Rotor bracket, rotor assembly, motor, and electric toothbrush

Abstract

To provide a rotor bracket with a low attenuation degree of a rotation amplitude and small required power when a motor is applied to a high-frequency forward / reverse rotation operation state.SOLUTION: A rotor bracket 31 includes: a central shaft 32; and a mounting portion protruding on an outer circumferential surface of the central shaft. A surface of the mounting portion away from the central shaft is provided with a plurality of accommodating grooves 34 arranged around a shaft line at intervals, a surface of the mounting portion away from the central shaft is further provided with a material saving groove 35, and a bottom of the material saving groove extends around the shaft line of the central shaft and penetrates a bottom wall surface of the accommodating groove. By providing the material saving groove on the rotor bracket, a mass of the rotor bracket can be reduced, and in particular, the bottom of the material saving groove extends toward the accommodating groove, which not only further reduces the mass, but also reduces the moment of inertia thereof.SELECTED DRAWING: Figure 8

Description

Technical Field

[0001] This application relates to the technical field of small motors, and particularly to a rotor bracket, a rotor assembly, a motor, and an electric toothbrush.

Background Art

[0002] A motor can be driven by electric power to realize the rotational movement of its rotor. In general applications, the motor rotates forward for a long time, or stops and then rotates in reverse for a long time again. In such applications, the angular acceleration received by the rotor is small.

[0003] An electric toothbrush is a portable electronic device, and the motor used on the portable electronic device has a small volume. In the field of electric toothbrushes, for example, in an ultrasonic electric toothbrush, the motor not only requires miniaturization but also requires high-frequency forward and reverse rotation. The Chinese Utility Model Registration Bulletin with the registration number CN215498605U and the name "Electric Toothbrush Motor and Electric Toothbrush" discloses an electric toothbrush in which the motor operates with high-frequency forward and reverse rotation. However, the forward and reverse reset of the rotor in this registration bulletin requires elastic reset components, thereby greatly limiting the rotation frequency of the rotor.

[0004] With the development of technology, an electric toothbrush that does not require an elastic reset component for the forward and reverse reset of the rotor has emerged. The forward and reverse rotation frequency of the rotor of such an electric toothbrush can reach even 66,000 revolutions per minute. In applications with high-frequency forward and reverse rotation, the angular acceleration received by the rotor bracket is large. In order to adapt to such operating conditions, the motor used in the electric toothbrush has already reduced the ratio of the outer diameter to the axial dimension to reduce the moment of inertia. However, the electric power required to maintain the normal operation of the motor is still large, and when high-frequency forward and reverse rotation occurs, the difference between the actual angular displacement and the preset angular displacement is large, that is, there is a large attenuation of the rotation amplitude.

Prior Art Documents

Patent Documents

[0005] [Patent Document 1] Chinese Patent Publication Gazette No. CN111313581A [Patent Document 2] Chinese Patent Publication Gazette No. CN113809853A [Patent Document 3] Chinese Utility Model Publication Gazette No. CN208209652U [Summary of the Invention] [Problems to be Solved by the Invention]

[0006] The main object of the present application is to provide a rotor bracket, a rotor assembly, a motor, and an electric toothbrush for solving the technical problems that the inertia moment of the conventional motor bracket is large, the attenuation degree of the rotational amplitude when used in the operating condition of high-frequency forward and reverse rotation is high, and the required power is large. [Means for Solving the Problems]

[0007] In order to achieve the above object, the rotor bracket according to the present application includes a central axis, and a mounting portion protruding from the outer peripheral surface of the central axis, and a plurality of accommodation grooves are provided on the surface of the mounting portion away from the central axis at intervals around the axis of the central axis. A material saving groove is further provided on the surface of the mounting portion away from the central axis, and the bottom of the material saving groove extends around the axis of the central axis and penetrates the bottom wall surface of the accommodation groove.

[0008] Preferably, the material saving groove extends around the axis of the central axis for one week and presents an annular shape.

[0009] Preferably, the bottom wall surface of the material saving groove is a rotating surface coaxial with the central axis.

[0010] Preferably, the bottom wall surface of the material saving groove is a cylindrical surface.

[0011] Preferably, the outer diameter of the bottom wall surface of the material reduction groove is R1, the outer diameter of the axial section close to the attachment portion of the central axis is R2, and R1 is greater than or equal to R2.

[0012] Preferably, in the circumferential direction extending around the axis of the central axis, the minimum distance between two adjacent accommodation grooves is D1, the minimum distance from the bottom wall surface of the accommodation groove to the outer peripheral surface of the central axis is D2, and D1 is greater than D2.

[0013] Preferably, the attachment portion includes a plurality of silicon steel plates bonded along the axis of the central axis, and D2 is 5 mm or more.

[0014] Preferably, the attachment portion is installed integrally with the central axis.

[0015] Preferably, the length of the attachment portion is L1, the distance between the tip surface of the attachment portion and the tip surface of the central axis is L2, and the value of L1:L2 is [0.8, 2.5].

[0016] Preferably, a chamfer is provided at the connection portion between the tip surface of the attachment portion and the outer peripheral surface of the central axis.

[0017] Preferably, a plurality of the material reduction grooves are arranged at intervals along the axis of the central axis.

[0018] Preferably, the plurality of material reduction grooves are arranged at equal intervals along the axis of the central axis.

[0019] Preferably, each of the material reduction grooves has an equal axial width.

[0020] Preferably, the axial width of the material reduction groove is W1, the interval between two adjacent material reduction grooves in the direction extending along the axis of the central axis is W2, and W1 is smaller than W2.

[0021] Preferably, the axial width of each of the material reduction grooves is arranged to decrease from the front to the back.

[0022] Preferably, a plurality of the material reduction grooves are arranged such that the number is dense in the front and sparse in the back along the axis of the central axis.

[0023] This application further provides a rotor assembly including a rotor bracket and a magnetic body. The rotor bracket is the rotor bracket described above. The magnetic body is fixedly installed in the accommodation groove. The magnetic body covers a part of the material reduction groove, and the magnetic body and the bottom wall surface of the material reduction groove are installed at an interval.

[0024] Preferably, the accommodation groove extends along the axis of the central axis and has an elongated shape, and penetrates the front end surface and / or the rear end surface of the attachment portion. The magnetic body is assembled into the accommodation groove along the axial direction.

[0025] Preferably, a plurality of the magnetic bodies joined together along the axial direction are installed in each of the accommodation grooves.

[0026] Preferably, in the direction extending along the axis of the central axis, the joints of two adjacent magnetic bodies are installed offset from the material reduction groove.

[0027] Preferably, the axial length of the magnetic body is larger than the axial length of the accommodation groove, and the magnetic body protrudes more than the front end surface and / or the rear end surface of the attachment portion along the axial direction.

[0028] Preferably, the rotor assembly further includes a filler provided in the material reduction groove, and the density of the filler is smaller than the density of the attachment portion.

[0029] Preferably, the outer surface of the magnetic body protrudes more than the outer peripheral surface of the attachment portion, and the outer surface of the filler is flush with the outer peripheral surface of the attachment portion.

[0030] Preferably, the filler is an adhesive that fixedly connects the magnetic body and the attachment portion.

[0031] This application further provides a motor including a motor case, a stator assembly, and a rotor assembly, wherein the rotor assembly is the rotor assembly described above.

[0032] Preferably, the motor further includes a detection assembly, the detection assembly includes a circuit board and a plurality of Hall sensors electrically connected to the circuit board, and the Hall sensors are coupled to magnetic marks on the rotor assembly.

[0033] Preferably, the detection assembly is provided at the rear end of the motor case, the motor case is provided with a lead wire hole between the detection assembly and the stator assembly, and the lead wire hole is used to draw out the lead wires of the detection assembly and the stator assembly from the motor case.

[0034] This application further provides an electric toothbrush, which includes a handle, a motor, and a brush head. The motor is provided in the inner cavity of the handle. The central axis of the rotor assembly extends from the tip of the handle, and the brush head is attached to the tip of the central axis. The motor is the motor described above.

Advantages of the Invention

[0035] By installing a material-saving groove on the rotor bracket of this application, the mass of the rotor bracket can be reduced. In particular, the bottom of the material-saving groove extends toward the accommodation groove, which not only further reduces the mass, First, compared with extending along the axial direction of the central axis, the support strength of the accommodation groove is not further weakened, Second, when a ferromagnetic material is used for the attachment portion, the magnetic permeability of the attachment portion is not weakened, Thirdly, by communicating the material reduction groove and the accommodation groove with each other, the processing of the rotor bracket is made easier.

[0036] Since the mass of the rotor bracket of the present application is reduced, its moment of inertia is also reduced. As a result, when applied to the operating conditions of high-frequency forward and reverse rotation, the degree of attenuation of the rotational amplitude is low and the required power is small.

Brief Description of the Drawings

[0037] To more clearly explain the technical solution in the embodiment of the present application, the drawings required for the description of the embodiment are briefly described below. Obviously, the drawings in the following description are only some embodiments of the present application, and those skilled in the art can obtain other drawings based on these drawings on the premise of not paying creative labor.

Figure 1

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Figure 8

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Figure 12

Embodiments for Carrying out the Invention

[0038] Hereinafter, with reference to the drawings in the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described. Obviously, the described embodiments are only some embodiments of the present application, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present application without creative efforts shall fall within the protection scope of the present application.

[0039] Referring to FIGS. 5 to 10, in one embodiment, the rotor bracket 31 according to the present application includes a central axis 32, and a mounting portion 33 protruding from the outer peripheral surface of the central axis 32. A plurality of accommodation grooves 34 are provided on the surface of the mounting portion 33 away from the central axis 32 at intervals around the axis of the central axis 32. A material reduction groove 35 is further provided on the surface of the mounting portion 33 away from the central axis 32. The bottom of the material reduction groove 35 extends around the axis of the central axis 32 and penetrates the bottom wall surface of the accommodation groove 34.

[0040] In this embodiment, the changing magnetic field drives the rotor assembly 30 to rotate. The central axis 32 is used to transmit the rotational motion. For example, when applying an electric toothbrush, the tip of the central axis 32 is used to attach the brush head.

[0041] The mounting portion 33 attaches the magnetic body 36a of the rotor assembly 30 by means of the accommodation groove 34. The mounting portion 33 is preferably made of a ferromagnetic material, such as a material with high magnetic permeability, low iron loss, and low magnetic hysteresis. In this way, the utilization efficiency of magnetic energy can be improved, and a larger proportion of magnetic energy can be converted into kinetic energy.

[0042] Since the installation of the accommodation groove 34 does not completely occupy the outer peripheral surface of the attachment portion 33, a material reduction groove 35 can be formed in another area of the outer peripheral surface of the attachment portion 33. By installing the material reduction groove 35, the mass of the rotor bracket 31 can be reduced. In particular, the bottom of the material reduction groove 35 extends toward the accommodation groove 34, which not only further reduces the mass, but also First, compared with extending along the axial direction of the central axis 32, the support strength of the accommodation groove 34 is not further weakened. Second, when a ferromagnetic material is used for the attachment portion 33, the magnetic permeability of the attachment portion 33 is not weakened. Third, by communicating the material reduction groove 35 and the accommodation groove 34 with each other, the processing of the rotor bracket 31 is made easier.

[0043] Since the mass of the rotor bracket 31 of the present application is reduced, its moment of inertia is also reduced. As a result, when applied to the operating conditions of high-frequency forward and reverse rotation, the degree of attenuation of the rotational amplitude is low and the required power is small.

[0044] Furthermore, the material reduction groove 35 extends around the axis of the central axis 32 for one week and presents an annular shape. In this embodiment, the mass of the rotor bracket 31 is further reduced, and the fact that the material reduction groove 35 presents an annular shape is also advantageous for achieving better dynamic balance during processing and movement. Preferably, the bottom wall surface of the material reduction groove 35 is a rotating surface coaxial with the central axis 32. Furthermore, the bottom wall surface of the material reduction groove 35 is a cylindrical surface.

[0045] Furthermore, referring to FIG. 3, the outer diameter of the bottom wall surface of the material reduction groove 35 is R1, the outer diameter of the axial section close to the attachment portion 33 of the central axis 32 is R2, and R1 is greater than or equal to R2. In this embodiment, by restricting the size of R2, it is possible to avoid the weakening of the bending resistance of the entire rotor bracket 31 caused by the installation of the material reduction groove 35. When the attachment portion 33 is formed by overlapping a plurality of silicon steel sheets, such an installation facilitates the formation of a closed fitting hole, is connected to each wing portion of the attachment portion 33, reduces the number of parts, and further facilitates the installation.

[0046] Furthermore, referring to FIGS. 7 and 10 together, in the circumferential direction extending around the axis of the central axis 32, the minimum distance between two adjacent accommodation grooves 34 is D1, and the minimum distance from the bottom wall surface of the accommodation groove 34 to the outer peripheral surface of the central axis 32 is D2. D1 is greater than D2. Thus, it is advantageous to ensure the support strength of the accommodation groove 34. When assembling the magnetic body 36a, the portion between two adjacent accommodation grooves 34 in the circumferential direction is not easily deformed, making the assembly easier. Preferably, the attachment portion 33 includes a plurality of silicon steel sheets that are bonded along the axis of the central axis 32, and D2 is 5 mm or more. The silicon steel sheets are formed by blanking of the sheet material. Fitting a plurality of silicon steel sheets onto the central axis 32 can reduce the processing cost. Moreover, the silicon steel sheets have material properties of high magnetic permeability, low iron loss, and low magnetic hysteresis, which is advantageous for improving the utilization efficiency of magnetic energy.

[0047] Furthermore, the attachment portion 33 is installed integrally with the central axis 32. This is advantageous for ensuring the structural strength of the entire rotor bracket 31. Specifically, the integral rotor bracket 31 may employ a CNC machine tool, also known as a main spindle table moving type CNC automatic lathe, an economy type turning and milling compound machine tool, or a sliding headstock machine tool. Belonging to precision machining equipment, it can simultaneously complete composite machining such as turning, milling, drilling, boring, and engraving in one go, and is mainly used for mass machining of precision metal parts and shaft-shaped irregular parts, and may also be used for slow wire cutting.

[0048] Furthermore, the length of the attachment portion 33 is L1, and the distance between the tip surface of the attachment portion 33 and the tip surface of the central axis 32 is L2. The value of L1:L2 is [0.8, 2.5]. By installing in this way, the bending resistance ability of the rotor bracket 31 can be ensured, and the reliability of the long-term use of the rotor bracket 31 can be ensured.

[0049] Furthermore, in order to disperse stress, a chamfer is provided at the connection location between the tip surface of the attachment portion 33 and the outer peripheral surface of the central axis 32.

[0050] Furthermore, a plurality of material reduction grooves 35 are arranged at intervals along the axis of the central axis 32. In this way, a larger number of magnetic bodies 36a can be arranged, thereby controlling the rotation of the rotor assembly 30 more efficiently and precisely.

[0051] Furthermore, the plurality of material reduction grooves 35 are arranged at equal intervals along the axis of the central axis 32. In this way, the processing of the rotor bracket 31 is made easier. Preferably, the axial width of each material reduction groove 35 is equal.

[0052] Furthermore, in order to better balance mass reduction and structural strength, the axial width of the material reduction groove 35 is W1, and in the direction extending along the axis of the central axis 32, the interval between two adjacent material reduction grooves 35 is W2, and W1 is smaller than W2.

[0053] Furthermore, in order to improve the comfort of using the portable electronic device, the axial width of each material reduction groove 35 is arranged to decrease gradually from front to back. In this way, the center of gravity of the rotor bracket 31 is farther from the tip of the central axis 32, thereby reducing the gripping torque of the portable electronic device. For example, it is more labor-saving to grip a portable electronic device such as an electric toothbrush.

[0054] Furthermore, the plurality of material reduction grooves 35 are arranged along the axis of the central axis 32, with a higher density at the front and a lower density at the back in terms of quantity. Such an arrangement can similarly move the center of gravity of the rotor bracket 31 farther from the tip of the central axis 32, thereby making it more labor-saving to grip the portable electronic device.

[0055] Referring to FIGS. 5 to 10, in one embodiment, the present application further provides a rotor assembly 30 including a rotor bracket 31 and a magnetic body 36a. The rotor bracket 31 is the rotor bracket 31 described above. The magnetic body 36a is fixedly installed in the accommodation groove 34. The magnetic body 36a covers a part of the material reduction groove 35, and the magnetic body 36a and the bottom wall surface of the material reduction groove 35 are installed at an interval. For the specific structure of the rotor bracket 31, please refer to the above embodiment. Since the rotor assembly 30 adopts all the technical solutions of all the above embodiments, it similarly has all the beneficial effects brought by the technical solutions of the above embodiments, and the description is omitted here. In this embodiment, the magnetic body 36a generally adopts a permanent magnet 36a, and the magnetic bodies 36a in different orientations have different magnetic poles.

[0056] Furthermore, the accommodation groove 34 extends along the axis of the central axis 32 and presents an elongated shape, and penetrates the front end surface and / or the rear end surface of the mounting portion 33. The magnetic body 36a is assembled into the accommodation groove 34 along the axial direction. In this embodiment, the accommodation groove 34 presents an elongated shape, so that an increase in the moment of inertia caused by an increase in the radial dimension can be avoided. And since the accommodation groove 34 is open on at least one side in the axial direction and the magnetic body 36a can be assembled into the accommodation groove 34 along the axial opening, this embodiment is further advantageous for improving the assembly efficiency.

[0057] Referring to FIGS. 11 and 12, in another embodiment, a plurality of magnetic bodies 36b joined axially are installed in each accommodation groove 34. In this way, the axial dimension of a single magnetic body 36b is small, so that accidental breakage is less likely to occur. And in the implementation where the accommodation groove 34 is open on both sides in the axial direction, the plurality of magnetic bodies 36b can be assembled into the accommodation groove 34 along the forward and reverse directions in the axial direction. In this way, it is advantageous for improving the assembly efficiency.

[0058] Furthermore, in the direction extending along the axis of the central axis 32, the joints of two adjacent magnetic bodies 36b are arranged offset from the material-saving groove 35. In this embodiment, the plurality of magnetic bodies 36b joined together can be better supported, and the warping at the ends can be avoided.

[0059] Referring to FIGS. 5 to 12, in the above two embodiments, the axial lengths of the magnetic bodies 36a and 36b are greater than the axial length of the accommodation groove 34, and the magnetic bodies 36a and 36b protrude more than the front end face and / or the rear end face of the mounting portion 33 along the axial direction. In this way, the magnetic force can be cut more sufficiently, and furthermore, the utilization efficiency of magnetic energy can be improved.

[0060] Furthermore, the rotor assembly 30 further includes a filler provided in the material-saving groove 35, and the density of the filler is smaller than the density of the mounting portion 33. In this embodiment, the filler can reduce air resistance and noise during rotation by reducing the hollow region of the rotor assembly 30.

[0061] Furthermore, the outer surfaces of the magnetic bodies 36a and 36b protrude more than the outer peripheral surface of the mounting portion 33, and the outer surface of the filler is flush with the outer peripheral surface of the mounting portion 33. In this way, while avoiding interference between the mounting portion 33, the filler and the stator assembly 20, the air resistance and noise during operation can be further reduced.

[0062] Furthermore, during operation, the magnetic bodies 36a and 36b are subject to large inertial forces, for example, radially outward and circumferentially around the axis of the central axis 32. Therefore, by using the filler as an adhesive that fixedly connects the magnetic bodies 36a and 36b to the mounting portion 33, the ability to prevent the magnetic bodies 36a and 36b from coming off can be improved together.

[0063] Referring to FIGS. 5 to 10, in order to prevent the magnetic body 36a from loosening along the radial direction of the central axis 32, in one embodiment, the present application further provides a rotor assembly 30 used in a motor 100 of a portable electronic device. The rotor assembly 30 includes a rotor bracket 31 and a magnetic body 36a. The rotor bracket 31 includes a central axis 32 and a mounting portion 33 protruding from the outer peripheral surface of the central axis 32. A plurality of receiving grooves 34 are provided on the surface of the mounting portion 33 away from the central axis 32 and are arranged at intervals around the axis of the central axis 32. The magnetic body 36a is fixedly installed in the receiving groove 34. The receiving groove 34 extends along the axis of the central axis 32 and has an elongated shape, and penetrates the front end surface and / or the rear end surface of the mounting portion 33. The width of the cross-sectional shape of the receiving groove 34 is gradually reduced outward along the radial direction. The magnetic body 36a is assembled into the receiving groove 34 along the axial direction. For the specific structure of the rotor bracket 31, please refer to the above embodiment. Since the rotor assembly 30 adopts all the technical solutions of all the above embodiments, it similarly has all the beneficial effects brought about by the technical solutions of the above embodiments, and the description is omitted here.

[0064] In this embodiment, the changing magnetic field drives the rotor assembly 30 to rotate. The central axis 32 is used to transmit the rotational motion. For example, when applying an electric toothbrush, the tip of the central axis 32 is used to attach the brush head.

[0065] The mounting portion 33 attaches the magnetic body 36a of the rotor assembly 30 by means of the receiving groove 34. The mounting portion 33 is preferably made of a ferromagnetic material, such as a material with high magnetic permeability, low iron loss, and low magnetic hysteresis. In this way, the utilization efficiency of magnetic energy can be improved, and a larger proportion of magnetic energy can be converted into kinetic energy.

[0066] Since the width of the cross-sectional shape of the receiving groove 34 is gradually reduced outward along the radial direction, the magnetic body 36a can be restricted from sliding outward along the radial direction.

[0067] Furthermore, in order to easily machine the accommodation groove 34 on the rotor bracket 31 with a small ratio of outer diameter to axial dimension, both of the opposing side wall surfaces of the accommodation groove 34 are installed obliquely with respect to the bottom wall surface of the accommodation groove 34. In order to better achieve dynamic balance, preferably, two opposing sides of the cross-sectional shape of the accommodation groove 34 are symmetrically installed.

[0068] Furthermore, in order to strengthen the fixation of the magnetic body 36a, an adhesive accumulation groove is formed in the bottom wall surface of the accommodation groove 34. The magnetic body 36a covers the adhesive accumulation groove, and the rotor assembly 30 further includes an adhesive filled between the magnetic body 36a and the bottom wall surface of the adhesive accumulation groove. The adhesive fixedly connects the magnetic body 36a and the attachment portion 33.

[0069] Furthermore, in order to reduce the moment of inertia of the rotor bracket 31, a hollow groove is further provided on the surface away from the central axis 32 of the attachment portion 33. In order to facilitate machining and further reduce the moment of inertia of the rotor bracket 31, the hollow groove communicates with the adhesive accumulation groove, and the adhesive is further filled in the hollow groove. The density of the filling is smaller than the density of the attachment portion 33.

[0070] Furthermore, in order to avoid interference between the rotor assembly 30 and the stator assembly 20 and reduce air resistance and noise, the outer surface of the magnetic body 36a protrudes more than the outer peripheral surface of the attachment portion 33, and the outer surface of the filling is flush with the outer peripheral surface of the attachment portion 33.

[0071] Referring to FIGS. 11 and 12, in another embodiment, in the circumferential direction extending around the axis of the central axis 32, the adhesive accumulation grooves and the hollow grooves are in contact with each other in pairs to form an annular shape. In this way, the processing of the adhesive accumulation grooves and the hollow grooves is made easier. In each accommodation groove 34, a plurality of magnetic bodies 36b joined along the axial direction are installed. In the direction extending along the axis of the central axis 32, the joints of two adjacent magnetic bodies 36b are arranged offset from the adhesive accumulation grooves. In this way, it is possible to avoid the length of the magnetic body 36b becoming too large and being easily broken. And in the implementation where the accommodation groove 34 opens on both sides in the axial direction, the plurality of magnetic bodies 36b can be assembled into the accommodation groove 34 along the forward and reverse directions in the axial direction. By arranging the joints of the magnetic bodies 36b offset from the adhesive accumulation grooves, the joined magnetic bodies 36b can be better supported and the warping at the ends can be avoided.

[0072] Referring to FIGS. 7 and 10, in the circumferential direction extending around the axis of the central axis 32, the adhesive accumulation grooves and the hollow grooves are in contact with each other in pairs to form an annular shape. In the circumferential direction extending around the axis of the central axis 32, the minimum distance between two adjacent accommodation grooves 34 is D1, and the minimum distance from the bottom wall surface of the accommodation groove 34 to the outer peripheral surface of the central axis 32 is D2. D1 is larger than D2. In this way, it is advantageous to ensure the support strength of the accommodation groove 34. When assembling the magnetic body 36a, the part between two adjacent accommodation grooves 34 in the circumferential direction is not easily deformed, and the assembly is easier to perform.

[0073] Referring to FIGS. 1 to 4, the present application further provides a motor 100 including a motor case 10, a stator assembly 20, and a rotor assembly 30. The rotor assembly 30 is the rotor assembly 30 as described above. For the specific structure of the rotor assembly 30, please refer to the above embodiments. Since the motor 100 adopts all the technical solutions of all the above embodiments, it similarly has all the beneficial effects brought about by the technical solutions of the above embodiments, and the description thereof is omitted here. In this embodiment, the motor case 10 is used to provide support and protection for the internal members. The stator assembly 20 generally includes a bobbin and a coil winding wound around the bobbin.

[0074] Furthermore, the motor 100 further includes a detection assembly 40. The detection assembly 40 includes a circuit board 41 and a plurality of Hall sensors 42 electrically connected to the circuit board 41. The Hall sensors 42 are coupled with magnetic marks 50 on the rotor assembly 30.

[0075] In this embodiment, the circuit board 41 is used to process the signals received by the Hall sensors 42 and then transmit them to the lower control unit. The magnetic marks 50 may be magnetic bodies 36a and 36b on the rotor assembly 30, or may be magnetic attraction components located outside the bearing shown in FIGS. 3 and 4. Such an installation may be away from the stator assembly 20 and can generate a directional magnetic field, thereby making magnetic detection more accurate.

[0076] Furthermore, the detection assembly 40 is provided at the rear end of the motor case 10. The motor case 10 is provided with a lead wire hole 11 between the detection assembly 40 and the stator assembly 20. The lead wire hole 11 is used to draw out the lead wires of the detection assembly 40 and the stator assembly 20 from the motor case 10. In this way, the lead wire distance can be shortened and the fixing of the motor 100 can be facilitated, that is, the motor 100 can be more easily fixed by using the rear end face of the motor 100. It is provided at the rear end of the motor case 10.

[0077] This application further provides a motor 100 for a portable electronic device, which includes a motor case 10, a stator assembly 20, and a rotor assembly 30. The rotor assembly 30 is the rotor assembly 30 as described above. For the specific structure of the rotor assembly 30, please refer to the above embodiments. Since this motor 100 adopts all the technical solutions of all the above embodiments, it similarly has all the beneficial effects brought about by the technical solutions of the above embodiments, and the description thereof is omitted here. In this embodiment, the portable electronic device may be an electric toothbrush, a hair dryer, a small vacuum cleaner, etc. The motor case 10 is used to provide support and protection for the internal members. The stator assembly 20 generally includes a bobbin and a coil winding wound around the bobbin.

[0078] This application further provides an electric toothbrush (not shown) including a handle, a motor 100, and a brush head. The motor 100 is provided in the inner cavity of the handle. The central axis 32 of the rotor assembly 30 extends from the tip of the handle. The brush head is attached to the tip of the central axis 32. The motor 100 is the motor 100 as described above. For the specific structure of the motor 100, please refer to the above embodiments. Since this electric toothbrush adopts all the technical solutions of all the above embodiments, it similarly has all the beneficial effects brought about by the technical solutions of the above embodiments, and the description thereof is omitted here. In this embodiment, the handle is generally provided in a long shape that is easy to grip, and the brush head may be removably fixed to the central axis 32.

[0079] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit them. Although this application has been described in detail with reference to the above embodiments, as can be understood by those skilled in the art, it is still possible to modify the technical solutions described in the above embodiments or perform equivalent substitutions for some of their technical features. These modifications or substitutions do not deviate from the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A central axis, a mounting portion provided on an outer peripheral surface of the central shaft, the mounting portion having a surface away from the central shaft and a plurality of accommodating grooves arranged at intervals around an axis of the central shaft, a material-saving groove is further provided on a surface of the mounting portion away from the central axis, and a bottom of the material-saving groove extends around the axis of the central axis and penetrates a bottom wall surface of the accommodating groove.

2. 2. The rotor bracket according to claim 1, wherein the material-saving groove is annular and extends around the axis of the central shaft.

3. 3. The rotor bracket of claim 2, wherein a bottom wall surface of said material-saving groove is a surface of revolution coaxial with said central axis.

4. 4. The rotor bracket according to claim 3, wherein the bottom wall surface of the material-saving groove is a cylindrical surface.

5. 5. The rotor bracket of claim 4, wherein an outer diameter of a bottom wall surface of the material-saving groove is R1, an outer diameter of a section of the central shaft near the mounting portion is R2, and R1 is greater than or equal to R2.

6. 6. The rotor bracket of claim 5, wherein in a circumferential direction extending around the axis of the central shaft, a minimum distance between two adjacent accommodating grooves is D1, a minimum distance from a bottom wall surface of the accommodating groove to an outer circumferential surface of the central shaft is D2, and D1 is greater than D2.

7. 7. The rotor bracket according to claim 6, wherein the mounting portion includes a plurality of silicon steel plates bonded together along an axis of the central shaft, and D2 is 5 mm or more.

8. 3. The rotor bracket of claim 2, wherein said material-saving grooves are spaced apart from one another along the axis of said central shaft.

9. 2. The rotor bracket of claim 1, wherein said material-saving grooves are spaced apart along an axis of said central shaft.

10. 10. The rotor bracket of claim 9, wherein a plurality of said material-saving grooves are equally spaced along an axis of said central shaft.

11. The rotor bracket of claim 10 , wherein each of said material-saving grooves has an equal axial width.

12. 12. The rotor bracket of claim 11, wherein an axial width of the material-saving groove is W1, and a distance between two adjacent material-saving grooves in a direction extending along an axis of the central shaft is W2, and W1 is smaller than W2.

13. 11. The rotor bracket of claim 10, wherein the axial width of each of the material-saving grooves is tapered from front to rear.

14. The rotor bracket of claim 11, wherein the material-saving grooves are disposed along an axis of the central shaft in a dense manner in the front and a sparse manner in the rear.

15. The rotor bracket of claim 1 , wherein the mounting portion is integrally disposed with the central shaft.

16. 16. The rotor bracket of claim 15, wherein the length of the mounting portion is L1, the distance between a tip surface of the mounting portion and a tip surface of the central shaft is L2, and the value of L1:L2 is [0.8, 2.5].

17. 17. The rotor bracket according to claim 16, wherein a chamfer is provided at a connection point between a tip surface of the mounting portion and an outer circumferential surface of the central shaft.

18. 18. The rotor bracket of claim 17, wherein the material-saving grooves are spaced apart along the axis of the central shaft.

19. 20. The rotor bracket of claim 18, wherein a plurality of said material-saving grooves are equally spaced along an axis of said central shaft.

20. 20. The rotor bracket of claim 18, wherein the material-saving grooves are disposed along an axis of the central shaft in a denser arrangement in number at the front and a sparser arrangement at the rear.

21. A rotor assembly comprising a rotor bracket and a magnetic body, the rotor bracket being the rotor bracket described in claim 1, the magnetic body being fixedly installed within the accommodating groove, the magnetic body covering a portion of the material-saving groove, and the magnetic body and a bottom wall surface of the material-saving groove being installed with a gap therebetween.

22. The rotor assembly according to claim 21, characterized in that the accommodating groove extends along the axis of the central shaft, has an elongated shape, and penetrates the front end surface and / or the rear end surface of the mounting portion, and the magnetic body is assembled in the accommodating groove along the axial direction.

23. The rotor assembly according to claim 22, wherein a plurality of the magnetic bodies are arranged in each of the receiving grooves and are joined together along the axial direction.

24. 22. The rotor assembly according to claim 21, wherein a seam between two adjacent magnetic bodies in a direction extending along an axis of the central shaft is offset from the material-saving groove.

25. The rotor assembly of claim 23, characterized in that the axial length of the magnetic body is greater than the axial length of the accommodating groove, and the magnetic body protrudes axially beyond the front end surface and / or rear end surface of the mounting portion.

26. 23. The rotor assembly of claim 22, further comprising a filler disposed within the material saving groove, the filler having a density less than a density of the mounting portion.

27. 22. The rotor assembly of claim 21, further comprising a filler disposed within the material saving groove, the filler having a density less than a density of the mounting portion.

28. 28. The rotor assembly of claim 27, wherein an outer surface of the magnetic body protrudes beyond an outer circumferential surface of the mounting portion, and an outer surface of the filler is flush with the outer circumferential surface of the mounting portion.

29. 28. The rotor assembly of claim 27, wherein the filler is an adhesive that fixedly connects the magnetic body and the mounting portion.

30. A rotor assembly comprising a rotor bracket and a magnetic body, the rotor bracket being the rotor bracket described in claim 2, the magnetic body being fixedly installed within the accommodating groove, the magnetic body covering a portion of the material-saving groove, and the magnetic body and a bottom wall surface of the material-saving groove being installed with a gap therebetween.

31. A rotor assembly comprising a rotor bracket and a magnetic body, the rotor bracket being the rotor bracket described in claim 9, characterized in that the magnetic body is fixedly installed within the accommodating groove, the magnetic body covers a portion of the material-saving groove, and the magnetic body and a bottom wall surface of the material-saving groove are installed with a gap therebetween.

32. A rotor assembly comprising a rotor bracket and a magnetic body, the rotor bracket being the rotor bracket described in claim 15, the magnetic body being fixedly installed within the accommodating groove, the magnetic body covering a portion of the material-saving groove, and the magnetic body and a bottom wall surface of the material-saving groove being installed with a gap therebetween.

33. 22. A motor comprising a motor case, a stator assembly, and a rotor assembly, the rotor assembly being the rotor assembly of claim 21.

34. 34. The motor of claim 33, further comprising a sensing assembly, the sensing assembly including a circuit board and a plurality of Hall sensors electrically connected to the circuit board, the Hall sensors coupled to magnetic marks on the rotor assembly.

35. 35. The motor of claim 34, wherein the detection assembly is provided at a rear end of the motor case, the motor case is provided with a lead hole between the detection assembly and the stator assembly, and the lead hole is used to pull out leads of the detection assembly and the stator assembly from the motor case.

36. 23. A motor comprising a motor case, a stator assembly, and a rotor assembly, the rotor assembly being the rotor assembly of claim 22.

37. 34. An electric toothbrush comprising a handle, a motor, and a brush head, the motor being mounted in an internal cavity of the handle, a central shaft of the rotor assembly extending from an end of the handle, and the brush head being attached to the end of the central shaft, the motor being the motor described in claim 33.

38. An electric toothbrush comprising a handle, a motor and a brush head, the motor being mounted in an internal cavity of the handle, a central shaft of the rotor assembly extending from an end of the handle, and the brush head being attached to the end of the central shaft, the motor being the motor described in claim 34.

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