Electric machine and household appliance

Abstract

The application discloses a motor and a household appliance, and relates to the technical field of motors, wherein the motor comprises a rotor assembly and a stator assembly; the number of winding grooves of the stator core of the stator assembly is 18, and the number of permanent magnets of the rotor assembly is 14; the relationship among motor copper loss, iron loss and winding coefficient can be optimized; the copper loss and the iron loss are reduced, the winding coefficient is improved, and thus the efficiency of the motor is improved. The ratio of Di / Dout can affect the size, the iron loss, the magnetic load and the efficiency of the motor, and D0 / Lm reflects the reciprocal of the placement rate of the permanent magnet. Under the condition of 18 slots and 14 poles, by limiting the value of D0 / Lm*Di / Dout to 1 / 8-3 / 8, the magnetic flux can be improved under the condition of guaranteeing the balance between the iron loss and the working efficiency of the motor, and thus the performance of the motor is improved.

Description

Technical Field

[0001] This invention relates to the field of motor technology, and in particular to a motor and a household appliance. Background Technology

[0002] In related technologies, an electric motor includes a stator assembly and a rotor assembly. When the rotor assembly is embedded inside the stator assembly, it constitutes an internal rotor motor. The rotor assembly includes a rotor core and permanent magnets, and the rotor core has mounting slots for mounting the permanent magnets. The magnetic field generated by the permanent magnets interacts with the magnetic field generated by the windings of the stator assembly, causing the rotor assembly to rotate. The magnitude of the magnetic flux of the permanent magnets affects the output performance of the motor, such as torque, speed, and efficiency. Traditional motors have poorly designed rotor core structures, resulting in a small permanent magnet volume that the mounting slots can accommodate, leading to a lower magnetic flux and affecting motor performance. 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 a motor that can increase magnetic flux to improve motor performance.

[0004] The present invention also proposes a household appliance having the above-mentioned motor.

[0005] An electric motor according to a first aspect embodiment of the present invention includes:

[0006] The rotor assembly includes a rotor core, a plurality of permanent magnets and a rotating shaft. The rotating shaft is connected to the inner side of the rotor core. The rotor core is provided with a plurality of mounting slots arranged circumferentially along the rotating shaft. The plurality of permanent magnets are correspondingly mounted in the plurality of mounting slots.

[0007] A stator assembly is wound around the outside of the rotor assembly. The stator assembly includes a stator core, which has a plurality of winding slots arranged circumferentially along the shaft.

[0008] The number of winding slots is 18, and the number of permanent magnets is 14; the maximum outer diameter of the stator core is Dout, the minimum inner diameter of the stator core is Di, the maximum diameter of the rotating shaft is D0, and the distance between two permanent magnets arranged radially opposite each other along the rotating shaft is Lm, satisfying the following:

[0009]

[0010] The motor according to embodiments of the present invention has at least the following beneficial effects:

[0011] By setting the number of winding slots in the stator core of the stator assembly to 18 and the number of permanent magnets in the rotor assembly to 14 (i.e., an 18-slot, 14-pole motor), the relationship between copper loss, iron loss, and winding coefficient can be optimized. This achieves the goal of reducing copper and iron losses while increasing the winding coefficient, thereby improving motor efficiency. The Di / Dout ratio affects the motor's size, iron loss, magnetic load, and efficiency. If the Di / Dout ratio is too small, it indicates that the rotor assembly is small and the magnetic load is low. Under the same output torque, the current is large, leading to increased copper loss and decreased motor efficiency. If the Di / Dout ratio is too large, it indicates that the rotor assembly is large and the stator area is small, resulting in a smaller winding slot area. With the number of winding turns remaining unchanged, the diameter of the copper wire in the winding needs to be reduced, leading to increased resistance and thus increased copper loss. This also results in a large magnetic load, high magnetic density, and high iron loss, further reducing motor efficiency. D0 is the diameter of the shaft, and Lm is the distance between two relatively positioned permanent magnets. Lm reflects the space utilization rate of the rotor core. The larger Lm is, the more space in the rotor core is not used to install permanent magnets. Therefore, D0 / Lm reflects the reciprocal of the permanent magnet placement rate. The smaller D0 / Lm is, the lower the space utilization rate and the smaller the magnetic flux; the larger D0 / Lm is, the higher the space utilization rate and the larger the magnetic flux, but this will result in insufficient space between the shaft and the rotor core to fill the connecting materials, such as plastic sealing materials or rubber. Under the condition of 18 slots and 14 poles, by limiting the value of D0 / Lm×Di / Dout to between 1 / 8 and 3 / 8, the magnetic flux can be increased while ensuring the balance of iron loss and working efficiency of the motor, thereby improving the performance of the motor.

[0012] According to some embodiments of the present invention, the width of the permanent magnet is hpm, and the stator core includes teeth with a width of Wt, satisfying:

[0013]

[0014] According to some embodiments of the present invention, the rotor core includes a plurality of sector-shaped portions arranged circumferentially along the rotating shaft, with the mounting groove formed between two adjacent sector-shaped portions. The maximum width of the sector-shaped portion along the circumferential direction of the rotating shaft is Wr. The stator core includes tooth tips, the maximum width of which is Wt0, satisfying:

[0015]

[0016] According to some embodiments of the present invention, the rotor core includes a plurality of sector-shaped portions arranged circumferentially along the rotating shaft, the maximum length of the sector-shaped portions being Lr along the radial direction of the rotating shaft, and the stator core including tooth tips with a maximum width Wt0, satisfying:

[0017]

[0018] According to some embodiments of the present invention, the maximum distance between the bottoms of the two winding slots arranged radially opposite each other along the rotating shaft is Li, and the height of the permanent magnet along the axial direction of the rotating shaft is H, satisfying:

[0019]

[0020] According to some embodiments of the present invention, the stator core includes a yoke and a plurality of stator teeth, the plurality of stator teeth being arranged circumferentially at intervals on the inner side of the yoke along the axis of rotation. The width of the yoke is Wy along the radial direction of the axis of rotation. Each stator tooth includes a tooth portion and a tooth tip. The tooth portion is connected to the yoke, and the tooth tip is connected to the side of the tooth portion away from the yoke. The width of the tooth portion is Wt, satisfying:

[0021]

[0022] According to some embodiments of the present invention, the rotor core includes a plurality of sector-shaped portions arranged circumferentially along the rotating shaft, wherein the maximum width of the sector-shaped portions along the circumferential direction of the rotating shaft is Wr, and the maximum length of the sector-shaped portions along the radial direction of the rotating shaft is Lr, satisfying:

[0023]

[0024] According to some embodiments of the present invention, the rotor core includes a bushing arranged circumferentially around the rotating shaft, and a plurality of sector portions arranged circumferentially at intervals along the rotating shaft, the bushing being connected to the rotating shaft, and some of the sector portions being connected to the bushing via connecting bridges.

[0025] According to some embodiments of the present invention, the rotor core includes a bushing arranged circumferentially around the rotating shaft, and a plurality of sector portions arranged circumferentially at intervals along the rotating shaft, the bushing being spaced apart from the plurality of sector portions.

[0026] A household appliance according to a second aspect of the present invention includes the motor described in the above embodiments.

[0027] The household appliances according to embodiments of the present invention have at least the following beneficial effects:

[0028] The motor using the first aspect embodiment has 18 winding slots in the stator core of the stator assembly and 14 permanent magnets in the rotor assembly, making it an 18-slot, 14-pole motor. This optimizes the relationship between copper losses, iron losses, and winding coefficients, reducing copper and iron losses while increasing the winding coefficient, thereby improving motor efficiency. The Di / Dout ratio affects the motor's size, iron losses, magnetic load, and efficiency. A Di / Dout ratio that is too small indicates a small rotor assembly and low magnetic load, resulting in a large current for the same output torque, leading to increased copper losses and reduced motor efficiency. Conversely, a Di / Dout ratio that is too large indicates a large rotor assembly and a small stator area, resulting in a smaller winding slot area. With the number of winding turns remaining constant, the copper wire diameter needs to be reduced, leading to increased resistance and thus increased copper losses. This also results in a large magnetic load, high magnetic density, and high iron losses, further reducing motor efficiency. D0 is the diameter of the shaft, and Lm is the distance between two relatively positioned permanent magnets. Lm reflects the space utilization rate of the rotor core. The larger Lm is, the more space in the rotor core is not used to install permanent magnets. Therefore, D0 / Lm reflects the reciprocal of the permanent magnet placement rate. The smaller D0 / Lm is, the lower the space utilization rate and the smaller the magnetic flux; the larger D0 / Lm is, the higher the space utilization rate and the larger the magnetic flux, but this will result in insufficient space between the shaft and the rotor core to fill the connecting materials, such as plastic sealing materials or rubber. Under the condition of 18 slots and 14 poles, by limiting the value of D0 / Lm×Di / Dout to between 1 / 8 and 3 / 8, the magnetic flux can be increased while ensuring the balance of iron loss and working efficiency of the motor, thereby improving the performance of the motor.

[0029] 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

[0030] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

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

[0032] Figure 2 This is a schematic diagram of a rotor assembly according to an embodiment of the present invention, showing a permanent magnet and a mounting slot separated.

[0033] Figure 3 This is a schematic diagram of the structure of a sector-shaped portion according to an embodiment of the present invention;

[0034] Figure 4 This is a schematic diagram of the stator core structure according to an embodiment of the present invention;

[0035] Figure 5 for Figure 4 Enlarged view of point A in the middle;

[0036] Figure 6 This is a partial structural diagram of a motor according to an embodiment of the present invention;

[0037] Figure 7 This is a schematic diagram of the structure of a motor according to another embodiment of the present invention;

[0038] Figure 8 This is a schematic diagram of the structure of a motor according to another embodiment of the present invention;

[0039] Figure 9 This is a schematic diagram of the structure of a motor according to another embodiment of the present invention;

[0040] Figure 10 This is a schematic diagram of the rotor assembly according to another embodiment of the present invention;

[0041] Figure 11 This is a schematic diagram of the rotor assembly according to another embodiment of the present invention;

[0042] Figure 12 This is a bar chart reflecting the influence of the number of winding slots and the number of permanent magnets on the winding coefficient in one embodiment of the present invention;

[0043] Figure 13 This is a line graph reflecting the relationship between the number of winding slots and the size of the winding ends in one embodiment of the present invention;

[0044] Figure 14 This is a line graph illustrating the relationship between the number of permanent magnets and the amount of iron loss in one embodiment of the present invention.

[0045] Icon labels:

[0046] Motor 1000;

[0047] Rotor assembly 100; rotor core 110; sector 111; mounting groove 112; first protrusion 113; first slot 114; permanent magnet 120; first sidewall 121; second sidewall 122; shaft 130; bushing 140; second protrusion 141; connecting bridge 142;

[0048] Stator assembly 200; stator core 210; yoke 211; stator tooth 212; tooth portion 213; tooth tip 214; winding slot 215; second slot opening 216; winding 220. Detailed Implementation

[0049] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown 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 are only used to explain the present invention, and should not be construed as limiting the present invention.

[0050] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, etc., are based on the orientation or positional relationship shown in the drawings and are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0051] In the description of this invention, "multiple" refers to two or more. The use of "first" and "second" is for distinguishing technical features only and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features or their sequential relationship.

[0052] In the description of this invention, unless otherwise explicitly defined, terms such as "setting," "installing," and "connecting" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0053] Electric motors play a vital role in household appliances. Examples include the motors that drive the fan in air conditioners, the motor assemblies inside compressors, the motors in washing machines, and the motors in dishwashers. With the development of the home appliance industry, miniaturization and high power have become the development direction for the next generation of motors.

[0054] An electric motor generally includes a stator assembly and a rotor assembly. The rotor assembly rotates about the motor's rotation axis, and the stator assembly is arranged around the rotation axis. Under the influence of an electromagnetic field, the rotor assembly can rotate relative to the stator assembly, thereby driving the load connected to the motor's output terminal to rotate. It is understood that in one embodiment, the stator assembly is configured to be arranged around the outer side of the rotor assembly, forming an inner rotor motor; in another embodiment, the stator assembly is configured to be arranged around the inner side of the rotor assembly, forming an outer rotor motor.

[0055] To facilitate understanding of the embodiments of the present invention, the following description uses an internal rotor motor as an example.

[0056] Reference Figure 1 , Figure 2 and Figure 3As shown in the embodiment of the present invention, the motor 1000 includes a rotor assembly 100 and a stator assembly 200. The rotor assembly 100 includes a rotor core 110, a shaft 130, and a plurality of permanent magnets 120. The shaft 130 is connected to the inner side of the rotor core 110. The rotor core 110 includes a plurality of sector-shaped portions 111 arranged circumferentially along the shaft 130. A mounting groove 112 for mounting the permanent magnets 120 is formed between two adjacent sector-shaped portions 111. The cross-section of the permanent magnets 120 can be square, rhomboid, trapezoidal, wedge-shaped, or other shapes. The assembled rotor core 110, the plurality of permanent magnets 120, and the shaft 130 are connected by an integral injection molding process, which is the plastic coating treatment of the rotor assembly 100.

[0057] Reference Figure 1 and Figure 4 As shown, the stator assembly 200 is wound around the outside of the rotor assembly 100. The stator assembly 200 includes a stator core 210, an insulating frame, and windings 220. The assembled stator core 210, insulating frame, and windings 220 are connected by an integral injection molding process, which is the plastic coating treatment of the stator assembly 200. It should be noted that the plastic coating treatment of the stator assembly 200 generally simultaneously molds part of the motor 1000 housing, thereby facilitating rapid assembly with the rotor assembly 100. After plastic coating treatment, both the rotor assembly 100 and the stator assembly 200 can obtain a more stable structure, making it less likely for internal components to separate and improving the connection stability between components.

[0058] Reference Figure 4 As shown, the stator core 210 includes a yoke 211 and multiple stator teeth 212. The yoke 211 is annular and arranged circumferentially around the shaft 130. The multiple stator teeth 212 are spaced apart along the axis of the shaft 130 on the inner side of the yoke 211. For example, the stator teeth 212 and the yoke 211 can be integrally formed or connected by fasteners, welding, or other methods. A winding groove 215 is formed between two adjacent stator teeth 212. An insulating frame is inserted into the winding groove 215 to form an insulating layer inside the winding groove 215, so that the winding 220 can meet the electrical insulation requirements when wound on the stator teeth 212 through the winding groove 215. The stator tooth 212 includes a tooth portion 213 and a tooth tip 214. One end of the tooth portion 213 is connected to the inner wall of the yoke portion 211, and the other end is connected to the tooth tip 214. That is, the tooth tip 214 is located on the side of the tooth portion 213 away from the yoke portion 211 and is located inside the yoke portion 211.

[0059] The number of winding slots 215 is 18, and the number of permanent magnets 120 is 14, meaning the motor 1000 is an 18-slot, 14-pole motor 1000. It should be noted that, referring to... Figure 7As shown, in another embodiment, the rotor core 110 has multiple mounting slots 112 spaced around the rotating shaft 130 near its edge, and each mounting slot 112 contains a corresponding permanent magnet 120, with a total of 14 permanent magnets 120. (Refer to...) Figure 8 As shown, in another embodiment, the rotor core 110 has a plurality of mounting slots 112 spaced around the rotating shaft 130 near its edge. Each mounting slot 112 has a first slot segment and a second slot segment that are angled together and connected. A magnetic component is disposed in each of the first and second slot segments. It should be noted that in this embodiment, two magnetic components within one mounting slot 112 constitute one permanent magnet 120; that is, the number of magnetic components is 28, and the number of permanent magnets 120 is 14. (Refer to...) Figure 9 As shown, in another embodiment, a plurality of permanent magnets 120 are provided in the gap between the rotor core 110 and the rotor assembly 100, surrounding the rotor core 110, and the permanent magnets 120 are spaced apart, with a total number of 14 permanent magnets 120.

[0060] Understandably, referring to Figure 12 As shown, Figure 12 The horizontal axis represents the motor 1000 with different numbers of winding slots 215 and permanent magnets 120, while the vertical axis represents the magnitude of the winding coefficient 220. It should be noted that 9S6P on the horizontal axis indicates 9 winding slots 215 and 6 permanent magnets 120, while 18S14P indicates 18 winding slots 215 and 14 permanent magnets 120; that is, S represents winding slot 215 and P represents permanent magnet 120. (Refer to...) Figure 13 and Figure 14 As shown, Figure 13 The horizontal axis represents the number of winding slots 215, and the vertical axis represents the size of the end of the winding 220. The end of the winding 220 refers to the part of the winding 220 that extends beyond the two ends of the iron core. The triangle symbol in the curve represents the size of the end of the winding 220 corresponding to the 18 slots in this embodiment. Figure 14 The horizontal axis represents the number of permanent magnets 120, also known as the number of poles, while the vertical axis represents the amount of iron loss. The triangle symbol in the curve represents the amount of iron loss corresponding to 14 poles in this embodiment.

[0061] Generally speaking, the higher the winding coefficient (220), the better. Figure 12 As can be seen from the data, the winding coefficient of the 18-slot, 14-pole motor 1000 is 0.9. Although this is lower than that of the 9-slot, 8-pole, 9-slot, 10-pole, 12-slot, 10-pole, 12-slot, 14-pole, and 18-slot, 16-pole motors 1000, according to... Figure 13 and Figure 14It is known that the size of the winding 220 end is inversely proportional to the number of winding slots 215. As the number of winding slots 215 increases, the size of the winding 220 end decreases. The size of the winding 220 end is positively correlated with copper loss, thus reducing copper loss. Iron loss is directly proportional to the square of the number of permanent magnets 120; the more permanent magnets 120, the greater the iron loss. Therefore, the copper loss of the 18-slot 14-pole motor 1000 in this embodiment is lower than that of the 9-slot 8-pole motor 1000, 9-slot 10-pole motor 1000, 12-slot 10-pole motor 1000, and 12-slot 14-pole motor 1000, while its iron loss is lower than that of the 18-slot 16-pole motor 1000. In other words, the 18-slot 14-pole motor 1000 of this embodiment combines a high winding 220 coefficient, low copper loss, and low iron loss, resulting in a high efficiency for the motor 1000.

[0062] It should be noted that copper loss refers to the loss generated when current flows through the copper wire of winding 220 during normal operation of motor 1000. Iron loss refers to the loss caused by changes in magnetic flux, occurring in stator core 210 and rotor core 110, and mainly includes hysteresis loss, eddy current loss, and Joule loss. Hysteresis loss and eddy current loss are related to the material and size of rotor core 110, as well as the rate and magnitude of magnetic flux change. Joule loss is related to the magnitude and frequency of the current, as well as the material and size of rotor core 110.

[0063] Reference Figure 4 As shown, the maximum outer diameter of the stator core 210 is Dout, and the minimum inner diameter of the stator core 210 is Di. It should be noted that when the outer and inner sides of the stator core 210 are not circular, the maximum outer diameter refers to the diameter of the circumscribed circle of the stator core 210, and the minimum inner diameter refers to the diameter of the inscribed circle of the stator core 210.

[0064] To increase the magnetic flux of motor 1000, refer to Figure 2 As shown, in the embodiment of the present invention, the maximum diameter of the rotating shaft 130 is D0. When the rotating shaft 130 is provided with features such as grooves and notches, the maximum diameter of the rotating shaft 130 refers to the diameter of the circumscribed circle of the rotating shaft 130. The distance between two permanent magnets 120 arranged radially opposite each other along the rotating shaft 130 is Lm. For example, the side of one permanent magnet 120 facing the other permanent magnet 120 is the first sidewall 121, and the side of the other permanent magnet 120 is the second sidewall 122. The distance between the first sidewall 121 and the second sidewall 122 is Lm, satisfying:

[0065]

[0066] For example, the value can be 3 / 16, 1 / 4, 5 / 16, etc. When the maximum outer diameter Dout of the stator core 210 remains unchanged, and the minimum inner diameter Di of the stator core 210 increases, the area of ​​the winding slot 215 decreases. If the number of turns of the winding 220 remains unchanged, and the same number of turns of the winding 220 are to be wound in a narrower winding slot 215, the diameter of the copper wire in the winding 220 needs to be reduced. However, a smaller wire diameter increases resistance, thus increasing copper losses. Simultaneously, the internal space of the stator core 210 increases, and the radial dimension of the rotor assembly 100 needs to be increased accordingly, meaning the volume of the permanent magnet 120 also increases. This increases the magnetic load and magnetic flux density of the motor 1000, leading to increased iron losses and reduced efficiency of the motor 1000. When the minimum inner diameter Di of the stator core 210 decreases, the area of ​​the winding slot 215 increases, copper losses decrease, the radial dimension of the rotor assembly 100 decreases, the magnetic load decreases, and iron losses decrease. When the minimum inner diameter Di of the stator core 210 remains constant, and the maximum outer diameter Dout of the stator core 210 increases, the volume of the stator core 210 increases, leading to an increase in the overall volume of the motor 1000. Since the radial dimension of the rotor assembly 100 remains constant, the volume of the permanent magnet 120 does not increase. Under constant magnetic load, iron loss is proportional to the volume of the stator core 210; therefore, an increase in the volume of the stator core 210 will lead to an increase in the iron loss of the motor 1000. When the maximum outer diameter Dout of the stator core 210 decreases, the radial dimension of the motor 1000 decreases, and the iron loss of the motor 1000 decreases. However, due to the decrease in the area of ​​the winding slot 215, copper loss will increase. In one embodiment, the maximum outer diameter Dout of the stator core 210 can be 87 mm, and the minimum inner diameter Di of the stator core 210 can be 55.8 mm.

[0067] Therefore, Di / Dout primarily reflects the overall size of motor 1000 and its impact on copper and iron losses. A Di / Dout ratio that is too small indicates a small rotor assembly 100 with low magnetic load. Under the same output torque, this results in a large current, leading to increased copper losses and reduced efficiency of motor 1000. Conversely, a Di / Dout ratio that is too large indicates a large rotor assembly 100 with a small stator area. This reduces the area of ​​the winding slot 215, increasing copper losses. It also leads to a high magnetic load, high magnetic density, and high iron losses, further reducing the efficiency of motor 1000.

[0068] It should be noted that magnetic load refers to the average magnetic flux per unit area of ​​the air gap surface in motor 1000. Magnetic load affects the speed, torque, and power of motor 1000. Magnetic load is directly proportional to the number of turns and current of winding 220, and inversely proportional to the length of the coil. For example, when the magnetic load increases, the speed of motor 1000 usually decreases, while the torque increases; conversely, when the magnetic load decreases, the speed of motor 1000 increases, but the torque may decrease. Therefore, the relationship between the speed, torque, and power of motor 1000 can be balanced by changing the magnetic load.

[0069] Understandably, in order for the shaft 130 to drive the rotation of other components, it needs to possess a certain strength, meaning D0 cannot be too small. If the diameter D0 of the shaft 130 is too large, with Lm remaining constant, the gap between the shaft 130 and the permanent magnet 120 will be small. Subsequent sealing with encapsulating material in the gap can easily lead to poor connection stability between the permanent magnet 120, the rotor core 110, and the shaft 130. Alternatively, filling the gap with elastic material may result in insufficient material, leading to increased vibration and noise in the rotor assembly 100. Therefore, the diameter of the shaft 130 should not be too small or too large. Conversely, a larger Lm results in lower space utilization of the rotor core 110, meaning a smaller volume of the permanent magnet 120 and lower magnetic flux. A smaller Lm results in higher space utilization of the rotor core 110, a larger volume of the permanent magnet 120, and higher magnetic flux, but this also narrows the gap between the shaft 130 and the permanent magnet 120, leading to unstable connections. Therefore, D0 / Lm reflects the reciprocal of the placement rate of the permanent magnet 120. The smaller D0 / Lm is, the lower the space utilization and the smaller the magnetic flux; the larger D0 / Lm is, the higher the space utilization and the larger the magnetic flux, but this will result in insufficient space between the shaft 130 and the rotor core 110 to fill the connecting material, such as molding material or rubber. In one embodiment, D0 is 8 mm and Lm is 24.27 mm.

[0070] Therefore, (D0 / Lm)×(Di / Dout) reflects the impact on the size of the motor 1000 and the internal space utilization of the rotor assembly 100. When (D0 / Lm)×(Di / Dout) is less than 1 / 8, it indicates that the rotor assembly 100 is small, the magnetic load is small, and the current is large for the same output torque, leading to increased copper losses. Furthermore, the lower the space utilization, the smaller the magnetic flux. When (D0 / Lm)×(Di / Dout) is greater than 3 / 8, it indicates that the rotor assembly 100 is large, the stator area is small, leading to a reduction in the area of ​​the winding slot 215, increased copper losses, and a higher space utilization, resulting in a larger magnetic flux. However, this can lead to insufficient space between the shaft 130 and the rotor core 110 to fill the connection. By rationally designing the value of D0 / Lm×Di / Dout, it is possible to improve the space utilization of the rotor assembly 100 to increase the magnetic flux while ensuring a reduction in the iron and copper losses of the motor 1000, thereby improving the working efficiency and performance of the motor 1000.

[0071] Reference Figure 2 and Figure 5 As shown, in an embodiment of the present invention, along the circumferential direction of the rotating shaft 130, the width of the permanent magnet 120 is hpm, and the width of the tooth portion 213 is Wt, satisfying:

[0072]

[0073] For example, the value can be 0.2, 0.3, 0.5, 0.6, 0.7, 0.8, 0.9, etc. Among these, the larger the width hpm of the permanent magnet 120, the higher the air gap magnetic flux density, the closer it is to the remanence of the permanent magnet 120, the larger the equivalent air gap, the stronger the overload capacity, and the higher the magnetic flux density, but the iron loss also increases. The smaller the width hpm of the permanent magnet 120, the smaller the equivalent air gap, the lower the overload capacity, the lower the magnetic flux density, and the lower the iron loss. The larger the width Wt of the tooth 213, the stronger the overload capacity, but the smaller the area of ​​the winding 220, the higher the resistance, and the higher the copper loss. The smaller the width Wt of the tooth 213, the lower the overload capacity, the larger the area of ​​the winding 220, the lower the resistance, and the lower the copper loss. Therefore, hpm / Wt reflects the overload capacity and efficiency of the motor 1000.

[0074] When (hpm / Wt)×(Di / Dout) is less than 1 / 10, it indicates that the rotor assembly 100 is small, with a low magnetic load. Under the same output torque, the current is large, leading to increased copper losses. The motor 1000 has a low overload capacity and low iron losses, but high copper losses. When (hpm / Wt)×(Di / Dout) is greater than 1, it indicates that the rotor assembly 100 is large, with a small stator area. This results in a smaller winding slot area 215, increased copper losses, and the motor 1000 has a strong overload capacity, high iron losses, and low copper losses. Furthermore, hpm and Wt have opposite effects on overload capacity. Therefore, a reasonable design of (hpm / Wt)×(Di / Dout) can better balance the impact of iron and copper losses on the motor 1000, while also enabling the motor 1000 to have a higher overload capacity and improve its performance.

[0075] Reference Figure 2 , Figure 3 and Figure 5 As shown, in an embodiment of the present invention, the rotor core 110 includes a plurality of sector-shaped portions 111 arranged circumferentially along the rotating shaft 130, and a mounting groove 112 for mounting a permanent magnet 120 is formed between two adjacent sector-shaped portions 111. Along the circumferential direction of the rotating shaft 130, the maximum width of the sector-shaped portion 111 is Wr, and the maximum width of the tooth tip 214 is Wt0, satisfying:

[0076]

[0077] The aforementioned ratio can take values ​​such as 1 / 2, 5 / 8, 3 / 4, 7 / 8, 1, 1.5, etc. The maximum width Wr of the sector 111 reflects the magnetic circuit width on the rotor side, while Wt0 is the magnetic circuit width on the stator side. Therefore, Wr / Wt0 reflects the relationship between the width of the emitted magnetic flux and the width of the received magnetic flux. (Refer to...) Figure 6 As shown, Figure 6 The dashed arrows in the diagram indicate the direction of the magnetic flux path. The permanent magnet 120 is magnetized circumferentially along the shaft 130. Therefore, along the circumference of the shaft 130, the two sides of the permanent magnet 120 are the N pole and the S pole, respectively. The magnetic flux path starts from the N pole of the excitation source, enters the sector section 111, and then sequentially passes through the air gap, tooth tip 214, tooth section 213, yoke section 211, another adjacent tooth section 213, tooth tip 214, air gap, sector section 111, and finally returns to the S pole of the excitation source. Therefore, the magnetic flux enters the air gap from the rotor side (Wr) and then enters the stator side (Wt0). The magnetic circuit widths on the rotor side and the stator side usually need to be matched to efficiently utilize the magnetic field generated by the permanent magnet 120. When Wr / Wt0 is too large or too small, it will result in one side having a large magnetic circuit width and the other side having a small magnetic circuit width, causing waste of magnetic circuit space and reducing the efficiency of the motor 1000. In one embodiment, Wr is 8.28 mm and Wt0 is 9.86 mm.

[0078] In particular, a well-designed relationship between Wr and Wt0 can reduce cogging torque and pulsating torque. Cogging torque is generated by the interaction between the flux emitting surface and the flux receiving surface; Wr and Wt0 can be simply understood as the flux emitting surface and the flux receiving surface. When only the value of Wr / Wt0 is changed, the interaction between the flux emitting surface and the flux receiving surface causes an energy change, which in turn generates cogging torque.

[0079] When the size difference between the magnetic flux receiving surface and the magnetic flux emitting surface is large, when the magnetic flux emitting surface passes through a complete magnetic flux receiving surface, the single-tooth cogging torque waveform is incomplete. The cogging torque waveform formed by one stator tooth 212 and the other symmetrical stator tooth 212 is equal in magnitude and opposite in direction (the same is true for other opposite stator teeth 212), but they cannot completely cancel each other out. The cogging torques on all 18 stator teeth 212 are superimposed, resulting in larger cogging torque and pulsating torque.

[0080] To reduce cogging torque, the sizes of the flux receiving surface and the flux emitting surface are designed to be approximately equal. When the flux emitting surface passes through a complete flux receiving surface, the positive and negative half-cycles of the resulting cogging torque are symmetrical, forming a complete single-tooth cogging torque waveform (0→maximum→0→minimum→0). The number of cycles forming the cogging torque is equal to the number of slots. Ultimately, the cogging torque waveforms formed by one stator tooth 212 and the symmetrical stator tooth 212 are equal in magnitude and opposite in direction (the same applies to other opposing stator teeth 212), thus canceling each other out and minimizing the overall cogging torque and pulsating torque.

[0081] Therefore, (Wr / Wt0)×(Di / Dout) reflects the impact on the dimensions of motor 1000, the width of the magnetic circuit on the rotor side, and the width of the magnetic circuit on the stator side. When (Wr / Wt0)×(Di / Dout) is less than 3 / 8, it indicates that the rotor assembly 100 is very small, the magnetic load is small, and the current is large for the same output torque, leading to increased copper losses. Furthermore, the narrow width of the stator side magnetic circuit results in wasted magnetic circuit space, resulting in low efficiency of motor 1000 and large cogging torque and pulsating torque. When (Wr / Wt0)×(Di / Dout) is greater than 2, it indicates that the rotor assembly 100 is very large, the stator area is small, leading to a reduction in the area of ​​the winding slot 215, increased copper losses, and a narrow width of the rotor side magnetic circuit, resulting in wasted magnetic circuit space. This also leads to low efficiency of motor 1000 and large cogging torque and pulsating torque. Therefore, by rationally designing the size range of (Wr / Wt0)×(Di / Dout), the size relationship between the rotor-side magnetic circuit and the stator-side magnetic circuit can be balanced, the utilization rate of the magnetic circuit can be improved, and the cogging torque and torque pulsation of the motor 1000 can be reduced, thereby improving the efficiency of the motor 1000.

[0082] Reference Figure 3As shown, in an embodiment of the present invention, the maximum length of the sector portion 111 along the radial direction of the rotating shaft 130 is Lr, satisfying:

[0083]

[0084] The values ​​mentioned above can be 0.54, 0.6, 0.65, 0.7, 0.75, 0.8, 1, 1.2, 1.5, etc. It can be understood that Lr is the width of the emitted magnetic flux, and Wt0 is the width of the received magnetic flux. Therefore, Lr / Wt0 reflects the balance between the emitted and received magnetic flux widths. If Lr / Wt0 is too large or too small, it will result in one side of the magnetic circuit being wide and the other side being narrow, leading to low utilization of the magnetic circuit. In one embodiment, Lr is 15.95 mm and Wt0 is 9.86 mm.

[0085] Therefore, (Lr / Wt0)×(Di / Dout) reflects the impact on the size of the motor 1000, the width of the magnetic flux output, and the width of the magnetic flux reception. When (Lr / Wt0)×(Di / Dout) is less than 0.5, it indicates that the rotor assembly 100 is small, the magnetic load is small, and the current is large for the same output torque, leading to increased copper losses, a narrower magnetic flux output width, a wider magnetic flux reception width, low magnetic circuit utilization, and low magnetic flux quantity, making it difficult to improve the torque and speed of the motor 1000. When (Lr / Wt0)×(Di / Dout) is greater than 1.6, it indicates that the rotor assembly 100 is large, the stator area is small, resulting in a smaller area of ​​the winding slot 215, increased copper losses, a wider magnetic flux output width, but a narrower magnetic flux reception width, low magnetic circuit utilization, and difficulty in improving the torque and speed of the motor 1000. Therefore, by rationally designing the size of (Lr / Wt0)×(Di / Dout), the utilization rate of the magnetic circuit can be improved, the cogging torque of motor 1000 can be reduced, and the working efficiency of motor 1000 can be improved.

[0086] Reference Figure 4 As shown, in this embodiment of the invention, the maximum distance between the bottoms of the two winding grooves 215 arranged radially opposite each other along the rotating shaft 130 is Li. It should be noted that when the bottom of the winding groove 215 is not arc-shaped, the maximum distance Li between the bottoms of the two opposing winding grooves 215 refers to the diameter of the circumcircle of the two opposing groove bottoms. Along the axial direction of the rotating shaft 130, the height of the permanent magnet 120 is H, satisfying:

[0087]

[0088] The aforementioned ratio can take values ​​such as 0.44, 0.5, 0.6, 0.7, 0.8, 1, 1.25, 2, etc. It can be understood that (Li-Di) / 2 represents the radial depth of the winding groove 215 on the rotating shaft 130, indicating the amount of winding 220 that the winding groove 215 can accommodate. The greater the depth of the winding groove 215, the more copper wire can be wound in the winding 220, i.e., the greater the amount of copper used, resulting in lower copper loss; conversely, the smaller the depth of the winding groove 215, the fewer copper wires can be wound in the winding 220, i.e., the less copper used, and the greater the copper loss. In one embodiment, (Li-Di) / 2 can be 10.45 mm.

[0089] The height direction of the permanent magnet 120 is perpendicular to the direction of its magnetic flux area. That is, the larger the height H of the permanent magnet 120, the greater the quantity of permanent magnets 120 used, the greater the magnetic load, the higher the air gap magnetic density, and the greater the iron loss. Conversely, the smaller the height H of the permanent magnet 120, the fewer permanent magnets 120 used, the smaller the magnetic load, the lower the air gap magnetic density, and the smaller the iron loss. In one embodiment, the height H of the permanent magnet 120 is 11.5 mm.

[0090] When (Li-Di) / 2H is less than 0.25, both iron and copper losses are relatively high. When (Li-Di) / 2H is greater than 2.5, both iron and copper losses are relatively low, but the magnetic load is small, resulting in a decrease in the torque of the motor 1000. Furthermore, the depth of the winding slot 215 cannot be infinitely large; the volume of the motor 1000, the structural strength of the stator assembly 200 and the rotor assembly 100 must be considered. Therefore, by rationally designing the depth of the winding slot 215 and the height of the permanent magnet 120, the copper and iron losses of the motor 1000 can be reduced, thereby improving the overall efficiency of the motor 1000. Simultaneously, the magnetic load can be kept at an appropriate level to balance the torque and speed of the motor 1000.

[0091] Reference Figure 5 As shown, in an embodiment of the present invention, the width of the yoke 211 along the radial direction of the shaft 130 is Wy, where Wy refers to the distance between the outer side of the yoke 211 and the bottom of the winding groove 215. The width of the tooth 213 along the circumferential direction of the shaft 130 is Wt, satisfying:

[0092]

[0093] The aforementioned ratio can take values ​​such as 0.3, 0.5, 0.6, 0.7, 0.8, 0.9, 1.5, and 2. It is understandable that the width Wy of the yoke 211 and the width Wt of the tooth 213 jointly affect the area of ​​the winding slot 215 and the magnetic circuit width. The size of the winding slot 215 affects the volume accommodating the winding 220. If the area of ​​the winding slot 215 decreases, the volume accommodating the winding 220 decreases, leading to increased copper losses. That is, one value needs to be increased, while the other needs to be decreased to ensure the winding slot 215 has a suitable area. Simultaneously reducing the width Wy of the yoke 211 and the width Wt of the tooth 213 will result in a decreased magnetic circuit width, increased magnetic density, and increased iron losses. Furthermore, the yoke 211 and the tooth 213 also need to maintain a certain strength; that is, the width Wy of the yoke 211 and the width Wt of the tooth 213 cannot be too small. In one embodiment, Wt is 4.6 mm and Wy is 4.5 mm.

[0094] Therefore, Wy / Wt reflects the influence of the area of ​​the winding slot 215 and the width of the magnetic circuit on copper loss, iron loss and strength. If Wy / Wt is too small, the strength of the tooth 213 is insufficient and the width of the magnetic circuit is reduced, which will increase iron loss. If Wy / Wt is too large, the strength of the yoke 211 is insufficient, which will also lead to a reduction in the width of the magnetic circuit and an increase in iron loss.

[0095] The formula (Wy / Wt) × (Di / Dout) reflects the impact on the size of the motor 1000, copper losses, iron losses, and the strength of the stator core 210. When (Wy / Wt) × (Di / Dout) is less than 0.25, it indicates that the rotor assembly 100 is small, with a low magnetic load. Under the same output torque, the current is large, leading to increased copper losses, a narrow magnetic circuit width, and increased iron losses. Furthermore, the strength of the yoke 211 is insufficient, making it prone to deformation and bending. When (Wy / Wt) × (Di / Dout) is greater than 2.5, it indicates that the rotor assembly 100 is large, with a small stator area. This results in a smaller winding slot area 215, increased copper losses, a high magnetic load, high magnetic density, a narrow magnetic circuit width, and high iron losses. Therefore, by rationally designing the ratio of (Wy / Wt)×(Di / Dout), the strength of the yoke 211 and the tooth 213 can be guaranteed, while iron loss and copper loss can be balanced, so that the motor 1000 is in a better working state, improving the performance of the motor 1000, while ensuring that the size of the motor 1000 is not too large.

[0096] Reference Figure 3 As shown, in an embodiment of the present invention, the maximum length of the sector portion 111 along the radial direction of the rotation axis 130 is Lr, and the maximum width of the sector portion 111 along the circumferential direction of the rotation axis 130 is Wr, satisfying:

[0097]

[0098] The ratio mentioned above can take values ​​such as 0.7, 1, 1.1, 1.2, 1.3, 1.4, 2, 2.1, etc. It can be understood that Lr is the width of the magnetic flux output, and Wr is the width of the magnetic circuit on the rotor side. Lr / Wr reflects the balance between the magnetic circuit widths of the permanent magnet 120 and the rotor core 110. When the inner diameter of the stator core 210 is fixed, the outer diameter of the rotor core 110 is usually also fixed. When Lr increases, but Wr cannot increase synchronously, it needs to decrease; otherwise, the mounting slot 112 will be smaller, making it impossible to install the permanent magnet 120, or a smaller permanent magnet 120 may need to be replaced, but this would result in insufficient magnetic field strength and a decrease in the torque output of the motor 1000. Therefore, Wr needs to be reduced to accommodate the permanent magnet 120. When a larger permanent magnet 120 is required to increase the magnetic field strength, the Lr / Wr ratio needs to be designed appropriately to balance the width of the magnetic flux output and the width of the rotor-side magnetic circuit, thereby enabling more efficient utilization of the magnetic field generated by the permanent magnet 120. In one embodiment, Lr is 15.95 mm and Wr is 8.28 mm.

[0099] Therefore, (Lr / Wr)×(Di / Dout) reflects the impact on the size of the motor 1000, the width of the magnetic flux output, and the width of the rotor-side magnetic circuit. When (Lr / Wr)×(Di / Dout) is less than 0.6, the rotor assembly 100 is very small, the magnetic load is small, and the current is large for the same output torque, resulting in increased copper losses. Furthermore, with a smaller Lr and a larger Wr, the radial length of the mounting slot 112 decreases, and the circumferential width of the shaft 130 also decreases, which reduces the volume of the permanent magnet 120 that the mounting slot 112 can accommodate, leading to a decrease in magnetic field strength. When (Lr / Wr)×(Di / Dout) is greater than 2.5, the rotor assembly 100 is very large, and the stator area is small, resulting in a smaller area of ​​the winding slot 215, increased copper losses, and also a large magnetic load, high magnetic density, and high iron losses. Furthermore, a larger Lr and a smaller Wr increase the radial length of the mounting slot 112 and its circumferential width on the shaft 130, increasing the volume of the permanent magnet 120 that the mounting slot 112 can accommodate and increasing the magnetic field strength. However, it is difficult to balance the width of the magnetic flux emitted by the rotor core 110 with the width of the rotor-side magnetic circuit. Therefore, a reasonable design of the value of (Lr / Wr)×(Di / Dout) can balance the width of the magnetic flux emitted by the rotor core 110 and the width of the rotor-side magnetic circuit, making more efficient use of the magnetic field generated by the permanent magnet 120, reducing copper and iron losses, and improving the working efficiency of the motor 1000.

[0100] Reference Figure 2 and Figure 4As shown in the embodiment of the present invention, the rotor core 110 further includes a bushing 140, which is sleeved on the rotating shaft 130 and located between the rotating shaft 130 and the rotor core 110. A plurality of second protrusions 141 are spaced apart on the side of the bearing facing away from the rotating shaft 130. These second protrusions 141 are spaced apart from the rotor core 110 and protrude towards it. The multiple second protrusions 141 are spaced apart circumferentially along the rotating shaft 130. Since a plastic sealant or elastic material needs to be provided between the bushing 140 and the rotor core 110 to connect them, taking the use of a plastic sealant as an example, the second protrusions 141 can increase the contact area with the sealant, making the connection between the bushing 140 and the rotor core 110 more stable and improving the torque transmitted by the rotating shaft 130 and the rotor core 110. The number of second protrusions 141 is N0. In one embodiment, the number of second protrusions 141, N0, is 7. Of course, it can also be other numbers, such as 2, 6, 8, 9, 14, etc., and the appropriate number should be selected according to the actual situation. The number of stator teeth 212 is Nr, which satisfies:

[0101]

[0102] The values ​​of the above ratios can be 0.17, 0.22, 0.28, 0.33, 0.39, 0.44, etc. Since the number of winding slots 215 in the stator core 210 is fixed at 18, and a winding slot 215 is formed between two adjacent stator teeth 212, the number of stator teeth 212 is the same as the number of winding slots 215, that is, the number of stator teeth 212 is also 18.

[0103] When N0 / Nr is less than 0.11, meaning the number of second protrusions 141 (N0) is too small, it leads to uneven torque transmission and increases connection stability. When N0 / Nr is greater than 0.78, the number of second protrusions 141 (N0) is too large. Since the bushing 140 and the second protrusion 141 are usually an integral structure made of magnetically conductive material, according to the principle of minimum magnetic reluctance, magnetic field lines always choose the path of least magnetic reluctance. Therefore, a large number of second protrusions 141 easily leads to increased magnetic leakage, increased losses in the motor 1000, reduced torque and output power of the motor 1000, and thus reduced efficiency. Therefore, by rationally selecting the number of stator teeth 212 and the number of second protrusions 141, the torque transmitted between the shaft 130 and the rotor core 110 can be increased, balancing the copper loss, iron loss, and winding coefficient of the motor 1000, thereby improving the overall efficiency of the motor 1000.

[0104] Reference Figure 5As shown, in an embodiment of the present invention, a second slot 216 is formed between adjacent tooth tips 214 along the circumferential direction of the rotating shaft 130. The second slot 216 communicates with the winding groove 215, and the width of the second slot 216 is So. The width of the tooth portion 213 along the circumferential direction of the rotating shaft 130 is Wt, satisfying:

[0105]

[0106] The aforementioned ratios can take values ​​such as 0.15, 0.2, 0.25, 0.3, 0.35, and 0.4. It is understandable that a larger width So of the second slot 216 results in lower magnetic leakage, but a smaller magnetic flux receiving area at the tooth tip 214. Conversely, a smaller width So results in higher magnetic leakage, but an increased magnetic flux receiving area at the tooth tip 214. The magnitude of Wt affects parameters such as magnetic density and copper loss. Magnetic density, also known as magnetic induction intensity, represents the number of magnetic field lines perpendicularly passing through a unit area. A wider Wt results in a wider magnetic circuit, lower magnetic density in the stator core 210, and reduced iron loss; however, a smaller area in the winding slot 215 leads to increased resistance in the winding 220 and increased copper loss. A narrower Wt results in a narrower magnetic circuit, higher magnetic density in the stator core 210, and increased iron loss; while a larger area in the winding slot 215 leads to decreased resistance in the winding 220 and reduced copper loss. Therefore, Wt cannot be too wide or too narrow. While considering the strength of the tooth 213, it is also necessary to balance the copper and iron losses. In one embodiment, the width So of the second slot 216 is 0.72 mm, and the width Wt of the tooth 213 is 4.6 mm.

[0107] Therefore, So / Wt reflects the relationship between the magnetic flux receiving area and the magnetic circuit width. If So / Wt is too small, although the magnetic flux receiving area and the magnetic circuit width increase and the iron loss decreases, the leakage flux increases and the copper loss increases. If So / Wt is too large, although the leakage flux decreases and the copper loss decreases, the magnetic flux receiving area and the magnetic circuit width decrease and the iron loss increases.

[0108] Here, (So / Wt)×(Di / Dout) reflects the impact on the size of the motor 1000, the magnetic flux receiving area, and the magnetic circuit width. When (So / Wt)×(Di / Dout) equals 0, the width So of the second slot 216 is 0, meaning there is no second slot 216. The rotor assembly 100 is very small, the magnetic load is small, and under the same output torque, the current is large, leading to increased copper losses, increased magnetic flux receiving area and magnetic circuit width, and decreased iron losses. However, leakage flux increases, and the efficiency of the motor 1000 decreases. When (So / Wt)×(Di / Dout) is greater than 0.44, the rotor assembly 100 is very large, the stator area is small, leading to a decrease in the area of ​​the winding slot 215, increased copper losses, and also a large magnetic load, high magnetic density, high iron losses. The magnetic flux receiving area and magnetic circuit width decrease, and the efficiency of the motor 1000 also decreases. Therefore, by rationally designing the ratio of (So / Wt)×(Di / Dout), it is possible to balance the magnetic load, magnetic density, copper loss and iron loss, reduce magnetic circuit waste, and maximize the magnetic flux receiving area and magnetic circuit width. This can increase the magnetic flux of each magnetic pole, thereby increasing the torque of motor 1000 and also increasing the speed of motor 1000.

[0109] Reference Figure 2 As shown, in an embodiment of the present invention, a first protrusion 113 is formed on the side of the fan-shaped portion 111 away from the rotating shaft 130 and facing the mounting groove 112. The first protrusion 113 is used to abut against the side of the permanent magnet 120 away from the rotating shaft 130, thereby preventing the permanent magnet 120 from being dislodged from the mounting groove 112 by centrifugal force when the rotor rotates. Therefore, the first protrusion 113 serves to limit the position of the permanent magnet 120. A first slot 114 is formed between the first protrusions 113 on both sides of the mounting groove, and the width of the first slot 114 is Sor. (Refer to...) Figure 4 As shown, the maximum outer diameter of the stator core 210 is Dout, and the minimum inner diameter is Di. It should be noted that when the outer and inner sides of the stator core 210 are not circular, the maximum outer diameter refers to the diameter of the circumscribed circle of the stator core 210, and the minimum inner diameter refers to the diameter of the inscribed circle of the stator core 210. Satisfying:

[0110]

[0111] The aforementioned ratios can take values ​​such as 0.15, 0.2, 0.25, 0.3, 0.4, 0.5, and 0.8. A larger width Sor of the first slot 114 results in lower magnetic leakage and higher magnetic flux; a smaller width Sor results in higher magnetic leakage and lower magnetic flux. Furthermore, the width of the first slot 114 is related to the size of the first protrusion 113. The first protrusion 113 needs to restrict the permanent magnet 120 from detaching from the mounting slot 112. Therefore, the width of the first slot 114 cannot be too large or too small, thus restricting the permanent magnet 120 from detaching from the mounting slot 112 while also reducing magnetic leakage and increasing magnetic flux. A larger width So of the second slot 216 results in lower magnetic leakage, but the magnetic flux receiving area of ​​the tooth tip 214 will decrease. A smaller width So of the second slot 216 results in higher magnetic leakage, but the magnetic flux receiving area of ​​the tooth tip 214 will increase. In one embodiment, the width So of the first slot 114 is 3.82 mm, and the width So of the second slot 216 is 0.72 mm.

[0112] Therefore, So / Sor reflects the magnitude of magnetic leakage and the relationship between the amount of magnetic flux emitted and received. If So / Sor is too small, the amount of magnetic leakage is large; if So / Sor is too large, the amount of magnetic flux is small and the magnetic flux receiving area is small.

[0113] When (So / Sor) × (Di / Dout) equals 0, the width So of the second slot 216 is 0, meaning the second slot 216 does not exist. This results in a small rotor assembly 100, low magnetic load, increased copper losses, and high leakage flux. When (So / Sor) × (Di / Dout) is greater than 0.63, the rotor assembly 100 is large, the stator area is small, the winding slot 215 area is small, copper losses increase, magnetic load is high, iron losses are high, magnetic flux is low, and the magnetic flux receiving area is small. Therefore, under the condition of 18 slots and 14 poles, by limiting the value of So / Sor*Di / Dout between 0.05 and 0.63, the size of the motor 1000 is kept appropriate to further reduce copper and iron losses, decrease leakage flux, increase magnetic flux, balance the relationship between magnetic flux emission and magnetic flux receiving area, further improve the efficiency and performance of the motor 1000, and put the motor 1000 in an optimal working state.

[0114] Reference Figure 10 As shown, in an embodiment of the present invention, the rotor core 110 includes a bushing 140 circumferentially arranged around the rotating shaft 130. The bushing 140 is connected to the rotating shaft 130, and the sector-shaped portion 111 is connected to the bushing 140 via a connecting bridge 142. For example, all the sector-shaped portions 111 can be connected to the bushing 140 via connecting bridges 142, thereby determining the relative position between the sector-shaped portions 111 and the bushing 140, facilitating subsequent plastic coating processing. Or refer to... Figure 11As shown, in another embodiment, some of the sector sections 111 may be connected to the bushing 140 via a connecting bridge 142. For example, along the circumference of the rotating shaft 130, one of every two adjacent sector sections 111 may be connected to the bushing 140 via a connecting bridge 142, while the other may be spaced apart from the bushing 140. It is understood that when only some of the sector sections 111 are connected to the bushing 140 via a connecting bridge 142, magnetic leakage can be reduced, improving the working efficiency of the motor 1000. In another embodiment of the present invention, the bushing 140 may also be spaced apart from multiple sector sections 111, meaning that neither the sector section 111 nor the bushing 140 is connected by a connecting bridge 142, which can further reduce magnetic leakage. A suitable solution can be selected based on the specific circumstances.

[0115] In embodiments of the present invention, the stator core 210 can be manufactured by means of straight bars, blocks, and tooth yoke separation, which can improve the slot fill factor of the winding slot 215 and improve the material utilization rate of the stator core 210.

[0116] One embodiment of the present invention provides a household appliance including the motor 1000 described in the above embodiments. It is understood that the motor 1000 of this embodiment can be used in household appliances such as electric fans, air conditioners, dehumidifiers, refrigerators, and washing machines. As a core component of the household appliance, the motor 1000 drives components such as impellers, drums, or rollers to rotate, thereby realizing the function of the household appliance.

[0117] The household appliance of this invention adopts the motor 1000 of the first aspect embodiment. By setting the number of winding slots 215 of the stator core 210 of the stator assembly 200 to 18 and the number of permanent magnets 120 of the rotor assembly 100 to 14, that is, the motor 1000 is an 18-slot, 14-pole motor 1000, the relationship between the copper loss, iron loss and winding coefficient of the motor 1000 can be optimized, thereby reducing the copper loss and iron loss while increasing the winding coefficient, thereby improving the efficiency of the motor 1000. The Di / Dout ratio affects the size, iron loss, magnetic load, and efficiency of motor 1000. A Di / Dout ratio that is too small indicates a small rotor assembly 100 with a low magnetic load. For the same output torque, this results in a large current, leading to increased copper losses and reduced efficiency of motor 1000. Conversely, a Di / Dout ratio that is too large indicates a large rotor assembly 100 with a small stator area. This reduces the area of ​​the winding slot 215. With the number of turns in winding 220 remaining constant, the diameter of the copper wire in winding 220 needs to be reduced, leading to increased resistance and thus increased copper losses. This also results in a high magnetic load, high magnetic density, and high iron losses, further reducing the efficiency of motor 1000. D0 is the diameter of the shaft 130, and Lm is the distance between the two relatively positioned permanent magnets 120. Lm reflects the space utilization rate of the rotor core 110. A larger Lm indicates that a significant portion of the space in the rotor core 110 is not used to install the permanent magnets 120. Therefore, D0 / Lm reflects the reciprocal of the placement rate of the permanent magnet 120. The smaller D0 / Lm is, the lower the space utilization and the smaller the magnetic flux; the larger D0 / Lm is, the higher the space utilization and the larger the magnetic flux, but this will result in insufficient space between the shaft 130 and the rotor core 110 to fill the connecting material, such as plastic sealing material or rubber. Under the condition of 18 slots and 14 poles, by limiting the value of D0 / Lm×Di / Dout to between 1 / 8 and 3 / 8, the magnetic flux can be increased while ensuring the iron loss and working efficiency of the balanced motor 1000, thereby improving the performance of the motor 1000.

[0118] Since the household appliance of this invention adopts all the technical solutions of the motor 1000 of the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be repeated here.

[0119] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. An electric machine characterized in that, include: The rotor assembly includes a rotor core, a plurality of permanent magnets and a rotating shaft. The rotating shaft is connected to the inner side of the rotor core. The rotor core is provided with a plurality of mounting slots arranged circumferentially along the rotating shaft. The plurality of permanent magnets are correspondingly mounted in the plurality of mounting slots. A stator assembly is wound around the outside of the rotor assembly. The stator assembly includes a stator core, which has a plurality of winding slots arranged circumferentially along the shaft. The number of winding slots is 18, and the number of permanent magnets is 14; the maximum outer diameter of the stator core is Dout, the minimum inner diameter of the stator core is Di, the maximum diameter of the rotating shaft is D0, and the distance between two permanent magnets arranged radially opposite each other along the rotating shaft is Lm, satisfying the following:

2. The electric machine of claim 1, wherein: The width of the permanent magnet is hpm, and the stator core includes teeth with a width of Wt, satisfying the following:

3. The electric machine of claim 1, wherein: The rotor core includes a plurality of sector-shaped portions arranged circumferentially along the rotating shaft, with mounting grooves formed between adjacent sector-shaped portions. The maximum width of each sector-shaped portion along the circumferential direction of the rotating shaft is Wr. The stator core includes tooth tips with a maximum width of Wt0, satisfying the following:

4. The motor according to claim 1, characterized in that: The rotor core includes a plurality of sector-shaped portions arranged circumferentially along the rotating shaft. The maximum length of each sector-shaped portion is Lr along the radial direction of the rotating shaft. The stator core includes tooth tips with a maximum width Wt0, satisfying the following:

5. The motor according to claim 1, characterized in that: The maximum distance between the bottoms of the two winding slots arranged radially opposite each other along the rotating shaft is Li, and the height of the permanent magnet along the axial direction of the rotating shaft is H, satisfying:

6. The motor according to claim 1, characterized in that: The stator core includes a yoke and a plurality of stator teeth. The stator teeth are circumferentially spaced along the axis of rotation on the inner side of the yoke. The width of the yoke is Wy along the radial direction of the axis of rotation. Each stator tooth includes a tooth portion and a tooth tip. The tooth portion is connected to the yoke, and the tooth tip is connected to the side of the tooth portion away from the yoke. The width of the tooth portion is Wt, satisfying:

7. The motor according to claim 1, characterized in that: The rotor core includes a plurality of sector-shaped portions arranged circumferentially along the rotating shaft. The maximum width of each sector-shaped portion along the circumferential direction of the rotating shaft is Wr, and the maximum length of each sector-shaped portion along the radial direction of the rotating shaft is Lr, satisfying the following:

8. The motor according to claim 1, characterized in that: The rotor core includes a bushing arranged circumferentially around the rotating shaft, and a plurality of sector-shaped portions arranged circumferentially at intervals along the rotating shaft. The bushing is connected to the rotating shaft, and some of the sector-shaped portions are connected to the bushing via connecting bridges.

9. The motor according to claim 1, characterized in that: The rotor core includes a bushing arranged circumferentially around the rotating shaft, and a plurality of sector-shaped portions arranged circumferentially at intervals along the rotating shaft, the bushing being spaced apart from the plurality of sector-shaped portions.

10. A household appliance, characterized in that: Includes the motor as described in any one of claims 1 to 9.

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