Electric machine and electric appliance having the same

Abstract

The application discloses a motor and an electrical appliance with the same. The motor comprises a rotor and a stator, the rotor comprises a plurality of permanent magnets arranged at intervals in the circumferential direction of the rotor, and the stator comprises a stator core, the stator core comprises a stator yoke and a plurality of stator tooth shoes, the stator yoke is annular, the plurality of stator tooth shoes are connected to the side of the stator yoke facing the permanent magnets and arranged at intervals in the circumferential direction of the stator yoke, wherein, in the radial direction of the rotor, at least part of the side surface of the permanent magnet facing the stator core is formed into a first arc surface, the side surface of the stator tooth shoe facing the permanent magnet is formed into a tooth shoe arc surface, the first arc surface and the tooth shoe arc surface are both arc cylindrical surfaces extending in the circumferential direction of the rotor and protruding outward in the radial direction, and the ratio between the length of the first arc surface and the length of the tooth shoe arc surface in the circumferential direction of the rotor is 0.8-1.25. According to the motor, 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 electrical equipment, and more particularly to an electric motor and an electrical device having the same. Background Technology

[0002] During the hot season, people use 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 a power source to output power for their operation. However, during operation, the motor generates considerable noise, which significantly reduces 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 provides a motor that can achieve extremely quiet operation, greatly improving the user experience.

[0004] The present invention also proposes an electrical device having the above-mentioned motor.

[0005] According to a first aspect of the present invention, an electric motor includes: a rotor comprising a plurality of permanent magnets arranged at circumferential intervals along the rotor; and a stator arranged radially inner or outer side of the rotor, the stator including a stator core, the stator core including a stator yoke and stator teeth, the stator yoke being annular, the number of stator teeth being plurality of, the plurality of stator teeth being connected to the side of the stator yoke facing the permanent magnets and arranged at circumferential intervals along the stator yoke, wherein, in the radial direction of the rotor, at least a portion of the surface of the permanent magnets facing the stator core is formed as a first arcuate surface, and the surface of the stator teeth facing the permanent magnets is formed as a toothed shoe arcuate surface, the first arcuate surface and the toothed shoe arcuate surface being both arcuate cylindrical surfaces extending circumferentially along the rotor and convex radially outward; in the circumferential direction of the rotor, the ratio between the length of the first arcuate surface and the length of the toothed shoe arcuate surface is 0.8-1.25.

[0006] According to the present invention, by forming at least a portion of the side surface of the permanent magnet facing the stator core as a first arc surface, forming the side surface of the stator tooth shoe facing the permanent magnet as a tooth shoe arc surface, and limiting the ratio of the length of the first arc surface to the length of the tooth shoe arc surface to the range of 0.8 to 1.25, the motor has a good quiet operation and greatly improves the user experience.

[0007] In addition, the motor according to the present invention may also have the following additional technical features:

[0008] In some embodiments of the present invention, the number of stator cores is 12 and the number of permanent magnets is 10.

[0009] In some embodiments of the present invention, the rotor is arranged radially outside the stator, and the rotor further includes a magnetic ring, which is annular and arranged on the side of the plurality of permanent magnets opposite to the stator. In the axial direction of the rotor, the height of the magnetic ring is less than the height of the permanent magnets.

[0010] In one embodiment of the present invention, in the axial direction of the 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 3.5mm-5.5mm.

[0011] In one embodiment of the present invention, the height of the magnetic ring in the axial direction of the rotor is equal to the height of the stator core.

[0012] In one embodiment of the present invention, in the radial direction of the rotor, the thickness of the magnetic ring is 2 / 5 to 3 / 5 of the thickness of the permanent magnet.

[0013] In one embodiment of the present invention, the outer diameter of the magnetic ring is 101mm-105mm.

[0014] In one embodiment 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 rotor.

[0015] In one embodiment of the present invention, the side surface of the permanent magnet facing the stator core further includes: a second arc surface, wherein there are two second arc surfaces and they are respectively connected to the two ends of the first arc surface in the circumferential direction of the rotor, the second arc surface extends along the circumferential direction of the rotor and protrudes in the direction of the central axis of the rotor; and a third arc surface, wherein there are two third arc surfaces and they are respectively connected between the two second arc surfaces and the two end faces of the permanent magnet in the circumferential direction of the rotor.

[0016] In some examples 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.

[0017] 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.

[0018] 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 rotor is 3.5mm-5mm and the width in the radial direction is 1mm-1.5mm.

[0019] In some embodiments of the present invention, the thickness of the permanent magnet in the radial direction of the rotor is 4.5mm-5.5mm.

[0020] In one embodiment of the present invention, the stator tooth shoe includes a stator tooth portion and a stator shoe portion, the stator tooth portion extends radially along the stator yoke portion and is connected at one end to the stator yoke portion, the stator shoe portion is connected to the other end of the stator tooth portion, and the stator shoe portion extends circumferentially along the stator yoke portion.

[0021] In some examples 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.

[0022] In some examples 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.

[0023] In some examples of the present invention, the minimum distance between two adjacent stator shoe portions in the circumferential direction of the stator is 2mm-3mm.

[0024] In some examples of the present invention, the side surface of the stator shoe portion facing away from the stator teeth portion is formed as the tooth shoe arc surface, the tooth shoe arc surface comprising: a first arc segment extending circumferentially along the stator, the stator yoke portion being symmetrical about the perpendicular bisector of the first arc segment; and a second arc segment, the number of which is two, the two second arc segments respectively connecting the first arc segment on both sides of the stator circumferentially.

[0025] In one example of the present invention, 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.

[0026] In one example 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.

[0027] The electrical apparatus according to the second aspect of the invention includes the motor according to the first aspect of the invention.

[0028] According to the electrical device of the present invention, by providing the motor of the first aspect described above, by forming at least a portion of the side surface of the permanent magnet facing the stator core as a first arc surface, forming the side surface of the stator tooth shoe facing the permanent magnet as a tooth shoe arc surface, and limiting the ratio of the length of the first arc surface to the length of the tooth shoe arc surface to the range of 0.8 to 1.25, the motor has a good quiet operation and greatly improves the user experience.

[0029] Additional aspects and advantages of the invention will be set forth in the description which follows, and in some respects will be obvious from the description or may be learned by practice of the invention. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of a motor according to an embodiment of the present invention;

[0031] Figure 2 yes Figure 1 A schematic diagram of the rotor and stator core shown;

[0032] Figure 3 yes Figure 2 A schematic diagram of the permanent magnet shown;

[0033] Figure 4 yes Figure 2 A schematic diagram of the permanent magnet from another angle;

[0034] Figure 5 yes Figure 2 A schematic diagram of the first arc surface without rounded corners;

[0035] Figure 6 yes Figure 2 The diagram shows a stator toothed shoe.

[0036] Figure label:

[0037] 10. 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. Gear shoe arc surface; 2031. First arc segment; 2032. Second arc segment;

[0038] 100. Electric motor. Detailed Implementation

[0039] 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.

[0040] The following is for reference. Figures 1-6 A motor 100 according to an embodiment of the first aspect of the present invention is described.

[0041] like Figures 1-6 As shown, the motor 100 according to a first aspect embodiment of the present invention includes: a rotor 10 and a stator 20. Specifically, the rotor 10 includes a plurality of permanent magnets 12, the plurality of permanent magnets 12 being arranged along the circumference of the rotor 10 (e.g., ...). Figure 1 The stator 20 is arranged at intervals in the L1 direction shown. It employs a structure with multiple permanent magnets 12, which is simple in structure, easy to maintain, and reliable in use; the stator 20 is arranged radially to the rotor 10 (e.g., in the direction L1). Figure 4 The stator 20 includes a stator core 21 on the inner or outer side (as shown in the L3 direction). The stator core 21 includes a stator yoke 211 and stator toothed shoes 212. The stator yoke 211 is annular, and there are multiple stator toothed shoes 212. The multiple stator toothed shoes 212 are connected to the side of the stator yoke 211 facing the permanent magnet 12 and are arranged at intervals in the circumference of the stator yoke 211.

[0042] In the radial direction of the rotor 10, at least a portion of the surface of the permanent magnet 12 facing the stator core 21 is formed as a first arc surface 121, and the surface of the stator tooth shoe 212 facing the permanent magnet 12 is formed as a tooth shoe arc surface 203. Both the first arc surface 121 and the tooth shoe arc surface 203 are arc-shaped cylindrical surfaces that extend circumferentially along the rotor 10 and convex radially outward. In the circumferential direction of the rotor 10, the ratio between the length of the first arc surface 121 and the length of the tooth shoe arc surface 203 is 0.8-1.25. For example, the ratio of the length of the first arc surface 121 to the length of the tooth shoe arc surface 203 can be 0.8, 0.95, 1.1, or 1.25, etc.

[0043] It should be noted that the length of the first arc surface 121 refers to the arc length of the first arc surface 121 on the cross section perpendicular to the axial direction of the stator 20, and the length of the toothed shoe arc surface 203 refers to the arc length of the toothed shoe arc surface 203 on the cross section perpendicular to the axial direction of the stator. The arc lengths of the first arc surface 121 and the toothed shoe arc surface 203 can be calculated using the arc length calculation formula, which is I=n×π×r / 180, where I is the arc length, n is the central angle, and r is the radius.

[0044] In this embodiment, the motor 100 is provided with a plurality of permanent magnets 12 arranged circumferentially along the rotor 10, and at least a portion of the surface of the permanent magnet 12 facing the stator core 21 is formed as a first arc surface 121. The first arc surface 121 protrudes outward along the radial direction of the rotor 10, so that the magnetic flux of the permanent magnet 12 is better concentrated 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.

[0045] The stator is provided with multiple stator teeth 212, and the surface of the stator teeth 212 facing the permanent magnet 12 is formed as a toothed arc surface 203. The toothed arc surface 203 and the first arc surface 121 cooperate to form the air gap structure of the motor 100. Both the toothed arc surface 203 and the first arc surface 121 are set as arc-shaped cylindrical surfaces that extend circumferentially along the rotor 10 and convex radially outward. The ratio of the length of the first arc surface 121 to the length of the toothed arc surface 203 is limited to the range of 0.8 to 1.25, thereby improving and optimizing the air gap structure. This makes the magnetic field formed by the permanent magnet 12 and the stator 20 windings in the air gap more sinusoidal, and causes the air gap magnetic field to concentrate towards the central axis of the permanent magnet 12 and the stator teeth 212 in the radial direction of the rotor 10, thereby reducing the content of back EMF harmonics on the stator 20 and reducing the THD (total harmonic distortion) of the motor 100. The total harmonic distortion (THD) is brought to an optimal range, thereby effectively reducing the noise of the motor 100 during operation and achieving an extremely quiet effect.

[0046] 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 limiting the ratio of the length of the first arc surface 121 to the length of the tooth shoe arc surface 203 within the optimal range, the air gap structure is optimized, the magnetic permeability in the air gap is more uniform, thereby reducing the back electromotive force harmonic and improving the quietness of the motor 100.

[0047] According to an embodiment of the present invention, the motor 100 has a good quiet operation and greatly improves the user experience by forming at least a portion of the side surface of the permanent magnet 12 facing the stator core 21 as a first arc surface 121, forming the side surface of the stator tooth shoe 212 facing the permanent magnet 12 as a tooth shoe arc surface 203, and limiting the ratio of the length of the first arc surface 121 to the length of the tooth shoe arc surface 203 to the range of 0.8 to 1.25.

[0048] In some embodiments of the present invention, such as Figure 2As shown, the number of stator cores 21 can be 12, and the number of permanent magnets 12 can be 10. Therefore, setting the number of stator cores 21 to 12 and the number of permanent magnets 12 to 10 can meet the requirements of the number of stator windings 20 and the magnetic field strength required for the operation of motor 100, so that motor 100 can achieve the performance requirements of design operation and a good operating state.

[0049] In some embodiments of the present invention, such as Figure 1 and Figure 2 As shown, the rotor 10 can be arranged radially outside the stator 20. The rotor 10 may also include a magnetic ring 11, which is annular and arranged on the side of the plurality of permanent magnets 12 away from the stator 20, in the axial direction of the rotor 10 (e.g., ...). Figure 1 In the L2 direction shown, the height of the magnetic ring 11 is less than the height of the permanent magnet 12. This means that the motor 100 is an external rotor motor, which has a simple structure, good heat dissipation, and convenient winding. Of course, the motor 100 can also have other structural forms; for example, the rotor 10 can be arranged radially inside the stator 20. Setting the height of the magnetic ring 11 to be less than the height of the permanent magnet 12 increases the magnetic reluctance of the portion of the permanent magnet 12 that extends above the magnetic ring 11, reduces the magnetic flux, and thus reduces the influence of the magnetic field at the end of the permanent magnet 12 on the magnetic saturation of the stator teeth. This reduces cogging torque, further achieving a quieter operation and improving the user experience.

[0050] It should be noted that stator tooth magnetic saturation refers to the state in which the magnetic induction intensity at the stator tooth section 201 of the stator 20 no longer increases with the increase of current. The reduction of magnetic flux at the end of the permanent magnet 12 reduces the magnetic flux entering the stator tooth section 201, thereby reducing the magnetic induction intensity of the stator tooth section 201.

[0051] 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 powered. Cogging torque has periodic torque fluctuations, which can cause additional torque fluctuations and thus generate noise.

[0052] 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 fluctuation caused by the cogging torque, thus further enabling the motor 100 to have a good quiet operation.

[0053] In one embodiment of the present invention, such as Figure 1As shown, along the axial direction of the rotor 10, both ends of the permanent magnet 12 can extend beyond both ends of the magnetic ring 11, and the height of the portion of the permanent magnet 12 extending beyond the magnetic ring 11 at any end can be 3.5mm-5.5mm. Therefore, by limiting the height of the portion of the permanent magnet 12 extending beyond the magnetic ring 11, the portion extending beyond the magnetic ring 11 can be kept relatively small, 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 ring 11 is sufficiently large allows the motor 100 to have a better noise reduction effect. For example, the height of the portion of the permanent magnet 12 extending beyond the magnetic ring 11 at any end can be 3.5mm, 4.5mm, or 5.5mm, etc. The specific height of the portion of the permanent magnet 12 extending beyond the magnetic ring 11 at any end can be reasonably set according to the actual design requirements of the motor 100.

[0054] In one embodiment of the present invention, reference is made to... Figure 1 As shown, the height of the magnetic ring 11 along the axial direction of the rotor 10 can be equal to the height of the stator core 21. This allows the magnetic ring 11 and the stator core 21 to form a good magnetic flux in height, thereby ensuring good rotational performance of the motor 100 during operation, and also facilitating the assembly and positioning of the magnetic ring 11 and the stator core 21. Of course, the height of the magnetic ring 11 can also be greater than the height of the stator core 21.

[0055] In one embodiment of the present invention, reference is made to... Figure 2 As shown, in the radial direction of the 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 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 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 rotor 10 can be set to 0.45 times the thickness of the permanent magnet 12, or it can be set to 0.5 times the thickness of the permanent magnet 12. The optimal value for the thickness of the magnetic ring 11 can be selected based on the actual magnetic conduction effect.

[0056] In one embodiment of the present invention, reference is made to... Figure 2 As 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 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 one embodiment of the present invention, reference is made to... Figure 1 and 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 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 rotor 10 is the same as the height of the magnetic ring 11 along the axial direction of the rotor 10, and the wall thickness of the magnetic tube is the same as the radial thickness of the magnetic ring 11 along the 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 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 rotor 10. The wall thickness of the magnetic ring 11 is the same as the radial thickness of the magnetic ring 11 along the rotor 10. This structure is simple, and the height of the magnetic ring 11 along the axial direction of the 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] In one embodiment of the present invention, such as Figure 4 As shown, the surface of the permanent magnet 12 facing the stator core 21 may further include: a second arc surface 122 and a third arc surface 123, wherein there are two second arc surfaces 122 and they are respectively connected to the two ends of the first arc surface 121 in the circumferential direction of the rotor 10. The second arc surface 122 extends along the circumferential direction of the rotor 10 and protrudes in the direction of the central axis of the rotor 10; there are two third arc surfaces 123 and they 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 rotor 10. It is understandable that the stator 20 of the motor 100 is located inside the rotor 10, and the radial inner wall of the permanent magnet 12 is designed as a multi-segment arc. When the 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 can make the magnetic flux of the permanent magnet 12 better converge along the radial direction towards the perpendicular bisector of the first inner arc surface 121 of the permanent magnet 12, making the magnetic field in the air gap more sinusoidal, thereby improving the magnetic field and magnetic density of the permanent magnet 12, improving the performance of the motor 100, and reducing the noise of the motor 100 during operation.

[0059] Further, refer to Figure 4 and Figure 5As shown, the second arc surface 122 is formed by rounding the corners at the junction of the first arc surface 121 and the third arc surface 123. The ratio of the effective length of the first arc surface 121 to the length of the toothed shoe arc surface 203 is 0.8 to 1.25. The effective length of the first arc surface 121 refers to the length of the first arc surface 121 before the second arc surface 122 is formed, that is, the length of the first arc surface 121 before the corners are rounded. This makes the design of the ratio of the length of the first arc surface 121 of the permanent magnet 12 to the toothed shoe arc surface 203 more convenient and simple.

[0060] In some examples of the present invention, references Figure 4 As 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.

[0061] In some embodiments of the present invention, reference is made to Figure 3 As shown, the axial end face of the permanent magnet 12 and the radial wall face of the permanent magnet 12 can have a chamfer. As a result, the thickness of the two end portions of the permanent magnet 12 is reduced after the chamfer, 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.

[0062] In one embodiment of the present invention, reference is made to... Figure 3 As shown, the chamfer is a right angle, and its width along the axial direction of the rotor 10 can be 3.5mm-5mm, while its width along the radial direction is 1mm-1.5mm. 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 along the axial direction of the rotor 10 can be 4mm, and the width along the radial direction can be 1.1mm. The specific dimensions of the chamfer along the axial and radial directions of the rotor 10 can be reasonably selected based on the actual effect.

[0063] In some embodiments of the present invention, reference is made to Figure 2As shown, the thickness of the permanent magnet 12 in the radial direction of the rotor 10 can be 4.5mm-5.5mm. Therefore, limiting the thickness of the permanent magnet 12 in the radial direction of the rotor 10 allows the motor 100 to maintain good performance while avoiding stator tooth saturation due to 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 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 rotor 10 can be reasonably set according to actual conditions.

[0064] In one embodiment of the present invention, such as Figure 2 As shown, the stator tooth shoe 212 may include a stator tooth portion 201 and a stator shoe portion 202. The stator tooth portion 201 extends radially along the stator yoke portion 211 and is connected to the stator yoke portion 211 at one end. The stator shoe portion 202 is connected to the other end of the stator tooth portion 201 and extends circumferentially along the stator yoke portion 211. Therefore, the structure is simple and facilitates the fixing of the windings to the stator core 21.

[0065] In some examples of the present invention, references 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 20 can be 1 / 18, 1 / 16, etc., of the outer diameter of the magnetic ring 11. 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.

[0066] In some examples of the present invention, references Figure 2As shown, 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 to 2 / 3. Therefore, limiting the thickness of the stator shoe portion 202 in the radial direction of the stator 20 allows it to have higher structural strength, thus providing good positioning and fixing for the stator 20 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 0.55, 0.6, or 0.65, etc., and the specific ratio can be reasonably set according to actual design and manufacturing needs.

[0067] In some examples of the present invention, references 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 100100. 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 20 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 and processing needs.

[0068] In some examples of the present invention, such as Figure 2 and Figure 6 As shown, the surface of the stator shoe portion 202 facing away from the stator tooth portion 201 can be formed into a tooth shoe arc surface 203. The tooth shoe arc surface 203 includes: a first arc segment 2031 and a second arc segment 2032. The first arc segment 2031 extends circumferentially along the stator 20, and the stator yoke portion 211 is symmetrical about the perpendicular bisector of the first arc segment 2031. There are two second arc segments 2032, which are respectively connected to the first arc segment 2031 on both sides of the stator 20 in the circumferential direction. Therefore, by setting the tooth shoe arc surface 203 in the form of a multi-segment arc, the motor 100 can operate more smoothly, and the magnetic field and magnetic flux density of the permanent magnet 12 on the stator core 21 can be improved, thereby improving the performance of the motor 100 to a certain extent.

[0069] In one example of the invention, reference is made to... Figure 6As shown, the central angle α corresponding to the first arc segment 2031 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 2031, the surface structure design of the air gap side of the stator shoe 202 can better facilitate the uniformity of air gap magnetic permeability, thereby contributing to the quiet operation of the motor 100100. For example, the central angle α corresponding to the first arc segment 2031203 can be 1 / 5 (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.

[0070] In one example of the invention, reference is made to... Figure 6 As shown, the first arc segment 2031 and the second arc segment 2032 can be tangent at the connection point, and the radius R2 of the second arc segment 2032 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 2031 and the second arc segment 2032 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 2032 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.

[0071] 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 the stator tooth shoes 212 to be positioned close to the stator yoke 211, ensuring that the spacing between adjacent stator tooth shoes 212 meets the requirements for winding the stator 20 windings, thus facilitating the processing and assembly of the motor 100. For example, the inner diameter of the stator yoke 211 can be 27mm, 28mm, 29mm, etc., and the size of the inner diameter of the stator yoke 211 can be reasonably set according to actual production and assembly needs.

[0072] 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.

[0073] An electrical device according to a second aspect of the present invention includes a motor 100 according to a first 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 present invention, the electric device is powerful. By setting the motor 100 of the first aspect embodiment above, at least a portion of the side surface of the permanent magnet 12 facing the stator core 21 is formed as a first arc surface 121, and the side surface of the stator tooth shoe 212 facing the permanent magnet 12 is formed as a tooth shoe arc surface 203. The ratio of the length of the first arc surface 121 to the length of the tooth shoe arc surface 203 is limited to the range of 0.8 to 1.25, so that the motor 100 has a good quiet operation and greatly improves the user experience.

[0076] The following will refer to Figures 1-6 An electrical device according to a specific embodiment of the present invention is described.

[0077] like Figures 1-6 As shown, the electrical equipment includes a motor 100, which is an external rotor motor. The motor 100 includes a rotor 10 and a stator 20, with the stator 20 located radially inside the rotor 10.

[0078] The rotor 10 includes a magnetic ring 11 and permanent magnets 12. Multiple permanent magnets 12 are arranged at intervals along the circumference of the magnetic ring 11. The height of the magnetic ring 11 in the axial direction of the rotor 10 is less than the height of the permanent magnets 12. The lengths of the permanent magnets 12 extending beyond the magnetic ring 11 along the axial direction of the rotor 10 are equal. The two end faces of the permanent magnets 12 in the axial direction have chamfers with their radial wall faces, and these chamfers are right angles. The radial inner wall of the permanent magnets 12 forms a first arc surface 121, a second arc surface 122, and a third arc surface 123. The first arc surface 121 protrudes towards the magnetic ring 11. There are two second arc surfaces 122, each connected to one of the first arc surfaces 121 at one of the two ends of the rotor 10 in the circumference direction. There are two third arc surfaces 123, each connected to one of the two second arc surfaces 122 at one of the two ends of the permanent magnets 12 in the circumference direction of the rotor 10. The permanent magnets 12 are symmetrical about the perpendicular bisector of the first arc surface 121.

[0079] 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, with one end of the stator teeth 201 connected to the stator yoke 211 and the other end connected to the stator tooth shoes 212. The stator shoe portion 202 has a toothed shoe arc surface 203 formed on the side surface away from the stator tooth portion 201. The toothed shoe arc surface 203 includes a first arc segment 2031 and a second arc segment 2032. The first arc segment 2031 extends circumferentially along the stator 20. The second arc segment 2032 includes two segments and is connected to the two ends of the first arc segment 2031 circumferentially along the stator 20. The stator toothed shoe 212 is symmetrical about the perpendicular bisector of the first arc segment 2031. The length ratio of the first arc surface 121 to the toothed shoe arc surface 203 is in the range of 0.8 to 1.25. The toothed shoe arc surface 203 and the first arc surface 121 cooperate to form the air gap structure of the motor 100. Both the toothed shoe arc surface 203 and the first arc surface 121 are set as arc-shaped cylindrical surfaces that extend circumferentially along the rotor 10 and convex outward radially. The ratio of the length of the first arc surface 121 to the length of the toothed shoe arc surface 203 is limited to the range of 0.8 to 1.25, so that the air gap structure is improved and optimized. This makes the magnetic field formed by the permanent magnet 12 and the stator 20 winding in the air gap more sinusoidal and causes the air gap magnetic field to concentrate towards the central axis of the permanent magnet 12 and the stator toothed shoe 212 in the radial direction of the rotor 10. This reduces the content of back EMF harmonics on the stator 20, and the THD (total harmonic distortion) of the motor 100 reaches the optimal range, thereby effectively reducing the noise of the motor 100 during operation and achieving an extremely quiet effect.

[0080] 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.

[0081] 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.

[0082] 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.

[0083] 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.

[0084] 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 electric motor, characterized in that, include: A rotor, the rotor comprising a plurality of permanent magnets, the plurality of permanent magnets being arranged at circumferential intervals along the rotor; The stator is arranged radially inside or outside the rotor. The stator includes a stator core, which comprises a stator yoke and stator teeth. The stator yoke is annular, and there are multiple stator teeth connected to the side of the stator yoke facing the permanent magnet and arranged circumferentially at intervals on the stator yoke. Wherein, in the radial direction of the rotor, at least a portion of the surface of the permanent magnet facing the stator core is formed as a first arc surface, and the surface of the stator tooth shoe facing the permanent magnet is formed as a tooth shoe arc surface. Both the first arc surface and the tooth shoe arc surface are arc-shaped cylindrical surfaces that extend circumferentially along the rotor and convex radially outward. In the circumferential direction of the rotor, the ratio between the length of the first arc surface and the length of the tooth shoe arc surface is 0.8-1.

25. The rotor is arranged radially outside the stator, and the rotor further includes a magnetic ring, which is annular and arranged on the side of the plurality of permanent magnets away from the stator. In the axial direction of the rotor, the height of the magnetic ring is less than the height of the permanent magnets. The surface of the permanent magnet facing the stator core also includes: 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 rotor. The second arc surface extends along the circumferential direction of the rotor and protrudes in the direction of the central axis of the 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 rotor; 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.

2. The motor according to claim 1, characterized in that, The number of stator cores is 12, and the number of permanent magnets is 10.

3. The motor according to claim 1, characterized in that, Along the axial direction of the 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 3.5mm-5.5mm.

4. The motor according to claim 1, characterized in that, Along the axial direction of the rotor, the height of the magnetic ring is equal to the height of the stator core.

5. The motor according to claim 1, characterized in that, In the radial direction of the rotor, the thickness of the magnetic ring is 2 / 5 to 3 / 5 of the thickness of the permanent magnet.

6. The motor according to claim 1, characterized in that, The outer diameter of the magnetic ring is 101mm-105mm.

7. The motor according to claim 1, 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 rotor.

8. The motor according to any one of claims 1-7, characterized in that, The permanent magnet has a chamfer between its axial end face and its radial wall face.

9. The motor according to claim 8, characterized in that, The chamfer is a right angle, and the width of the chamfer in the axial direction of the rotor is 3.5mm-5mm and the width in the radial direction is 1mm-1.5mm.

10. The motor according to any one of claims 1-7, characterized in that, The thickness of the permanent magnet in the radial direction of the rotor is 4.5mm-5.5mm.

11. The motor according to any one of claims 1-7, characterized in that, The stator tooth shoe includes a stator tooth portion and a stator shoe portion. The stator tooth portion extends radially along the stator yoke portion and is connected at one end to the stator yoke portion. The stator shoe portion is connected to the other end of the stator tooth portion and extends circumferentially along the stator yoke portion.

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 facing away from the stator teeth portion is formed as the tooth shoe arc surface, and the tooth shoe arc surface includes: The first arc segment extends circumferentially along the stator, and the stator yoke is symmetrical about the perpendicular bisector of the first arc segment; The second arc segment, there are two second arc segments, and the two second arc segments 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 position, 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 1-17.

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