Motor and electric toothbrush with same

Abstract

The utility model discloses a motor and an electric toothbrush with the same, and the motor comprises a rotor assembly which comprises a rotor iron core and a coil, and the coil is arranged on the peripheral surface of the rotor iron core; the stator assembly is arranged on the rotor assembly in a sleeving mode, the rotor assembly can rotate relative to the stator assembly, and the stator assembly comprises a stator iron core and a permanent magnet; in the axial direction of the motor, the length of the permanent magnet is larger than that of the rotor core, and the two ends of the rotor core do not exceed the two ends of the permanent magnet. According to the motor, the magnetic field intensity of the permanent magnet and the mutual acting force of the permanent magnet and the coil can be increased, so that the purpose of increasing the power output of the motor is achieved.

Description

Technical Field

[0001] The present application relates to the technical field of motor equipment, and in particular to a motor and an electric toothbrush having the same. Background Art

[0002] The motor includes a stator and a rotor. The stator includes a permanent magnet, and the rotor includes a rotor core and a coil. The coil is wound around the rotor core. The magnetic field of the permanent magnet and the magnetic field of the coil after power is applied interact with each other to drive the rotor to rotate relative to the stator.

[0003] In the motor in the related technology, the length of the rotor core is consistent with the length of the permanent magnet. Under the influence of the machining error of the rotor core, the machining error of the permanent magnet and the assembly error, the length of the rotor core and the length of the permanent magnet cannot be kept consistent, resulting in low utilization of the permanent magnet and the coil, affecting the power output of the motor. Utility Model Content

[0004] The purpose of the present application is to provide a motor that can increase the magnetic field strength of the permanent magnet and the mutual force between the permanent magnet and the coil, thereby achieving the purpose of increasing the power output of the motor.

[0005] In order to achieve the above-mentioned objectives, the first aspect embodiment of the present application provides a motor, including a rotor assembly and a stator assembly, the rotor assembly including a rotor core and a coil, the coil being arranged on the outer circumferential surface of the rotor core; the stator assembly is sleeved on the rotor assembly, the rotor assembly is rotatable relative to the stator assembly, the stator assembly includes a stator core and a permanent magnet; wherein, in the axial direction of the motor, the length of the permanent magnet is greater than the length of the rotor core, and the two ends of the rotor core do not exceed the two ends of the permanent magnet.

[0006] In some embodiments of the present application, in the axial direction of the motor, two ends of the permanent magnet extend beyond two ends of the rotor core.

[0007] In some embodiments of the present application, in the axial direction of the motor, an end of the permanent magnet is located between an end of the coil and an end of the rotor core.

[0008] In some embodiments of the present application, in the axial direction of the motor, the dimension of the end of the permanent magnet exceeding the end of the rotor core is L1, 3mm≥L1≥0.5mm.

[0009] In some embodiments of the present application, the stator core includes: a stator shell; a yoke, wherein the yoke is located in the stator shell, and an inner circumferential surface of the yoke is provided with a mounting groove, wherein the mounting groove penetrates the yoke along the axial direction of the motor, and the permanent magnet is installed in the mounting groove; wherein, in the axial direction of the motor, the end of the permanent magnet is flush with the end of the yoke, or the end of the permanent magnet exceeds the end of the yoke.

[0010] In some embodiments of the present application, the stator core includes: a stator shell, the stator shell having a first end and a second end, the first end of the stator shell being provided with an opening, and the inner circumferential surface of the stator shell being provided with a limiting portion; a yoke, the yoke being located in the stator shell, the inner circumferential surface of the yoke being provided with a mounting groove, the mounting groove passing through the yoke along the axial direction of the motor, the permanent magnet being installed in the mounting groove, and the end of the yoke facing away from the opening being stopped at the limiting portion.

[0011] In some embodiments of the present application, the limiting portion is formed by an inward protrusion of the stator shell.

[0012] In some embodiments of the present application, the limiting portion and the permanent magnet are spaced apart in the circumferential direction of the motor.

[0013] In some embodiments of the present application, in the radial direction of the motor, the size of the limit portion is H1; the wall thickness of the abutment portion between the yoke and the limit portion is H2; wherein the ratio of H1 to H2 is greater than 1 / 2.

[0014] In some embodiments of the present application, the motor further includes: an end cover, the end cover including an insertion portion and a covering portion, the insertion portion being inserted into the stator shell, the covering portion being stopped at the end portion of the first end of the stator shell and covering the opening; wherein the interval between the insertion portion and the yoke is not less than 1 mm.

[0015] In some embodiments of the present application, a distance between an end of the permanent magnet facing away from the opening and the second end of the stator housing is not less than 3 mm and not more than 4.5 mm.

[0016] In some embodiments of the present application, the stator core includes two mounting side walls arranged opposite to each other in a first radial direction, each mounting side wall is provided with two permanent magnets; the rotor core includes a connecting part, two coil mounting parts and two positioning parts, the connecting part is used for transmission connection with the motor shaft, the two coil mounting parts are arranged on opposite sides of the connecting part in the first radial direction, and the positioning part is connected to the side of each coil mounting part facing away from the connecting part; wherein, the coil is arranged on the coil mounting part.

[0017] In some embodiments of the present application, a side of the positioning portion facing away from the coil mounting portion is constructed as an outwardly protruding arc-shaped surface; wherein, in the circumferential direction of the motor, the size of the inner circumferential surface of the permanent magnet is W1, the size of the arc-shaped surface is W2, and the ratio of W1 to W2 is greater than 1 / 2.

[0018] In some embodiments of the present application, the positioning portion extends beyond the coil in a second radial direction, and the first radial direction and the second radial direction are perpendicular to each other.

[0019] In some embodiments of the present application, the length of the permanent magnet is not less than 30 mm and not more than 40 mm.

[0020] The second aspect of the present application provides an electric toothbrush, comprising a handle shell and a movement, wherein the movement comprises the motor according to the first aspect of the present application, and the movement is installed in the handle shell.

[0021] The motor of the embodiment of the present application does not need to change the shape and size of the motor. By increasing the length of the permanent magnet, not only the magnetic field strength of the permanent magnet is increased, but also the mutual force between the permanent magnet and the coil is increased, and the output power of the motor is higher. Moreover, the length of the permanent magnet is greater than the length of the rotor core. Even if there are manufacturing errors and assembly errors, it can effectively ensure that the end of the rotor core will not exceed the end of the permanent magnet, and the end of the coil is closer to the permanent magnet in the axial direction of the motor. The permanent magnet can interact with the end of the coil more reliably, eliminating the power attenuation problem of the motor caused by the manufacturing error and the assembly error, improving the utilization rate of the coil end, and increasing the torque output of the motor. In other words, by increasing the length of the permanent magnet, the power output of the motor is increased from two dimensions: the magnetic field strength of the permanent magnet and the mutual force between the permanent magnet and the coil. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0023] Figure 1 A schematic diagram of the structure of a motor according to an embodiment of the present application;

[0024] Figure 2 An exploded diagram of a motor according to an embodiment of the present application;

[0025] Figure 3 A cross-sectional view of a motor according to an embodiment of the present application;

[0026] Figure 4 A cross-sectional view of a rotor assembly and a stator assembly of a motor according to an embodiment of the present application;

[0027] Figure 5 for Figure 4 A partial enlarged view of the middle A area;

[0028] Figure 6 for Figure 4 A partial enlarged view of the middle B area;

[0029] Figure 7 A cross-sectional view of the motor from another perspective of an embodiment of the present application;

[0030] Figure 8 A cross-sectional view of a stator core of a motor according to an embodiment of the present application;

[0031] Fig. 9 This is a schematic structural diagram of an end cover of a motor according to an embodiment of the present application;

[0032] Fig.10 A schematic diagram of the structure of a stator assembly of a motor according to an embodiment of the present application;

[0033] Fig.11 A schematic diagram of the structure of a rotor assembly of a motor according to an embodiment of the present application;

[0034] Fig.12 It is a schematic structural diagram of the rotor core of the rotor assembly of the motor according to an embodiment of the present application.

[0035] Description of Figure Numbers:

[0036] Motor 1,

[0037] The rotor assembly 100, the coil 110, the rotor core 120, the connecting portion 121, the coil mounting portion 122, the positioning portion 123,

[0038] stator assembly 200, yoke 210, mounting groove 211, permanent magnet 220, mounting side wall 230, stator core 240, stator housing 250, first end 251, second end 252, stopper 253, opening 254,

[0039] Shaft 300,

[0040] End cap 400 , insertion portion 410 , and cover portion 420 .

[0041] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0042] In order to make the objectives, technical solutions and advantages of the present application clearer, the following part will further describe the embodiments of the present application in detail in conjunction with the accompanying drawings.

[0043] When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present application. Instead, they are only examples of devices and methods consistent with some aspects of the present application as detailed in the attached claims.

[0044] In the description of the present application, it should be understood that the terms "first", "second", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances. In addition, in the description of the present application, unless otherwise specified, "multiple" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the objects associated before and after are in an "or" relationship.

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used in this specification are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0046] The electric toothbrush of the embodiment of the present application comprises a brush head, a handle shell and a movement, wherein the movement comprises a motor 1 described below in the present application, and the movement is arranged in the handle shell. The handle shell is used to be held by the user, and the brush head is connected to the rotating shaft 300 of the motor 1, and the rotating shaft 300 drives the brush head to move to clean the user's oral cavity.

[0047] The motor 1 according to the embodiment of the present application is described below with reference to the accompanying drawings.

[0048] like Figure 1-Figure 4 As shown, the motor 1 of the embodiment of the present application includes a rotor assembly 100 and a stator assembly 200. The motor 1 can be applied to an electric toothbrush, and the motor 1 can be a sonic motor 1.

[0049] The rotor assembly 100 includes a rotor core 120 and a coil 110, and the coil 110 is arranged on the outer circumference of the rotor core 120. The stator assembly 200 is sleeved on the rotor assembly 100, and the rotor assembly 100 is rotatable relative to the stator assembly 200. The rotor assembly 100 and the stator assembly 200 can be arranged coaxially, and the coil 110 will generate a magnetic field when energized. The motor 1 also includes a rotating shaft 300, which is transmission-connected to the rotor core 120. When the rotor assembly 100 rotates relative to the stator assembly 200, the power of the rotor assembly 100 is output through the rotating shaft 300.

[0050] The stator assembly 200 includes a stator core 240 and a permanent magnet 220. The permanent magnet 220 is used to generate a magnetic field. The magnetic field of the permanent magnet 220 interacts with the magnetic field of the coil 110 to drive the rotor assembly 100 to rotate relative to the stator assembly 200. The rotor core 120, the coil 110 and the permanent magnet 220 are all installed in the stator core 240. The stator core 240 can protect and position the rotor core 120, the coil 110 and the permanent magnet 220.

[0051] In the axial direction of the motor 1, the length of the permanent magnet 220 is greater than the length of the rotor core 120, and the two ends of the rotor core 120 do not exceed the two ends of the permanent magnet 220. In other words, both ends of the permanent magnet 220 exceed both ends of the rotor core 120, or one end of the permanent magnet 220 is out of one end of the rotor core 120, and the other end of the permanent magnet 220 is flush with the other end of the rotor core 120.

[0052] By increasing the length of the permanent magnet 220, there is no need to change the shape and size of the motor 1. Not only is the magnetic field strength of the permanent magnet 220 increased, thereby increasing the mutual force between the permanent magnet 220 and the coil 110, and increasing the output power of the motor 1, but also the length of the permanent magnet 220 is greater than the length of the rotor core 120. Even if there are manufacturing errors and assembly errors, it can effectively ensure that the end of the rotor core 120 will not exceed the end of the permanent magnet 220, and the distance between the end of the coil 110 and the permanent magnet 220 in the axial direction of the motor 1 is smaller. The permanent magnet 220 can more reliably interact with the end of the coil 110, eliminating the power attenuation problem of the motor 1 caused by the manufacturing error and the assembly error, improving the utilization rate of the end of the coil 110, and increasing the torque output by the motor 1.

[0053] That is, by increasing the length of the permanent magnet 220 , the power output of the motor 1 is increased from two dimensions: the magnetic field strength of the permanent magnet 220 and the mutual force between the permanent magnet 220 and the coil 110 .

[0054] In this way, the motor 1 according to the embodiment of the present application can increase the magnetic field strength of the permanent magnet 220 and the mutual force between the permanent magnet 220 and the coil 110, thereby achieving the purpose of increasing the power output of the motor 1.

[0055] According to the electric toothbrush of the embodiment of the present application, the motor 1 is connected to the brush head of the electric toothbrush, and the power of the motor 1 is transmitted through the brush head, so that the cleaning efficiency of the brush head is higher.

[0056] like Figure 4-Figure 6 As shown, in the axial direction of the motor 1, both ends of the permanent magnet 220 exceed both ends of the rotor core 120. In this way, each end of the permanent magnet 220 exceeds the end of the rotor core 120, and each end of the permanent magnet 220 has sufficient margin to absorb processing errors and assembly errors, so that the utilization rate of both ends of the coil 110 can be effectively improved, further increasing the torque output by the motor 1.

[0057] like Figure 4-Figure 6 As shown, in the axial direction of the motor 1 , the end of the permanent magnet 220 is located between the end of the coil 110 and the end of the rotor core 120 .

[0058] In this way, the end of the coil 110 exceeds the end of the permanent magnet 220, and the length of the permanent magnet 220 is less than the length of the coil 110. While ensuring the utilization of the end of the coil 110, the length of the permanent magnet 220 will not be too long, thereby reducing the cost of the permanent magnet 220 and taking into account the utilization of the coil 110, the utilization of the permanent magnet 220 and the production cost.

[0059] like Figure 5 and Figure 6 As shown, in the axial direction of the motor 1, the end of the permanent magnet 220 exceeds the end of the rotor core 120 by a dimension L1, 3mm≥L1≥0.5mm. For example, L1 may be 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm or 3mm.

[0060] When L1 is less than 0.5 mm, the end of the permanent magnet 220 is too small beyond the end of the rotor core 120, and the space in the motor 1 is not fully utilized. On the one hand, there is still room for improvement in the magnetic field of the permanent magnet 220, and on the other hand, the relative size between the coil 110 and the permanent magnet 220 in the axial direction of the motor 1 is small, and the magnetic field of the coil 110 cannot be fully utilized.

[0061] When L1>3mm, the end of the permanent magnet 220 exceeds the end of the rotor core 120 by too much. On the one hand, the permanent magnet 220 is too long, which may easily cause the permanent magnet 220 to break and be damaged. On the other hand, the cost of the permanent magnet 220 is high, and the magnetic field utilization rate of the coil 110 is improved little, resulting in a low cost-performance ratio.

[0062] By setting L1 to be greater than or equal to 0.5 mm and less than or equal to 3 mm, the relative size between the permanent magnet 220 and the coil 110 in the axial direction of the motor 1 is larger, the magnetic field utilization rate of the coil 110 is higher, and the cost of the permanent magnet 220 is not too high, the cost performance is high, and the permanent magnet 220 is not easy to break or damage.

[0063] like Figure 7 , Figure 8 and Fig.10 As shown, the stator core 240 includes a stator shell 250 and a yoke 210 . The yoke 210 is located in the stator shell 250 . An inner circumferential surface of the yoke 210 is provided with a mounting groove 211 . The mounting groove 211 penetrates the yoke 210 along the axial direction of the motor 1 . The permanent magnet 220 is mounted in the mounting groove 211 .

[0064] For example, the yoke 210 can be made of a soft magnetic material that does not generate a magnetic field (i.e., magnetic lines of force) and only transmits magnetic lines of force in the magnetic circuit. For example, the yoke 210 can be made of soft iron, A3 steel, or a soft magnetic alloy with relatively high magnetic permeability. The permanent magnet 220 refers to a magnet that can maintain its magnetism for a long time. The permanent magnet 220 can be made of artificial magnetic steel (iron-nickel-cobalt magnetic steel, etc.) or magnets.

[0065] In addition, the stator housing 250 is used to protect the stator assembly 200 and the rotor assembly 100. The yoke 210, the permanent magnet 220 and the rotor assembly 100 are placed in the stator housing 250 through the opening 254, or are taken out from the stator housing 250. The inner surface of the yoke 210 is provided with a mounting groove 211, and the permanent magnet 220 is arranged in the mounting groove 211. By providing the mounting groove 211 on the inner surface of the yoke 210 and installing the permanent magnet 220 in the mounting groove 211, the positioning between the permanent magnet 220 and the yoke 210 can be achieved, and the distance between the permanent magnet 220 and the rotor assembly 100 is relatively close, and the rotor assembly 100 is more significantly affected by the magnetic field of the permanent magnet 220, thereby ensuring the magnetic field utilization rate of the permanent magnet 220. In addition, the magnetic lines of force generated by the permanent magnet 220 can be transmitted through the yoke 210, avoiding magnetic leakage and improving the magnetic field utilization rate of the permanent magnet 220.

[0066] like Figure 4-Figure 6 As shown, in the axial direction of the motor 1, the end of the permanent magnet 220 is flush with the end of the yoke 210, or the end of the permanent magnet 220 exceeds the end of the yoke 210. In other words, both ends of the permanent magnet 220 exceed both ends of the yoke 210, or both ends of the permanent magnet 220 are flush with both ends of the yoke 210, or one end of the permanent magnet 220 exceeds one end of the yoke 210, and the other end of the permanent magnet 220 is flush with the other end of the yoke 210.

[0067] In this way, the magnetic circuit at the end of the permanent magnet 220 is less affected by the end of the yoke 210 , which is beneficial to improving the utilization rate of the magnetic field of the end cover 400 of the permanent magnet 220 , thereby improving the output power of the motor 1 .

[0068] like Figure 2 , Figure 3 , Figure 5 and Fig.10 As shown, the stator core 240 includes a stator shell 250 and a yoke 210. The stator shell 250 has a first end 251 and a second end 252. The first end 251 of the stator shell 250 is provided with an opening 254. The inner circumference of the stator shell 250 is provided with a limiting portion 253. The yoke 210 is located in the stator shell 250. The inner circumference of the yoke 210 is provided with a mounting groove 211. The mounting groove 211 penetrates the yoke 210 along the axial direction of the motor 1. The permanent magnet 220 is installed in the mounting groove 211. One end of the yoke 210 facing away from the opening 254 stops at the limiting portion 253.

[0069] For example, the yoke 210 can be made of a soft magnetic material that does not generate a magnetic field (i.e., magnetic lines of force) and only transmits magnetic lines of force in the magnetic circuit. For example, the yoke 210 can be made of soft iron, A3 steel, or a soft magnetic alloy with relatively high magnetic permeability. The permanent magnet 220 refers to a magnet that can maintain its magnetism for a long time. The permanent magnet 220 can be made of artificial magnetic steel (iron-nickel-cobalt magnetic steel, etc.) or magnets.

[0070] In addition, the stator housing 250 is used to protect the stator assembly 200 and the rotor assembly 100. The yoke 210, the permanent magnet 220 and the rotor assembly 100 are placed in the stator housing 250 through the opening 254, or are taken out from the stator housing 250. The inner surface of the yoke 210 is provided with a mounting groove 211, and the permanent magnet 220 is arranged in the mounting groove 211. By providing the mounting groove 211 on the inner surface of the yoke 210 and installing the permanent magnet 220 in the mounting groove 211, the positioning between the permanent magnet 220 and the yoke 210 can be achieved, and the distance between the permanent magnet 220 and the rotor assembly 100 is relatively close, and the rotor assembly 100 is more significantly affected by the magnetic field of the permanent magnet 220, thereby ensuring the magnetic field utilization rate of the permanent magnet 220. In addition, the magnetic lines of force generated by the permanent magnet 220 can be transmitted through the yoke 210, avoiding magnetic leakage and improving the magnetic field utilization rate of the permanent magnet 220.

[0071] By setting the limiting portion 253, the relative position between the yoke 210 and the stator housing 250 can be limited in the axial direction of the motor 1. Since the relative position between the permanent magnet 220 and the yoke 210 is fixed, the relative position between the permanent magnet 220 and the stator housing 250 is determined, thereby avoiding installation misalignment and improving assembly accuracy.

[0072] like Figure 5As shown, the above-mentioned limiting portion 253 is formed by the stator case 250 protruding inwardly. That is, when pressure is applied to the outer surface of the stator case 250, the outer surface of the stator case 250 is concave, and the inner surface of the stator case 250 protrudes inwardly to form the limiting portion 253. The limiting portion 253 and the stator case 250 are an integrated structure, and the connection strength between the limiting portion 253 and the stator case 250 is higher. In addition, the processing method of the limiting portion 253 is simple, which improves production efficiency.

[0073] In the circumferential direction of the motor 1, the limiting part 253 and the permanent magnet 220 are arranged at intervals. In this way, on the one hand, the limiting part 253 is prevented from contacting with the permanent magnet 220 when assembling the stator core 240, reducing the probability of the permanent magnet 220 being damaged by the collision of the limiting part 253, ensuring that the magnetic field of the permanent magnet 220 will not be affected, and on the other hand, the stator shell 250 is a magnetic conductive material, for example, the stator shell 250 is metal, reducing the influence of the stator shell 250 on the magnetic field of the permanent magnet 220, ensuring the best magnetic circuit of the permanent magnet 220, which is conducive to ensuring sufficient output power of the motor 1.

[0074] like Figure 5 As shown, in the radial direction of the motor 1, the size of the limit portion 253 is H1, and the wall thickness of the abutment portion between the yoke 210 and the limit portion 253 is H2, wherein the ratio of H1 to H2 is greater than 1 / 2. In other words, in the radial direction of the motor 1, the size of the limit portion 253 is greater than half the wall thickness of the yoke 210. In this way, the abutment area between the limit portion 253 and the yoke 210 is large, which is conducive to ensuring the limiting effect of the limit portion 253 on the yoke 210, so that the relative position between the yoke 210 and the stator housing 250 is more stable.

[0075] like Figure 4 , Fig. 9 and Fig.10 As shown, the motor 1 further includes an end cover 400 , which includes an insertion portion 410 and a cover portion 420 . The insertion portion 410 is inserted into the stator case 250 , and the cover portion 420 is stopped at the end of the first end 251 of the stator case 250 and covers the opening 254 .

[0076] By providing the covering portion 420, the relative position between the end cover 400 and the stator housing 250 in the axial direction of the motor 1 can be limited to prevent the end cover 400 from excessively penetrating into the stator housing 250, and the covering portion 420 can cover the opening 254 to prevent the components in the stator housing 250 from being directly exposed to the air, thereby reducing the probability of damage to the motor 1.

[0077] By providing the insertion portion 410, the contact area between the end cover 400 and the stator shell 250 can be increased. The outer circumferential surface of the insertion portion 410 contacts the inner circumferential surface of the stator shell 250 to improve the connection strength between the end cover 400 and the stator shell 250. The relative position between the end cover 400 and the stator shell 250 is more stable, and pre-positioning between the end cover 400 and the stator shell 250 can be achieved, which is convenient for automated assembly.

[0078] like Figure 6 As shown, the interval L2 between the insertion portion 410 and the yoke 210 is not less than 1 mm. In this way, during the assembly process of the motor 1, there is sufficient space between the insertion portion 410 and the yoke 210 to avoid the situation where the assembly cannot be completed or the assembly is unstable due to processing errors. This can not only absorb the impact of the assembly tolerance and the tolerance, but also ensure the stability of the mass production process of the motor 1 and improve the product yield.

[0079] like Figure 4 As shown, the distance L3 between the end of the permanent magnet 220 facing away from the opening 254 and the second end 252 of the stator housing 250 is not less than 3 mm and not more than 4.5 mm. For example, the distance between the end of the permanent magnet 220 facing away from the opening 254 and the second end 252 of the stator housing 250 may be 3 mm, 3.1 mm, 3.2 mm, 3.3 mm, 3.4 mm, 3.5 mm, 3.6 mm, 3.7 mm, 3.8 mm, 3.9 mm, 4 mm, 4.1 mm, 4.2 mm, 4.3 mm, 4.4 mm or 4.5 mm.

[0080] When the distance L3 between the end of the permanent magnet 220 facing away from the opening 254 and the second end 252 of the stator housing 250 is less than 3 mm, the distance between the end of the permanent magnet 220 facing away from the opening 254 and the second end 252 of the stator housing 250 is reduced. After the length of the permanent magnet 220 increases, due to the processing tolerance and the assembly tolerance, the coil 110 may easily interfere with the second end 252 of the stator housing 250 after protruding from the rotor core 120, thereby affecting the assembly efficiency of the motor 1.

[0081] When the distance L3 between one end of the permanent magnet 220 facing away from the opening 254 and the second end 252 of the stator case 250 is greater than 4.5 mm, the distance between one end of the permanent magnet 220 facing away from the opening 254 and the second end 252 of the stator case 250 is reduced, resulting in an increase in the axial length of the motor 1, which is not conducive to applying the motor 1 to a small space, such as an electric toothbrush.

[0082] The distance L3 between one end of the permanent magnet 220 facing away from the opening 254 and the second end 252 of the stator shell 250 is greater than or equal to 3 mm and less than or equal to 4.5 mm. There is sufficient space between one end of the permanent magnet 220 facing away from the opening 254 and the second end 252 of the stator shell 250 to accommodate the portion of the coil 110 protruding from the rotor core 120, thereby avoiding interference between the coil 110 and the stator shell 250, improving the assembly efficiency of the motor 1, and reducing the axial dimension of the motor 1, which is beneficial to the miniaturization of the motor 1. The motor 1 is more easily applied to the narrow space of an electric toothbrush, and the motor 1 has a wider range of applications.

[0083] like Figure 7-Figure 8 , Figure 11-Figure 12 As shown, the stator core 240 includes two mounting side walls 230 arranged opposite to each other in the first radial direction (the direction indicated by arrow A in the figure), and each mounting side wall 230 is provided with two permanent magnets 220. The rotor core 120 includes a connecting portion 121, two coil mounting portions 122 and two positioning portions 123. The connecting portion 121 is used for transmission connection with the rotating shaft 300 of the motor 1. The two coil mounting portions 122 are arranged on opposite sides of the connecting portion 121 in the first radial direction, and the positioning portion 123 is connected to the side of each coil mounting portion 122 facing away from the connecting portion 121. Among them, the coil 110 is arranged on the coil mounting portion 122.

[0084] That is, each coil 110 interacts with the two permanent magnets 220 of the mounting sidewall 230 adjacent thereto to ensure that the magnetic field of the permanent magnet 220 on each mounting sidewall 230 can always cover the coil 110 adjacent thereto when the rotor assembly 100 rotates.

[0085] The connecting portion 121 and the positioning portion 123 can limit the coil 110 to ensure the stability of the coil 110 on the coil mounting portion 122, and the distance between the coil 110 and the permanent magnet 220 is closer, which is beneficial to improving the magnetic field utilization rate of the permanent magnet 220 and the output power of the motor 1 is higher.

[0086] like Figure 7-Figure 8 , Figure 11-Figure 12 As shown, the side of the positioning portion 123 facing away from the coil mounting portion 122 is configured as an outwardly convex arc surface. In the circumferential direction of the motor 1, the size of the inner circumference of the permanent magnet 220 is W1, the size of the arc surface is W2, and the ratio of W1 to W2 is greater than 1 / 2.

[0087] Since each mounting side wall 230 is provided with two permanent magnets 220 , the sum of the dimensions of the inner circumferential surfaces of the permanent magnets 220 of each mounting side wall 230 is greater than the dimension of the arc surface in the circumferential direction of the motor 1 , that is, 2×W1>W2.

[0088] In this way, the magnetic field coverage of each permanent magnet 220 installed on the side wall 230 is larger, and when the rotor core 120 rotates to any position, the permanent magnet 220 corresponds to the coil 110, thereby improving the output power of the motor 1.

[0089] like Fig.11 As shown, the positioning portion 123 exceeds the coil 110 in the second radial direction (the direction indicated by the arrow B in the figure), and the first radial direction and the second radial direction are perpendicular to each other. When the end of the rotor core 120 is stopped by the stator core 240, the positioning portion 123 contacts the positioning core before the coil 110, and the coil 110 does not contact the stator core 240, thereby avoiding the occurrence of the wire of the coil 110 being worn or broken, reducing the probability of damage to the coil 110, and extending the service life of the coil 110.

[0090] like Figure 4 As shown, the length L4 of the permanent magnet 220 is not less than 30 mm and not more than 40 mm. For example, the length of the permanent magnet 220 can be 30 mm, 31 mm, 32 mm, 33 mm, 34 mm, 35 mm, 35.3 mm, 36 mm, 37 mm, 38 mm, 39 mm or 40 mm.

[0091] When the length L4 of the permanent magnet 220 is less than 30 mm, the length of the permanent magnet 220 cannot effectively absorb the manufacturing tolerance and process assembly tolerance of each component in the motor 1, resulting in that the permanent magnet 220 may not cover the rotor core 120 in the circumferential direction of the motor 1. At this time, the tolerance has a greater impact on the power output of the motor 1.

[0092] When the length of the permanent magnet 220 is greater than 40 mm, the cost of the permanent magnet 220 is high, and the permanent magnet 220 occupies a large space in the motor 1 , which is inconvenient for assembling the motor 1 and may cause the axial dimension of the motor 1 to increase.

[0093] The length L4 of the permanent magnet 220 is greater than or equal to 30 mm and less than or equal to 40 mm. In this way, within a limited length, the cost of the permanent magnet 220 is low, and the effect of absorbing the manufacturing tolerances and process assembly tolerances of each component is more obvious and reliable, reducing the impact of the tolerance on the power output of the motor 1.

[0094] The same or similar numbers in the drawings of this embodiment correspond to the same or similar parts; in the description of this application, it should be understood that if the terms "up", "down", "left", "right", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the drawings, it is only for the convenience of describing this application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and cannot be understood as limitations on this application. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0095] The above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A motor, characterized in that: include: A rotor assembly, the rotor assembly comprising a rotor core and a coil, wherein the coil is arranged on an outer peripheral surface of the rotor core; A stator assembly, wherein the stator assembly is sleeved on the rotor assembly, the rotor assembly is rotatable relative to the stator assembly, and the stator assembly comprises a stator core and a permanent magnet; Wherein, in the axial direction of the motor, the length of the permanent magnet is greater than the length of the rotor core, and the two ends of the rotor core do not exceed the two ends of the permanent magnet.

2. The motor according to claim 1, characterized in that In the axial direction of the motor, two ends of the permanent magnet extend beyond two ends of the rotor core.

3. The motor according to claim 2, characterized in that In the axial direction of the motor, an end of the permanent magnet is located between an end of the coil and an end of the rotor core.

4. The motor according to claim 2, characterized in that In the axial direction of the motor, the end of the permanent magnet exceeds the end of the rotor core by a dimension L1, 3mm≥L1≥0.5mm.

5. The motor according to claim 1, characterized in that The stator core comprises: stator housing; A yoke, wherein the yoke is located in the stator shell, an inner circumferential surface of the yoke is provided with a mounting groove, the mounting groove penetrates the yoke along the axial direction of the motor, and the permanent magnet is mounted in the mounting groove; Wherein, in the axial direction of the motor, the end of the permanent magnet is flush with the end of the yoke, or the end of the permanent magnet exceeds the end of the yoke.

6. The motor according to claim 1, characterized in that The stator core comprises: A stator shell, the stator shell having a first end and a second end, the first end of the stator shell being provided with an opening, and the inner circumferential surface of the stator shell being provided with a limiting portion; A yoke is located in the stator shell, an inner circumferential surface of the yoke is provided with a mounting groove, the mounting groove penetrates the yoke along the axial direction of the motor, the permanent magnet is installed in the mounting groove, and one end of the yoke facing away from the opening stops at the limiting portion.

7. The motor according to claim 6, characterized in that The limiting portion is formed by the stator shell protruding inwardly.

8. The motor according to claim 6, characterized in that In the circumferential direction of the motor, the limiting portion and the permanent magnet are arranged at intervals.

9. The motor according to claim 6, characterized in that In the radial direction of the motor, the size of the limiting portion is H1; The wall thickness of the abutment portion between the yoke and the limiting portion is H2; Among them, the ratio of H1 to H2 is greater than 1 / 2.

10. The motor according to claim 6, characterized in that Also includes: An end cover, the end cover comprising an inserting portion and a covering portion, the inserting portion being inserted into the stator shell, the covering portion being stopped at an end portion of the first end of the stator shell and covering the opening; Wherein, the interval between the insertion portion and the magnetic yoke is not less than 1 mm.

11. The motor according to claim 6, characterized in that The distance between the end of the permanent magnet facing away from the opening and the second end of the stator shell is not less than 3 mm and not more than 4.5 mm.

12. The motor according to any one of claims 1 to 11, characterized in that: The stator core comprises two mounting side walls which are arranged opposite to each other in a first radial direction, and each mounting side wall is provided with two permanent magnets; The rotor core comprises a connecting portion, two coil mounting portions and two positioning portions, wherein the connecting portion is used for transmission connection with the motor shaft, the two coil mounting portions are arranged on opposite sides of the connecting portion in the first radial direction, and the positioning portion is connected to a side of each coil mounting portion facing away from the connecting portion; Wherein, the coil is arranged on the coil mounting portion.

13. The motor according to claim 12, characterized in that The side of the positioning portion facing away from the coil mounting portion is configured as an outwardly convex arc surface; Wherein, in the circumferential direction of the motor, the size of the inner circumferential surface of the permanent magnet is W1, the size of the arc surface is W2, and the ratio of W1 to W2 is greater than 1 / 2.

14. The motor according to claim 12, characterized in that The positioning portion exceeds the coil in a second radial direction, and the first radial direction and the second radial direction are perpendicular to each other.

15. The motor according to any one of claims 1 to 11, characterized in that: The length of the permanent magnet is not less than 30 mm and not more than 40 mm.

16. An electric toothbrush, characterized in that: include: Handle shell; A movement, the movement comprising a motor according to any one of claims 1-15, the movement being installed in the handle shell.

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