the rotor assembly 1000, and the plurality of stop portions 610 are arranged on the inner side of the connecting ring 601 along the circumferential direction of the connecting ring 601. The stop portions 610 of the two brackets 600 are correspondingly arranged and cooperatively define a mounting groove 620. It can be understood that the two stop portions 610 of the two brackets 600 are taken as an example for description, and the two adjacent limiting assemblies cooperatively define the mounting groove 620. When the permanent magnet 200 is installed in the mounting groove 620, the two stop portions 610 of one limiting assembly limit one side of the permanent magnet 200, and the two stop portions 610 of the other limiting assembly limit the other side of the permanent magnet 200.

[0076] Referring to Figure 3 and Figure 10 As shown in the utility model embodiment, along the axial direction of the rotor assembly 1000, the two ends of the second yoke portion 300 protrude from the first yoke portion 100. The two connecting rings 601 define an avoiding groove 630 therebetween. Specifically, the avoiding groove 630 is arranged along the circumferential direction of the first yoke portion 100, and thus the avoiding groove 630 can be in communication with all the mounting grooves 620. Based on this, the connecting ring 601 is located between the portion of the second yoke portion 300 protruding from the first yoke portion 100 and the permanent magnet 200. Specifically, when the first yoke portion 100 is installed in the avoiding groove 630, the first yoke portion 100 can be connected with the permanent magnet 200 in the mounting groove 620. It can be understood that along the axial direction of the rotating shaft 500, the sum of the widths of the two brackets 600 is less than the width of the permanent magnet 200. Therefore, at least part of the permanent magnet 200 is exposed between the two brackets 600, and the first yoke portion 100 installed in the avoiding groove 630 can be attached to the exposed part of the permanent magnet 200.

[0077] In combination with Figure 3 It can be understood that in the utility model embodiment, when the first yoke portion 100 is installed in the avoiding groove 630, along the radial direction of the rotating shaft 500, the first yoke portion 100 is flush with the two brackets 600. Based on this, the bracket 600 and the first yoke portion 100 can be attached to the inner circumferential wall of the annular portion 420 together. This not only ensures that the relative position between the permanent magnet 200 installed on the bracket 600 and the first yoke portion 100 and the second yoke portion 300 is stable and unchangeable, but also enables one end of the first yoke portion 100 to be attached to the permanent magnet 200 and the other end to be attached to the second yoke portion 300.

[0078] Referring to Figure 12As shown in the utility model embodiment, the two supports 600 are identical in structure and are arranged in axial symmetry. Specifically, the two supports 600 are respectively provided with a plurality of limiting portions 641, and the number of the limiting portions 641 is identical to the number of the mounting grooves 620. The plurality of limiting portions 641 are arranged in a circumferential direction of the support 600 at intervals and are arranged in one-to-one correspondence with the plurality of mounting grooves 620. In combination with Figure 10 It can be understood that, in the embodiment, the limiting portion 641 is protruded from the surface of the support 600 in the axial direction of the rotating shaft 500, and the limiting portion 641 is protruded from the surface of the support 600 in the direction of the second yoke portion 300 towards the first yoke portion 100, i.e. towards the rotating shaft 500.

[0079] Referring to Figure 3 and Figure 10 As shown in the utility model embodiment, the limiting portion 641 is arranged at one end of the connecting ring 601 away from the other support 600. Specifically, the limiting portion 641 of the support 600 located on the upper side is arranged at the upper end of the support 600 and protrudes towards the upper side; on the contrary, the limiting portion 641 of the support 600 located on the lower side is arranged at the lower end of the support 600 and protrudes towards the lower side. It can be understood that, in the embodiment, the distance between the two corresponding limiting portions 641 of the two supports 600 is suitable for accommodating the permanent magnet 200.

[0080] Based on this, referring to Figure 3 As shown in the utility model embodiment, when the permanent magnet 200 is installed in the mounting groove 620, the two corresponding limiting portions 641 of the two supports 600 can abut against the upper side and the lower side of the permanent magnet 200 respectively, thereby limiting the movement of the permanent magnet 200 in the axial direction of the rotating shaft 500, further ensuring that the permanent magnet 200 can be stably fixed to the support 600, which is helpful for the first yoke portion 100 to be arranged closely to the permanent magnet 200.

[0081] Referring to Figure 13 and Figure 14 As shown in the utility model embodiment, the two supports 600 are different in structure. Specifically, one of the two supports 600 is a first support 640, and the other is a second support 650. In one example, the first support 640 is Figure 13 one located on the upper side, and the second support 650 is one located on the lower side.

[0082] It can be understood that, referring to Figure 13As shown, in this embodiment of the invention, the stop portion 610 of the first bracket 640 and the stop portion 610 of the second bracket 650 are correspondingly arranged to define a plurality of mounting slots 620. A baffle 642 protrudes from the upper surface of the first bracket 640 and is bent toward the rotating shaft 500. A step 651 is provided on the lower surface of the second bracket 650. Specifically, two adjacent stop portions 610 in the second bracket 650 are connected to form a step 651, which protrudes from the surface of the second bracket 650 toward the rotating shaft 500. In this embodiment, a plurality of steps 651 are provided, spaced apart circumferentially along the rotor assembly 1000, and the number of steps 651 is the same as the number of mounting slots 620.

[0083] Combination Figure 9 It is understood that in this embodiment of the present invention, the baffle 642 can abut against the upper side of the permanent magnet 200, and the step 651 abuts against the lower side of the permanent magnet 200, thereby restricting the movement of the permanent magnet 200 in the axial direction of the rotating shaft 500, further ensuring that the permanent magnet 200 can be stably fixed to the bracket 600, which helps the first yoke 100 to be tightly attached to the permanent magnet 200.

[0084] During assembly, after the permanent magnet 200 is installed, the first bracket 640 and the second bracket 650 can be placed into the receiving groove 430. To ensure that the first bracket 640 and the second bracket 650 do not directly contact and collide with the end plate portion 410 due to vibration during operation, refer to... Figure 9 and Figure 13 As shown in this embodiment of the present invention, along the direction from the annular portion 420 toward the end plate portion 410, the first bracket 640 and the second bracket 650 are sequentially arranged in the receiving groove 430. It can be understood that the second bracket 650 is located on the side closer to the end plate portion 410. Based on this, a protruding ring 652 is provided on the side of the step 651 facing the end plate portion 410. The protruding ring 652 protrudes from the lower surface of the step 651 and is arranged circumferentially along the axis of rotation 500.

[0085] Reference Figure 14 As shown, in this embodiment of the present invention, the rotor assembly 1000 further includes a rubber ring 700, which surrounds the convex ring 652, thereby allowing it to be fitted onto the outer periphery of the convex ring 652. Based on this, combined with Figure 9 It is understood that when the second bracket 650 is installed in the receiving groove 430, the upper end of the rubber ring 700 abuts against the step 651, and the lower side of the rubber ring 700 abuts against the end plate portion 410. The rubber ring 700 has the function of absorbing vibration, thereby reducing the vibration noise of the rotor assembly 1000.

[0086] Reference Figure 15As shown, in an example, the rotor assembly 1000 further comprises a plastic package 800, the first yoke 100 and the plurality of permanent magnets 200 are connected through the plastic package 800, the plastic package 800 covers at least a part of the first yoke 100 and at least a part of the permanent magnets 200, so that the first yoke 100 and the permanent magnets 200 form an integrated structure. Specifically, the plastic package 800 covers at least two ends of the first yoke 100 along the axial direction of the rotor assembly 1000 and at least two ends of the permanent magnets 200 along the axial direction of the rotor assembly 1000. It can be understood that, by using the integrated plastic package, the first yoke 100 and the plurality of permanent magnets 200 form an integrated structure, realizing the fixed connection of the first yoke 100 and the plurality of permanent magnets 200.

[0087] Compared with the bonding mode, the plastic package mode effectively enhances the connection strength of the first yoke 100 and the permanent magnets 200, and the plastic package 800 has a fixing and limiting effect on the permanent magnets 200, reducing the risk of dislocation of the permanent magnets 200, thereby improving the reliability of the rotor assembly 1000. In the embodiment, the second yoke 300 is arranged on the outer side of the plastic package 800.

[0088] In another example, the first yoke 100, the second yoke 300 and the plurality of permanent magnets 200 are connected through the plastic package 800, the plastic package 800 covers at least a part of the first yoke 100, at least a part of the second yoke 300 and at least a part of the permanent magnets 200, so that the first yoke 100 and the permanent magnets 200 form an integrated structure. Specifically, the plastic package 800 covers at least two ends of the first yoke 100 along the axial direction of the rotor assembly 1000, at least two ends of the second yoke 300 along the axial direction of the rotor assembly 1000 and at least two ends of the permanent magnets 200 along the axial direction of the rotor assembly 1000. It can be understood that, by using the integrated plastic package, the first yoke 100, the second yoke 300 and the plurality of permanent magnets 200 form an integrated structure, realizing the fixed connection of the first yoke 100, the second yoke 300 and the plurality of permanent magnets 200.

[0089] Compared with the bonding mode, the plastic package mode effectively enhances the connection strength of the first yoke 100, the second yoke 300 and the permanent magnets 200, and the plastic package 800 has a fixing and limiting effect on the permanent magnets 200, reducing the risk of dislocation of the permanent magnets 200, thereby improving the reliability of the rotor assembly 1000.

[0090] In order to realize that the rotor assembly 1000 of the embodiment of the utility model can reduce the noise level by inhibiting the generation of harmonics, the inventor measures the single-tooth back EMF of the rotor assembly 1000. It needs to be explained that the single-tooth back EMF is the potential waveform generated by the coil on the single tooth when the rotor rotates through the coil at each magnetic pole. Referring to Figure 16As shown, the waveform corresponding to the complete rotation (360°) of the rotor assembly 1000 is shown. In order to reflect the harmonic condition of the magnetic circuit, the back EMF waveform needs to be subjected to a full-cycle fast Fourier transform (FFT decomposition).

[0091] Referring to Figure 17 As shown, the single-tooth back EMF FFT decomposition diagrams of the existing rotor assembly 1000 and the rotor assembly 1000 in the embodiment of the utility model are shown, wherein the solid line represents the decomposition result of the existing rotor assembly 1000, and the dotted line represents the decomposition of the rotor assembly 1000 in the embodiment of the utility model. It should be noted that only the decomposition results of the odd times (≥3) of the 5th order (5 pairs of poles are used in this example) are shown, and the normalization is performed according to the 5th order to facilitate comparative analysis.

[0092] It can be understood that, in the case of the same magnetic yoke structure, magnetic yoke thickness and stator tooth slot design, the rotor assembly 1000 of the embodiment obviously realizes the suppression of 15 times of the rotating frequency content, thereby effectively reducing the carrier noise. It should be noted that the thickness of the magnetic yoke in the rotor assembly 1000 of the embodiment refers to the sum of the thicknesses of the first yoke portion 100 and the second yoke portion 300.

[0093] The improvement of the noise can be seen from Figure 18 and Figure 19 As shown, the near-field noise of the front shaft end and the rear shaft end of the outer rotor motor is tested respectively, thereby directly verifying the effect of noise improvement. Among them, the dark column represents the noise level of the existing rotor assembly 1000, and the light column represents the noise level of the rotor assembly 1000 of the embodiment. Obviously, in the speed range of 400 RPM (revolutions per minute) to 1200 RPM (revolutions per minute), the noise level of the rotor assembly 1000 of the embodiment of the utility model is obviously lower than that of the existing rotor assembly 1000.

[0094] The embodiment of the utility model further proposes an outer rotor motor, which comprises a stator (not shown in the figure) and the rotor assembly 1000 of the above embodiment, and the stator is rotatably arranged in the rotor assembly 1000. Specifically, a plurality of permanent magnets 200 are arranged around the stator, the rotor assembly 1000 and the stator are rotatably connected, and the rotor assembly 1000 can rotate relative to the stator.

[0095] It can be understood that the outer rotor motor of the embodiment of the utility model adopts the rotor assembly 1000 of the above embodiment, realizes different magnetic aggregation effects through the first yoke portion 100 and the second yoke portion 300, thereby optimizing the distribution and path of the magnetic flux, reducing the generation of harmonics, effectively suppressing the generation of electromagnetic oscillation, reducing the high-frequency output, reducing the generation of electromagnetic noise of the outer rotor motor, and enabling the outer rotor motor to run quietly. Therefore, when applied to household appliances, the user's use experience can be improved.

[0096] Since the outer rotor motor adopts all the technical solutions of the rotor assembly 1000 of the above-mentioned embodiments, at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiments are achieved, and details are not repeated here.

[0097] The embodiment of the utility model further proposes a household appliance (not shown in the figure), comprising the outer rotor motor of the above-mentioned embodiment. Specifically, the household appliance can be an air conditioner, and can also be an electric fan and the like, and the embodiment does not limit this.

[0098] It can be understood that the household appliance of the embodiment of the utility model adopts the outer rotor motor of the above-mentioned embodiment, and different magnetic aggregation effects are realized through the first yoke part 100 and the second yoke part 300, so that the distribution and path of the magnetic flux are optimized, the generation of harmonics is reduced, and then the generation of electromagnetic noise of the outer rotor motor is reduced, so that the outer rotor motor can be kept quiet when running, and when the outer rotor motor is applied to the household appliance, the discomfort caused by noise to the user is reduced, a more quiet use environment is provided for the user, and then the use experience of the user is improved.

[0099] Since the household appliance adopts all the technical solutions of the outer rotor motor of the above-mentioned embodiments, at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiments are achieved, and details are not repeated here.

[0100] Of course, the utility model is not limited to the above-mentioned implementation manners, and those skilled in the art can also make equivalent modifications or replacements without departing from the spirit of the utility model, and these equivalent modifications or replacements are all included in the range defined by the claims of the present application.

Claims

1. A rotor assembly for use in an external rotor electric machine, characterized in that, The rotor assembly comprises: a first yoke in a ring shape; a plurality of permanent magnets arranged on an inner circumferential wall of the first yoke in a circumferential direction of the first yoke; a second yoke in a ring shape coaxially arranged with the first yoke, the second yoke being arranged around an outer circumferential wall of the first yoke; wherein at least one end of the second yoke protrudes from the first yoke in an axial direction of the rotor assembly.

2. The rotor assembly of claim 1, wherein The rotor assembly further comprises a housing and a rotating shaft, the housing comprises an end plate and a ring-shaped portion, the end plate is fixedly connected with the rotating shaft, the ring-shaped portion is arranged along a circumferential direction of the rotating shaft and connected to an outer circumferential edge of the end plate, and the second yoke is configured as part of the ring-shaped portion.

3. The rotor assembly of claim 1, wherein The rotor assembly further comprises a housing and a rotating shaft, the housing comprises an end plate and a ring-shaped portion, the end plate is fixedly connected with the rotating shaft, the ring-shaped portion is arranged along a circumferential direction of the rotating shaft and connected to an outer circumferential edge of the end plate, and the second yoke is connected to an inner side of the ring-shaped portion.

4. A rotor assembly according to claim 2 or 3, characterised in that An end of the ring-shaped portion away from the end plate is provided with a bending portion extending outward in a radial direction of the ring-shaped portion.

5. The rotor assembly of any one of claims 1 to 3, wherein, In a radial direction of the rotor assembly, a minimum thickness of the first yoke is h, and a sum of the minimum thickness of the first yoke and a minimum thickness of the second yoke is H, satisfying: 0 < h / H ≤ 0.

6.

6. The rotor assembly of claim 3, wherein In an axial direction of the rotor assembly, a minimum width of the first yoke is W1, and a minimum width of the second yoke is W2, satisfying: W2-W1 ≥ 2 mm.

7. The rotor assembly of claim 1, wherein The rotor assembly further comprises a support, the support comprises a connecting ring arranged in a circumferential direction of the rotor assembly and a plurality of stop portions arranged on an inner side of the connecting ring in a circumferential direction of the connecting ring, the permanent magnets are mounted between two adjacent stop portions, one end of the second yoke protrudes from the first yoke in an axial direction of the rotor assembly, the connecting ring is located between the permanent magnets and the part of the second yoke protruding from the first yoke, and the connecting ring is connected with the first yoke.

8. The rotor assembly of claim 1, wherein The rotor assembly further comprises two supports arranged in an axial direction of the rotor assembly, the support comprises a connecting ring arranged in a circumferential direction of the rotor assembly and a plurality of stop portions arranged on an inner side of the connecting ring in a circumferential direction of the connecting ring, the permanent magnets are mounted between two adjacent stop portions in the circumferential direction of the connecting ring, the stop portions of the two supports are correspondingly arranged, both ends of the second yoke protrude from the first yoke in the axial direction of the rotor assembly, a clearance is defined between the two connecting rings, the first yoke is mounted in the clearance, and the connecting ring is located between the permanent magnets and the part of the second yoke protruding from the first yoke.

9. The rotor assembly of claim 8, wherein, Two of the connecting rings are respectively provided with a plurality of limiting portions, the plurality of limiting portions are arranged at intervals along the circumferential direction of the connecting ring and correspond to the plurality of permanent magnets one by one, the limiting portion is arranged at one end of the connecting ring away from the other support, the limiting portion in one of the supports abuts one end of the permanent magnet along the axial direction of the rotor assembly, and the limiting portion in the other support abuts the other end of the permanent magnet along the axial direction of the rotor assembly.

10. The rotor assembly of claim 9, wherein, One of the two supports is a first support, and the other is a second support, the limiting portion of the first support is configured as a baffle protruding from the end face of the connecting ring away from the second support, the baffle is bent towards the inside, and the limiting portion of the second support is configured as a step, the two ends of the step are connected to the two adjacent stop portions in the second support, the step is arranged on the side of the second support away from the first support, and the step cooperates with the baffle to limit the permanent magnet.

11. The rotor assembly of claim 10, wherein, The rotor assembly further comprises a shell and a rubber ring, the shell comprises an end plate portion and an annular portion, the annular portion is connected to the outer circumferential edge of the end plate portion and defines a containing groove with the end plate portion, the first support and the second support are arranged in the containing groove, and the second support is located on the side close to the end plate portion, a convex ring protrudes from the side of the step towards the end plate portion, the convex ring is arranged along the circumferential direction of the rotor assembly, and the rubber ring is arranged around the convex ring and abuts between the step and the end plate portion.

12. The rotor assembly of claim 1, wherein The rotor assembly further comprises a shell and a plastic-coated body, the shell comprises an end plate portion and an annular portion, the annular portion is arranged along the circumferential direction of the rotor assembly and connected to the outer circumferential edge of the end plate portion, the annular portion and the end plate portion define a containing groove, the first yoke portion and the plurality of permanent magnets are connected through the plastic-coated body, the plastic-coated body at least covers the two ends of the first yoke portion along the axial direction of the rotor assembly and the two ends of the permanent magnet along the axial direction of the rotor assembly, so that the first yoke portion and the permanent magnet form an integrated structure, the integrated structure is installed in the containing groove, and the second yoke portion is arranged on the outer side of the plastic-coated body. Alternatively, the first yoke portion, the second yoke portion and the plurality of permanent magnets are connected through the plastic-coated body, the plastic-coated body at least covers the two ends of the first yoke portion along the axial direction of the rotor assembly, the two ends of the second yoke portion along the axial direction of the rotor assembly and the two ends of the permanent magnet along the axial direction of the rotor assembly, so that the first yoke portion, the second yoke portion and the permanent magnet form an integrated structure, and the integrated structure is installed in the containing groove.

13. An external rotor electric motor characterised by, The motor comprises a stator and the rotor assembly according to any one of claims 1 to 12, and the stator is arranged to rotate in the rotor assembly.

14. Household appliance, characterized in that The motor comprises the outer rotor motor according to claim 13.

Images