Outer rotor and electric machine and electric appliance having the same

Abstract

The application discloses an outer rotor and a motor and an electrical equipment with the same. The outer rotor comprises a magnetic conducting ring which is annular, and a permanent magnet which is arranged at the radially inner side of the magnetic conducting ring, wherein the permanent magnet comprises a plurality of permanent magnets which are arranged at intervals along the axial direction of the magnetic conducting ring, and the height of the magnetic conducting ring is less than the height of the permanent magnet in the axial direction of the outer rotor. According to the outer rotor, the magnetic conducting ring and the permanent magnet are arranged, and the height of the magnetic conducting ring is less than the height of the permanent magnet, so that the motor has a good mute effect during operation, and the use experience of users is greatly improved.

Description

Technical Field

[0001] This invention relates to the field of electric motor technology, and in particular to an external rotor and an electric motor and electrical equipment having thereon. Background Technology

[0002] During hot seasons, people employ various methods to cool down and achieve a more comfortable living or working environment. Air conditioners, as electrical appliances with excellent cooling performance, are widely favored. Air conditioners typically use a motor as their power source, but the motor generates considerable noise during operation, significantly reducing the user experience. Summary of the Invention

[0003] The present invention aims to at least solve one of the technical problems existing in the prior art. To this end, the present invention proposes an external rotor that can achieve extremely quiet operation of the motor, greatly improving the user experience.

[0004] The present invention also proposes an electric motor having the above-mentioned external rotor.

[0005] The present invention also proposes an electrical device having the above-mentioned motor.

[0006] According to a first aspect of the present invention, an outer rotor includes: a magnetic ring, the magnetic ring being annular; and a permanent magnet disposed radially inside the magnetic ring, the permanent magnet comprising a plurality of such permanent magnets, the plurality of such permanent magnets being arranged at circumferential intervals along the magnetic ring, wherein the height of the magnetic ring is less than the height of the permanent magnet in the axial direction of the outer rotor.

[0007] According to the present invention, the outer rotor is equipped with a magnetic ring and a permanent magnet, and the height of the magnetic ring is less than the height of the permanent magnet, so that the motor has a good quiet operation and greatly improves the user experience.

[0008] In addition, the outer rotor according to the present invention may also have the following additional technical features:

[0009] In some embodiments of the present invention, in the axial direction of the outer rotor, both ends of the permanent magnet extend beyond both ends of the magnetic guide ring, and the height of the portion of either end of the permanent magnet extending beyond the magnetic guide ring is 0.7 to 0.9 times the thickness of the permanent magnet.

[0010] In some embodiments of the present invention, the axial end face of the permanent magnet and the radial wall face of the permanent magnet have a chamfer.

[0011] In one embodiment of the present invention, the chamfer is a right angle, and the width of the chamfer in the axial direction of the outer rotor is 3.5mm-5mm and the width in the radial direction is 1mm-1.5mm.

[0012] In some embodiments of the present invention, the radial inner wall surface of the permanent magnet includes: a first arc surface, which extends circumferentially along the outer rotor and protrudes toward the magnetic ring, and the permanent magnet is symmetrical about the perpendicular bisector of the first arc surface; a second arc surface, which consists of two second arc surfaces and is respectively connected to the two ends of the first arc surface in the circumferential direction of the outer rotor, and extends circumferentially along the outer rotor and protrudes toward the central axis of the outer rotor; and a third arc surface, which consists of two third arc surfaces and is respectively connected between the two second arc surfaces and the two end faces of the permanent magnet in the circumferential direction of the outer rotor.

[0013] In one embodiment of the present invention, the radius R1 of the second arc surface is 1 / 5(D-2T1-2T2) to 1 / 3(D-2T1-2T2), where D is the outer diameter of the magnetic ring, T1 is the thickness of the permanent magnet, and T2 is the thickness of the magnetic ring.

[0014] In some embodiments of the present invention, the thickness of the permanent magnet in the radial direction of the outer rotor is 4.5mm-5.5mm.

[0015] In some embodiments of the present invention, in the radial direction of the outer rotor, the thickness of the magnetic ring is 2 / 5 to 3 / 5 of the thickness of the permanent magnet.

[0016] In some embodiments of the present invention, the outer diameter of the magnetic ring is 101mm-105mm.

[0017] In some embodiments of the present invention, the magnetic ring is a magnetic tube, or the magnetic ring includes a plurality of magnetic sheets, which are stacked along the axial direction of the outer rotor.

[0018] According to a second aspect of the present invention, an electric motor includes an outer rotor according to a first aspect of the present invention; a stator disposed radially inside the outer rotor, the stator including a stator core, wherein the height of the stator core is less than the height of the permanent magnet in the axial direction of the outer rotor.

[0019] According to the present invention, by setting the outer rotor of the first aspect described above, and by setting a magnetic ring and a permanent magnet, wherein the height of the magnetic ring is less than the height of the permanent magnet, the motor has a good quiet operation during operation, which greatly improves the user experience.

[0020] In addition, the motor according to the present invention may also have the following additional technical features:

[0021] In some embodiments of the present invention, the stator core includes a stator yoke and a stator tooth shoe. The stator yoke is annular, and the stator tooth shoe includes a plurality of stator tooth shoes arranged circumferentially at intervals on the stator yoke. The stator tooth shoe includes a stator tooth portion and a stator shoe portion. The stator tooth portion extends radially along the stator yoke and is connected at one end to the stator yoke. The stator shoe portion is connected to the other end of the stator tooth portion and extends circumferentially along the stator yoke.

[0022] In one embodiment of the present invention, the width of the stator teeth in the circumferential direction of the stator is 1 / 20 to 1 / 15 of the outer diameter of the magnetic ring.

[0023] In one embodiment of the present invention, the ratio of the thickness of the stator shoe portion in the radial direction of the stator to the width of the stator tooth portion is 1 / 2 to 2 / 3.

[0024] In one embodiment of the present invention, the minimum distance between two adjacent stator shoe portions in the circumferential direction of the stator is 2mm-3mm.

[0025] In one embodiment of the present invention, the side surface of the stator shoe portion opposite to the stator teeth portion includes: a first arc segment extending circumferentially along the stator, the stator shoe portion being symmetrical about the perpendicular bisector of the first arc segment; and a second arc segment comprising two segments, the two second arc segments respectively connecting the first arc segment on both sides of the stator in the circumferential direction.

[0026] In some examples of the present invention, the corresponding central angle α of the first arc segment satisfies: 1 / 6(360° / Z)≤a≤1 / 4(360° / Z), where Z is the number of stator teeth.

[0027] In some examples of the present invention, the first arc segment and the second arc segment are tangent at the connection position, and the radius R2 of the second arc segment is 1 / 6(D-2T1-2T2) to 1 / 4(D-2T1-2T2), where D is the outer diameter of the magnetic ring, T1 is the thickness of the permanent magnet, and T2 is the thickness of the magnetic ring.

[0028] The electrical apparatus according to the third aspect of the invention includes the motor according to the second aspect of the invention.

[0029] According to the electrical device of the present invention, by providing the motor described in the second aspect above, and by providing a magnetic ring and a permanent magnet, wherein the height of the magnetic ring is less than the height of the permanent magnet, the motor has a good quiet operation, which greatly improves the user experience.

[0030] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of a motor according to an embodiment of the present invention;

[0032] Figure 2 yes Figure 1 A schematic diagram of the outer rotor and stator core shown;

[0033] Figure 3 yes Figure 2 Cross-sectional view of the outer rotor and stator core shown;

[0034] Figure 4 yes Figure 2 A schematic diagram of the permanent magnet shown;

[0035] Figure 5 yes Figure 2 A schematic diagram of the permanent magnet from another angle;

[0036] Figure 6 yes Figure 2 The diagram shows a stator toothed shoe.

[0037] Figure label:

[0038] 10. Outer rotor; 11. Magnetic ring; 12. Permanent magnet; 121. First arc surface; 122. Second arc surface; 123. Third arc surface; 20. Stator; 21. Stator core; 211. Stator yoke; 212. Stator gear shoe; 22. Injection molded part; 201. Stator gear; 202. Stator shoe; 203. First arc segment; 204. Second arc segment;

[0039] 100. Electric motor. Detailed Implementation

[0040] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0041] First, refer to Figures 1-6A brief description is given of the electric motor 100 according to an embodiment of the second aspect of the present invention. The electric motor 100 includes an outer rotor 10 and a stator 20 according to an embodiment of the first aspect of the present invention, the stator has stator teeth 201 for winding windings, the stator 20 is disposed radially inside the outer rotor 10, the outer rotor 10 cooperates with the stator 20, and the electric motor 100 utilizes the principle that a current-carrying conductor is subjected to a force in a magnetic field to make the outer rotor 10 rotate around the axis of the stator 20, thereby outputting rotational torque to the outside.

[0042] In the following, reference is made to Figures 1-6 to describe the outer rotor 10 according to the embodiment of the first aspect of the present invention.

[0043] As shown in Figures 1-6 the outer rotor 10 according to the embodiment of the first aspect of the present invention includes a magnetically conductive ring 11 and permanent magnets 12. Specifically, the magnetically conductive ring 11 is annular; the permanent magnets 12 are arranged on the radially inner side of the magnetically conductive ring 11, the number of the permanent magnets 12 is multiple, the plurality of permanent magnets 12 are arranged at intervals along the circumferential direction of the magnetically conductive ring 11, and in the axial direction of the outer rotor 10, the height of the magnetically conductive ring 11 is smaller than the height of the permanent magnets 12. For example Figure 3 as shown, the height of the magnetically conductive ring 11 is H1, and the height of the permanent magnet 12 is H2, then H1<H2.

[0044] In the outer rotor 10 of the embodiment of the present invention, by providing the magnetically conductive ring 11 and the permanent magnets 12, and making the height of the magnetically conductive ring 11 smaller than the height of the permanent magnets 12, the magnetic reluctance of the magnetic path at the portion where the end of the permanent magnet 12 protrudes beyond the magnetically conductive ring 11 is increased, the magnetic flux is reduced, thereby reducing the influence of the magnetic field at the end of the permanent magnet 12 on the magnetic saturation degree of the stator teeth, so as to reduce the cogging torque, achieve a good silent effect, and greatly improve the user experience. It can be understood that the magnetically conductive ring 11 has a small magnetic reluctance, the magnetic flux of the permanent magnet 12 flows easily, while air has a large magnetic reluctance, and the magnetic flux of the permanent magnet 12 does not flow easily. Thus, between the outer rotor 10 and the stator 20, the magnetic flux at the magnetically conductive ring 11 is larger, and the magnetic flux at the portion where the permanent magnet 12 protrudes beyond the magnetically conductive ring 11 is smaller. It should be noted that the magnetic saturation of the stator teeth refers to a state where the magnetic flux density at the stator teeth 201 of the stator 20 no longer increases with the increase of current, and the reduction of the magnetic flux at the end of the permanent magnet 12 reduces the magnetic flux entering the stator teeth 201, thereby lowering the magnetic flux density of the stator teeth 201.

[0045] It should be noted that cogging torque refers to the torque generated by the interaction between the permanent magnet 12 and the stator core 21 when the motor 100 is not energized. Cogging torque has periodic torque fluctuations, which cause additional torque fluctuations and thus generate noise. The reduction in magnetic flux at the end of the permanent magnet 12 reduces the magnetic induction intensity flowing to the stator core 21, thereby reducing the interaction strength between the permanent magnet 12 and the stator core 21, which in turn reduces the cogging torque and weakens the torque fluctuations caused by the cogging torque, thus enabling the motor 100 to have a good quiet operation.

[0046] According to an embodiment of the present invention, the outer rotor 10, by setting a magnetic ring 11 and a permanent magnet 12, and the height of the magnetic ring 11 being less than the height of the permanent magnet 12, enables the motor 100 to have a good quiet operation, greatly improving the user experience.

[0047] In addition, the outer rotor 10 according to the present invention may also have the following additional technical features:

[0048] In some embodiments of the present invention, reference is made to Figure 3 As shown, in the axial direction of the outer rotor 10, both ends of the permanent magnet 12 can extend beyond both ends of the magnetic guide ring 11, and the height of the portion of the permanent magnet 12 extending beyond the magnetic guide ring 11 at any end can be 0.7 to 0.9 times the thickness of the permanent magnet 12. Therefore, by limiting the height of the portion of the permanent magnet 12 extending beyond the magnetic guide ring 11, the portion extending beyond the magnetic guide ring 11 is not excessive, thus ensuring that the permanent magnet 12 has a high magnetic flux, maintaining a high level of electromagnetic conversion performance of the motor 100, and thus maintaining the good performance of the motor 100. Simultaneously, ensuring that the portion of the permanent magnet 12 extending beyond the magnetic guide ring 11 is sufficiently large allows the motor 100 to have a good noise reduction effect. For example, the height of the portion of the permanent magnet 12 extending beyond the magnetic guide ring 11 at any end can be 0.7, 0.8, or 0.9 times the thickness of the permanent magnet 12, etc., and the specific ratio can be reasonably selected according to the actual noise reduction effect and the performance of the motor 100.

[0049] In some embodiments of the present invention, such as Figure 3 As shown, the axial end face of the permanent magnet 12 and the radial wall face of the permanent magnet 12 may have a chamfer. For example... Figure 3 As shown, the included angle α is the chamfer between the axial end face of the permanent magnet 12 and the radial wall face of the permanent magnet 12. Therefore, the thickness of the two end portions of the permanent magnet 12 is reduced after chamfering, which reduces the magnetic flux at the ends of the permanent magnet 12, thereby further reducing the cogging torque and improving the quietness of the motor 100.

[0050] In one embodiment of the present invention, reference is made to... Figure 4As shown, the chamfer can be a right angle, with a width of 3.5mm-5mm in the axial direction and 1mm-1.5mm in the radial direction for the outer rotor 10. This allows the thickness of the portion of the permanent magnet 12 protruding above the magnetic ring 11 to gradually decrease axially from the center to both ends, resulting in a more uniform variation in the magnetic induction intensity of the permanent magnet 12 along the axial direction. This provides a good magnetic field environment for the permanent magnet 12, ensuring proper operation of the motor 100. For example, the width of the chamfer in the axial direction of the outer rotor 10 can be 3.5mm, and the width in the radial direction can be 1mm. The specific dimensions of the chamfer in the axial and radial directions of the outer rotor 10 can be reasonably selected based on the actual effect.

[0051] In some embodiments of the present invention, such as Figure 5 As shown, the radial inner wall of the permanent magnet 12 may include: a first arc surface 121, a second arc surface 122, and a third arc surface 123. The first arc surface 121 extends circumferentially along the outer rotor 10 and protrudes toward the guide magnet ring 11. The permanent magnet 12 is symmetrical about the perpendicular bisector of the first arc surface 121. There are two second arc surfaces 122, which are respectively connected to the two ends of the first arc surface 121 in the circumferential direction of the outer rotor 10. The second arc surface 122 extends circumferentially along the outer rotor 10 and protrudes toward the central axis of the outer rotor 10. There are two third arc surfaces 123, which are respectively connected between the two second arc surfaces 122 and the two end faces of the permanent magnet 12 in the circumferential direction of the outer rotor 10.

[0052] It is understandable that the stator 20 of the motor 100 is located inside the outer rotor 10, and the radial inner wall of the permanent magnet 12 is designed in the form of a multi-segment arc. When the outer rotor 10 rotates, the permanent magnet 12 can avoid the inner stator 20, thereby making the motor 100 run more smoothly. At the same time, the multi-segment arc structure of the inner wall of the permanent magnet 12 allows the magnetic flux of the permanent magnet 12 to be better concentrated radially toward the perpendicular bisector of the first arc surface 121 on the inner side of the permanent magnet 12, thereby improving the magnetic field and magnetic density of the permanent magnet 12 and improving the performance of the motor 100 to a certain extent. Preferably, the radial inner wall of the permanent magnet 12 can be designed to consist only of the first arc surface 121 and the second arc surface 122, or it can be designed to consist only of the first arc surface 121.

[0053] In one embodiment of the present invention, reference is made to... Figure 5As shown, the radius R1 of the second arc surface 122 is 1 / 5(D-2T1-2T2) to 1 / 3(D-2T1-2T2), where D is the outer diameter of the magnetic ring 11, T1 is the thickness of the permanent magnet 12, and T2 is the thickness of the magnetic ring 11. Therefore, limiting the radius of the second arc surface 122 allows the structural dimensions and shape variations of the inner wall of the permanent magnet 12, formed by the second arc surface 122, the first arc surface 121, and the third arc surface 123, to be within a reasonable range, thereby improving the performance of the motor 100. For example, the radius R1 of the second arc surface 122 can be 1 / 5(D-2T1-2T2), or it can be 1 / 4(D-2T1-2T2). The specific value of the radius of the second arc surface 122 can be reasonably selected based on the actual effect.

[0054] In some embodiments of the present invention, reference is made to Figure 3 As shown, the thickness of the permanent magnet 12 in the radial direction of the outer rotor 10 can be 4.5mm-5.5mm. Therefore, limiting the thickness of the permanent magnet 12 in the radial direction of the outer rotor 10 allows the motor 100 to maintain good performance while avoiding stator tooth saturation caused by excessive thickness of the permanent magnet 12, thus maintaining good operating conditions for the motor 100. For example, the thickness of the permanent magnet 12 in the radial direction of the outer rotor 10 can be 4.5mm, 5mm, 5.5mm, etc., and the specific value of the thickness of the permanent magnet 12 in the radial direction of the outer rotor 10 can be reasonably set according to actual conditions.

[0055] In some embodiments of the present invention, reference is made to Figure 3 As shown, in the radial direction of the outer rotor 10, the thickness of the magnetic ring 11 can be 2 / 5 to 3 / 5 of the thickness of the permanent magnet 12. Therefore, by limiting the thickness of the magnetic ring 11 in the radial direction of the outer rotor 10, the thickness of the magnetic ring 11 can be within an optimal range, thereby ensuring good magnetic conduction and function of the permanent magnet 12 in the outer rotor 10 motor 100, enabling the motor 100 to achieve optimal electric performance. For example, the thickness of the magnetic ring 11 in the radial direction of the outer rotor 10 can be set to 2 / 5 of the thickness of the permanent magnet 12, or it can be set to 1 / 2 of the thickness of the permanent magnet 12. The thickness of the magnetic ring 11 can be selected based on the actual magnetic conduction effect to achieve the optimal value.

[0056] In some embodiments of the present invention, reference is made to Figure 3As shown, the outer diameter of the magnetic ring 11 can be 101mm-105mm. Therefore, limiting the outer diameter of the magnetic ring 11 can, to a certain extent, limit the outer diameter of the outer rotor 10, thus ensuring that the overall structural dimensions of the motor 100 meet design and manufacturing requirements and maintain the compact size of the motor 100. For example, the outer diameter of the magnetic ring 11 can be 101mm, 102mm, 103mm, etc., and the specific value of the outer diameter of the magnetic ring 11 can be reasonably set according to actual design and processing needs.

[0057] In some embodiments of the present invention, such as Figure 2 As shown, the magnetic ring 11 can be a magnetic tube, or the magnetic ring 11 can include multiple magnetic sheets, which are stacked along the axial direction of the outer rotor 10. That is, the magnetic ring 11 can be a single magnetic tube structure, where the height of the magnetic tube along the axial direction of the outer rotor 10 is the same as the height of the magnetic ring 11 along the axial direction of the outer rotor 10, and the wall thickness of the magnetic tube is the same as the radial thickness of the magnetic ring 11 along the outer rotor 10. The inner wall of the magnetic tube abuts against the outer wall of the multiple permanent magnets 12 along the radial direction of the outer rotor 10. The magnetic ring 11 has a simple structure and is easy to manufacture. Alternatively, the magnetic ring 11 can be composed of multiple magnetic sheets, which are annular thin sheets. The multiple magnetic sheets are stacked along the thickness direction to form the magnetic ring 11 with a height along the axial direction of the outer rotor 10. The wall thickness of the magnetic ring 11 is the same as the radial thickness of the magnetic ring 11 along the outer rotor 10. This structure is simple, and the height of the magnetic ring 11 along the axial direction of the outer rotor 10 can be flexibly adjusted according to actual needs during assembly, making assembly convenient. Preferably, the magnetic ring 11 can be formed by winding a strip of steel plate into a ring shape, or by directly cutting a steel pipe, or by stacking or winding silicon steel sheets.

[0058] The following is for reference. Figures 1-6 A motor 100 according to a second aspect embodiment of the present invention is described.

[0059] like Figures 1-6 As shown, the motor 100 according to an embodiment of the present invention includes an outer rotor 10 and a stator 20 according to a first aspect of the present invention. Specifically, the stator 20 is disposed radially inside the outer rotor 10, and the stator 20 includes a stator core 21. In the axial direction of the outer rotor 10, the height of the stator core 21 is less than the height of the permanent magnet 12. It is understood that during the assembly of the motor 100, a controller needs to be installed on the stator core 21 to monitor and control the operation of the motor 100 in real time and to sense and locate the position of the outer rotor 10. Setting the height of the stator core 21 to be less than the height of the permanent magnet 12 can reserve sufficient space for the installation and fixation of the controller. At the same time, the portion of the permanent magnet 12 that is higher than the stator core 21 can meet the distance requirements of the Hall sensor of the control board. Thus, the motor 100 can use Hall sensors to realize the electronic control needs of the rotor, making the electronic control cost of the motor 100 lower.

[0060] According to an embodiment of the present invention, the motor 100, by providing the outer rotor 10 described in the first aspect of the present invention, and by providing a magnetic ring 11 and a permanent magnet 12, wherein the height of the magnetic ring 11 is less than the height of the permanent magnet 12, enables the motor 100 to have a good quiet operation, greatly improving the user experience.

[0061] In some embodiments of the present invention, such as Figure 2 As shown, the stator core 21 may include a stator yoke 211 and stator tooth shoes 212. The stator yoke 211 is annular, and multiple stator tooth shoes 212 are arranged circumferentially around the stator yoke 211. Each stator tooth shoe 212 includes a stator tooth 201 and a stator shoe 202. The stator tooth 201 extends radially along the stator yoke 211 and is connected at one end to the stator yoke 211. The stator shoe 202 is connected to the other end of the stator tooth 201 and extends circumferentially along the stator yoke 211. Therefore, the structure is simple and facilitates the fixing of the windings in the stator core 21.

[0062] In one embodiment of the present invention, reference is made to... Figure 2 As shown, the circumferential width of the stator tooth 201 in the stator 20 can be 1 / 20 to 1 / 15 of the outer diameter of the magnetic ring 11. Limiting the circumferential width of the stator tooth 201 in the stator 20 allows for customized tooth sections with good structural strength, meeting the requirements for fixing the stator windings. Simultaneously, multiple stator tooth shoes 212 are arranged circumferentially along the stator yoke 211, forming a winding and fixing space between adjacent stator tooth shoes 212. Limiting the circumferential width of the stator tooth 201 in the stator 20 ensures that the stator core 21 has sufficient winding and fixing space for winding installation, thus meeting the manufacturing design requirements of the motor 100. For example, the circumferential width of the stator tooth 201 in the stator can be 1 / 20, 1 / 15, etc., of the outer diameter of the magnetic ring 11, and the circumferential width of the stator tooth 201 in the stator 20 can be reasonably set according to the actual design and manufacturing requirements of the motor 100.

[0063] In one embodiment of the present invention, reference is made to... Figure 2 As shown, the ratio of the thickness of the stator shoe portion 202 in the radial direction of the stator to the width of the stator tooth portion 201 can be 1 / 2 to 2 / 3. Therefore, limiting the thickness of the stator shoe portion 202 in the radial direction of the stator allows it to have higher structural strength, thus providing good positioning and fixing for the stator windings when wound between the stator shoe portion 202 and the stator yoke portion 211. For example, the ratio of the thickness of the stator shoe portion 202 in the radial direction of the stator 20 to the width of the stator tooth portion 201 can be 1 / 2, 2 / 3, etc., and the specific ratio can be reasonably set according to actual design and manufacturing needs.

[0064] In one embodiment of the present invention, reference is made to... Figure 2 As shown, the minimum distance between two adjacent stator shoe portions 202 in the circumferential direction of the stator 20 can be 2mm-3mm. Therefore, by limiting the minimum distance between adjacent stator shoe portions 202 in the circumferential direction of the stator 20, the cogging torque can be kept low, which is beneficial for the quiet operation of the motor 100. At the same time, it ensures that there is sufficient distance between two adjacent stator shoe portions 202 in the circumferential direction of the stator 20, allowing the stator windings to be wound smoothly. For example, the minimum distance between two adjacent stator shoe portions 202 in the circumferential direction of the stator 20 can be 2mm, 2.5mm, 3mm, etc., and the value of the minimum distance can be reasonably set according to actual manufacturing needs.

[0065] In one embodiment of the present invention, such as Figure 6 As shown, the surface of the stator shoe portion 202 facing away from the stator tooth portion 201 may include: a first arc segment 203 and a second arc segment 204. The first arc segment 203 extends circumferentially along the stator, and the stator yoke portion 211 is symmetrical about the perpendicular bisector of the first arc segment 203; the second arc segment 204 includes two segments, which are respectively connected to the first arc segment 203 on both sides of the stator 20 in the circumferential direction. Preferably, the surface of the stator shoe portion 202 facing away from the stator tooth portion 201 may only have the first arc segment 203, or it may have the first arc segment 203, the second arc segment 204, and a third arc segment, with the third arc segment having two segments, which are respectively connected to the two second arc segments 204 on the side away from the first arc segment 203.

[0066] The side surface of the stator shoe portion 202 facing away from the stator tooth portion 201 may include a first arc segment 203 and a second arc segment 204. That is, the side surface of the stator shoe portion 202 facing the permanent magnet 12 includes a first arc segment 203 and a second arc segment 204. The multi-arc form can help the outer rotor 10 avoid the permanent magnet 12 when it is running, so that the motor 100 can run more smoothly. At the same time, the multi-arc structure of the stator shoe portion 202 can make the magnetic flux of the permanent magnet 12 better gather along the stator tooth shoe 212 of the stator core 21 toward the stator yoke 211, thereby improving the magnetic field and magnetic density state of the permanent magnet 12 on the stator core 21, and improving the performance of the motor 100 to a certain extent. The gap formed between the stator shoe 202 and the permanent magnet 12 is the air gap of the motor 100. Designing the inner surface of the permanent magnet 12 as a multi-segment arc and the side surface of the stator shoe 202 facing the permanent magnet 12 as a multi-segment arc can improve the structure of the air gap, thereby making the magnetic field formed by the permanent magnet 12 and the stator winding in the air gap more sinusoidal. This causes the air gap magnetic field to concentrate towards the central axis of the permanent magnet 12 and the stator shoe 212 in the radial direction of the outer rotor 10, thereby reducing the content of back EMF harmonics on the stator 20 to a certain extent, and further reducing the noise of the motor 100 during operation, achieving an extremely quiet effect.

[0067] It should be noted that the back electromotive force harmonic is a harmonic electromotive force induced by the magnetic flux density harmonic generated by the harmonic in the air gap magnetomotive force. The magnitude of the back electromotive force harmonic is related to the uniformity of the magnetic permeability of the air gap. The back electromotive force harmonic will cause fluctuations in the magnetic field, thereby generating noise when the motor 100 is running. By setting the wall surface of the air gap side of the permanent magnet 12 and the surface of the air gap side of the stator shoe 202 in the form of a multi-segment arc, the magnetic permeability in the air gap can be made more uniform, thereby reducing the back electromotive force harmonic and improving the quietness of the motor 100.

[0068] In some examples of the present invention, references Figure 2 and Figure 6 As shown, the central angle α of the first arc segment 203 can satisfy: 1 / 6 (360° / Z) ≤ a ≤ 1 / 4 (360° / Z), where Z is the number of stator shoe 212. Therefore, by limiting the central angle of the first arc segment 203, the surface structure design of the stator shoe 202 on the air gap side can better facilitate the uniformity of air gap magnetic permeability, thereby contributing to the quiet operation of the motor 100. For example, the central angle α of the first arc segment 203 can be 1 / 6 (360° / Z), 1 / 4 (360° / Z), etc. The specific value of the central angle α can be reasonably set according to the actual effect and design and manufacturing needs.

[0069] In some examples of the present invention, references Figure 2 and Figure 6As shown, the first arc segment 203 and the second arc segment 204 can be tangent at the connection point, and the radius R2 of the second arc segment 204 is 1 / 6(D-2T1-2T2) to 1 / 4(D-2T1-2T2), where D is the outer diameter of the magnetic ring 11, T1 is the thickness of the permanent magnet 12, and T2 is the thickness of the magnetic ring 11. Therefore, tangency between the first arc segment 203 and the second arc segment 204 at the connection point makes the surface structure of the stator shoe 202 on the air gap side smoother, which is beneficial to the uniformity of air gap magnetic permeability, thus contributing to the quietness of the motor 100. Limiting the radius of the second arc segment 204 allows the surface structure of the stator shoe 202 on the air gap side to cooperate well with the surface structure of the permanent magnet 12 on the air gap side to form a good air gap structure, which is beneficial to the uniformity of air gap magnetic permeability and improves the quietness of the motor 100.

[0070] In some embodiments of the present invention, reference is made to Figure 2 As shown, the inner diameter of the stator yoke 211 is 26mm-33mm. Therefore, limiting the inner diameter of the stator yoke 211 allows for a more precise circumferential alignment of the stator gear shoes 212 near the stator yoke 211, ensuring that the spacing between adjacent stator gear shoes 212 meets the requirements for stator winding, thus facilitating the processing and assembly of the motor 100. For example, the inner diameter of the stator yoke 211 can be 26mm, 27mm, 28mm, etc., and its size can be reasonably set according to actual production and assembly needs.

[0071] In some embodiments of the present invention, such as Figure 1 As shown, the stator 20 may also include an injection-molded part 22, which is sleeved and fixed on the stator core 21. This can provide insulation for the windings wound on the stator core 21, keeping the motor 100 in good operating condition. The structure is simple and the insulation effect is good.

[0072] The following is for reference. Figures 1-6 An electrical device according to an embodiment of a third aspect of the present invention is described.

[0073] like Figures 1-6 As shown, the electrical device according to an embodiment of the present invention includes a motor 100 according to a second aspect of the present invention.

[0074] Other configurations and operations of the electrical equipment according to embodiments of the present invention are known to those skilled in the art and will not be described in detail here.

[0075] According to the electrical equipment of the present invention, by providing the motor 100 of the second aspect of the present invention, and by providing a magnetic ring 11 and a permanent magnet 12, wherein the height of the magnetic ring 11 is less than the height of the permanent magnet 12, the motor 100 has a good quiet operation, which greatly improves the user experience.

[0076] The following will refer to Figures 1-6 A motor 100 according to a specific embodiment of the present invention is described.

[0077] like Figures 1-6 As shown, the motor 100 includes an outer rotor 10 and a stator 20, with the stator 20 located radially inside the outer rotor 10.

[0078] The outer rotor 10 includes a magnetic ring 11 and permanent magnets 12. Multiple permanent magnets 12 are arranged circumferentially around the magnetic ring 11. The height of the magnetic ring 11 along the axial direction of the outer rotor 10 is less than the height of the permanent magnets 12. The lengths of the permanent magnets 12 extending axially beyond the magnetic ring 11 at both ends of the outer rotor 10 are equal. The two end faces of the permanent magnets 12 along the axial direction have chamfers with the radial wall surface; these chamfers are right angles. The radial inner wall of the permanent magnet 12 includes a first arc surface 121, a second arc surface 122, and a third arc surface 123. The first arc surface 121 protrudes toward the guide magnet ring 11. There are two second arc surfaces 122, which are respectively connected to the two ends of the first arc surface 121 in the circumferential direction of the outer rotor 10. There are two third arc surfaces 123, which are respectively connected to the two second arc surfaces 122 and the two ends of the permanent magnet 12 in the circumferential direction of the outer rotor 10. The permanent magnet 12 is symmetrical about the perpendicular bisector of the first arc surface 121.

[0079] According to an embodiment of the present invention, the outer rotor 10, by setting a magnetic guide ring 11 and a permanent magnet 12, and the height of the magnetic guide ring 11 is less than the height of the permanent magnet 12, reduces the magnetic flux at the end of the permanent magnet 12, thereby reducing the magnetic induction intensity flowing to the stator core 21. This reduces the interaction strength between the permanent magnet 12 and the stator core 21, reduces the cogging torque, and weakens the torque fluctuation caused by the cogging torque. As a result, the motor 100 has a good quiet operation during use, greatly improving the user experience.

[0080] The stator 20 includes a stator core 21 and an injection-molded part 22, which wraps around the stator core 21. The stator core 21 includes a stator yoke 211 and a plurality of stator tooth shoes 212, which are arranged at intervals along the circumference of the stator yoke 211. The stator tooth shoes 212 include stator teeth 201 and stator shoe parts 202. One end of the stator teeth 201 is connected to the stator yoke 211, and the other end is connected to the stator tooth shoes 212. The side surface of the stator shoe part 202 away from the stator teeth 201 includes a first arc segment 203 and a second arc segment 204. The first arc segment 203 extends circumferentially along the stator, and the second arc segment 204 includes two segments, which are respectively connected to the two ends of the first arc segment 203 in the circumferential direction of the stator. The stator tooth shoes 212 are symmetrical about the perpendicular bisector of the first arc segment 203.

[0081] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0082] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0083] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0084] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0085] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. An external rotor, characterized in that, include: Magnetic ring, wherein the magnetic ring is annular; A permanent magnet is arranged radially inside the magnetic guide ring. The permanent magnet includes multiple permanent magnets, which are arranged at intervals along the circumference of the magnetic guide ring. In the axial direction of the outer rotor, the height of the magnetic guide ring is less than the height of the permanent magnet. The radial inner wall surface of the permanent magnet includes: The first arc surface extends circumferentially along the outer rotor and bulges toward the magnetic ring, and the permanent magnet is symmetrical about the perpendicular bisector of the first arc surface. The second arc surface, there are two of them and they are respectively connected to the two ends of the first arc surface in the circumferential direction of the outer rotor. The second arc surface extends along the circumferential direction of the outer rotor and protrudes in the direction of the central axis of the outer rotor. The third arc surface consists of two arc surfaces, which are respectively connected between the two second arc surfaces and the two end faces of the permanent magnet in the circumferential direction of the outer rotor.

2. The external rotor according to claim 1, characterized in that, Along the axial direction of the outer rotor, both ends of the permanent magnet extend beyond both ends of the magnetic guide ring, and the height of the portion of the permanent magnet extending beyond the magnetic guide ring at any end is 0.7 to 0.9 times the thickness of the permanent magnet.

3. The external rotor according to claim 1, characterized in that, The permanent magnet has a chamfer between its axial end face and its radial wall face.

4. The external rotor according to claim 3, characterized in that, The chamfer is a right angle, and the width of the chamfer in the axial direction of the outer rotor is 3.5mm-5mm and the width in the radial direction is 1mm-1.5mm.

5. The external rotor according to claim 1, characterized in that, The radius of the second arc surface R1 = 1 / 5 (D-2T1-2T2) ~ 1 / 3 (D-2T1-2T2), where D is the outer diameter of the magnetic ring, T1 is the thickness of the permanent magnet, and T2 is the thickness of the magnetic ring.

6. The external rotor according to claim 1, characterized in that, The thickness of the permanent magnet in the radial direction of the outer rotor is 4.5mm-5.5mm.

7. The external rotor according to any one of claims 1-6, characterized in that, In the radial direction of the outer rotor, the thickness of the magnetic guide ring is 2 / 5 to 3 / 5 of the thickness of the permanent magnet.

8. The external rotor according to any one of claims 1-6, characterized in that, The outer diameter of the magnetic ring is 101mm-105mm.

9. The external rotor according to any one of claims 1-6, characterized in that, The magnetic ring is a magnetic tube, or the magnetic ring includes multiple magnetic sheets, which are stacked along the axial direction of the outer rotor.

10. An electric motor, characterized in that, include: The outer rotor according to any one of claims 1-9; The stator is located radially inside the outer rotor. The stator includes a stator core, and the height of the stator core is less than the height of the permanent magnet in the axial direction of the outer rotor.

11. The motor according to claim 10, characterized in that, The stator core includes a stator yoke and a stator tooth shoe. The stator yoke is annular, and the stator tooth shoe includes a plurality of stator tooth shoes. The plurality of stator tooth shoes are arranged circumferentially at intervals on the stator yoke. The stator tooth shoe includes a stator tooth and a stator shoe portion. The stator tooth extends radially along the stator yoke and is connected at one end to the stator yoke. The stator shoe portion is connected to the other end of the stator tooth and extends circumferentially along the stator yoke.

12. The motor according to claim 11, characterized in that, The width of the stator teeth in the circumferential direction of the stator is 1 / 20 to 1 / 15 of the outer diameter of the magnetic ring.

13. The motor according to claim 11, characterized in that, The ratio of the thickness of the stator shoe portion in the radial direction of the stator to the width of the stator tooth portion is 1 / 2 to 2 / 3.

14. The motor according to claim 11, characterized in that, The minimum distance between two adjacent stator shoe parts in the circumferential direction of the stator is 2mm-3mm.

15. The motor according to claim 11, characterized in that, The side surface of the stator shoe portion opposite to the stator teeth portion includes: The first arc segment extends circumferentially along the stator, and the stator shoe portion is symmetrical about the perpendicular bisector of the first arc segment; The second arc segment comprises two segments, which are respectively connected to the first arc segment on both sides of the stator in the circumferential direction.

16. The motor according to claim 15, characterized in that, The central angle α corresponding to the first arc segment satisfies: 1 / 6 (360° / Z) ≤ a ≤ 1 / 4 (360° / Z), where Z is the number of stator teeth.

17. The motor according to claim 15, characterized in that, The first arc segment and the second arc segment are tangent at the connection point, and the radius of the second arc segment R2 = 1 / 6 (D-2T1-2T2) ~ 1 / 4 (D-2T1-2T2), where D is the outer diameter of the magnetic ring, T1 is the thickness of the permanent magnet, and T2 is the thickness of the magnetic ring.

18. An electrical appliance, characterized in that, Includes the motor according to any one of claims 11-17.

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