CN215956126U - Low-heating high-efficiency motor for electric toothbrush - Google Patents

Abstract

The utility model provides a motor for an electric toothbrush with low heating and high efficiency, which comprises a shell, a stator iron core, a coil winding, a motor shaft and a permanent magnet component, wherein the stator iron core comprises an iron core main body matched with the permanent magnet component and an iron core magnetizer in magnetic conduction fit with the iron core main body, and the iron core magnetizer comprises a coil winding part which extends straightly; the coil winding is wound on the coil winding part and extends straightly along the axial direction vertical to the motor shaft; along the axial of motor shaft, the length of coil winding portion in the iron core magnetizer is less than the length of iron core main part, and the length ratio of both is less than 0.6. This application does the coil winding portion short, but the cross-section is unchangeable, has guaranteed the same ampere of turns and magnetic resistance, can reduce the single turn girth of coil winding under the prerequisite that provides the same magnetic flux to effectively reduce the resistance and generate heat, also reduce the generating heat of motor for electric toothbrush, finally improve the efficiency of motor for electric toothbrush.

Description

Low-heating high-efficiency motor for electric toothbrush

Technical Field

The utility model relates to a motor, in particular to a motor for an electric toothbrush with low heat generation and high efficiency.

Background

The electric toothbrush mainly comprises a motor (namely a motor) and a brush head, wherein the brush head generates high-frequency vibration through the rapid operation of the motor, so that toothpaste is instantly decomposed into fine foam to deeply clean teeth gaps; meanwhile, the vibration of the brush hair on the brush head can promote the blood circulation in the oral cavity, and has a certain massage effect on the gum tissue. Thus, the motor is a major component of the electric toothbrush.

Further, the motor for the electric toothbrush at present mainly includes a stator portion and a rotor portion; the stator part comprises a shell, a stator core and a coil winding, wherein the stator core and the coil winding are both fixed on the shell; the rotor part comprises a motor shaft which is rotatably supported in the shell through a bearing, and a permanent magnet which is fixed on the outer surface of the motor shaft; the stator core is matched with the permanent magnet. However, the stator core in the motor for the conventional electric toothbrush is an integral piece; in addition, in order to ensure certain performance of the motor for the electric toothbrush, the permanent magnet is generally slender along the axial direction of a motor shaft, and a stator iron core matched with the permanent magnet has the same length as the permanent magnet, so that the stator iron core is also slender; for example, a small-sized high-frequency vibration device disclosed in the chinese utility model patent with the publication number CN 203967899U; for example, the ultrasonic vibration motor disclosed in the chinese utility model patent with the publication number CN 207321079U. Therefore, the single-turn circumference of the coil winding wound on the stator core is inevitably larger, namely, the single-turn section of the coil winding is larger, so that the resistance is directly serious in heating, and the motor for the electric toothbrush is low in efficiency and difficult to improve.

SUMMERY OF THE UTILITY MODEL

In view of the above-mentioned drawbacks of the prior art, it is an object of the present invention to provide a motor for an electric toothbrush with low heat generation and high efficiency, which can reduce the circumference of a single turn of a coil winding while maintaining a constant cross section of a stator core.

In order to achieve the above object, the present invention provides a motor for an electric toothbrush with low heat generation and high efficiency, comprising a housing, a stator core and a coil winding both fixed to the housing, a motor shaft rotatably supported in the housing, and a permanent magnet part fixed to the motor shaft, wherein the stator core comprises a core body distributed at the periphery of the permanent magnet part and cooperating with the permanent magnet part, and a core magnetizer in magnetic conductive cooperation with the core body, the core magnetizer comprises a coil winding part extending straightly, the coil winding is wound on the coil winding part, and the coil winding extends straightly in an axial direction perpendicular to the motor shaft; along the axial direction of the motor shaft, the length of a coil winding part in the iron core magnetizer is smaller than that of the iron core main body, and the length ratio of the coil winding part to the iron core main body is smaller than 0.6.

Furthermore, the iron core magnetizer further comprises a bending part integrally extending from the end part of the coil winding part, and one end of the bending part, far away from the coil winding part, extends to the iron core main body and is in contact fit or clearance fit with the iron core main body; and along the axial direction of the motor shaft, the length of a coil winding part in the iron core magnetizer is the same as that of the bending part.

Further, along the axial of motor shaft, the iron core magnetizer distributes in the intermediate position of iron core main part.

Further, the shell includes first casing and the second casing of arranging relatively along the motor shaft axial and distributes the middle casing between first casing and second casing, first casing and second casing are fixed to link to each other, the both ends of middle casing are fixed with first casing and second casing respectively and are linked to each other, the iron core main part is fixed in first casing, iron core magnetizer and coil winding all are fixed in middle casing.

Furthermore, the middle shell, the iron core magnetizer and the coil winding are fixed into an independent prefabricated part.

Furthermore, the middle shell is made of plastic, and the middle shell is fixed on the periphery of the bending part in the iron core magnetizer in an injection molding mode.

Furthermore, two ends of the middle shell are provided with first inserting convex parts protruding outwards along the axial direction of the motor shaft, first connecting grooves are formed in the first shell and the second shell, and the first inserting convex parts are inserted into the first connecting grooves in a tight fit mode.

Furthermore, the first shell and the second shell are both made of plastics.

As described above, the motor for an electric toothbrush according to the present invention has the following advantageous effects:

in the application, after the stator iron core is provided with the iron core main body and the iron core magnetizer with different lengths, the coil winding part for winding the coil winding in the iron core magnetizer can be shortened, and the stator iron core does not need to be slender as the iron core main body; and the length of the coil winding directly determines the circumference and cross-sectional size of a single turn of the coil winding. According to the theory of magnetism, when the total length of a magnetic path is unchanged, the magnetomotive force generated by a coil winding is in direct proportion to the ampere-turn Number (NI), the magnetic resistance is in inverse proportion to the sectional area, and the magnetic flux generated by the coil winding is equal to the magnetomotive force divided by the magnetic resistance. So, this application does the coil winding portion short, but the cross-section is unchangeable, has guaranteed same ampere of turns and magnetic resistance, can reduce the single turn girth of coil winding under the prerequisite that provides the same magnetic flux to effectively reduce the resistance and generate heat, also reduce the generating heat of motor for the electric toothbrush, finally improve the efficiency of motor for the electric toothbrush.

Drawings

Fig. 1 is a schematic view showing a structure of a motor for an electric toothbrush according to the present application.

Fig. 2 is a top view of fig. 1.

Fig. 3 is a sectional view taken along line a-a of fig. 2.

Fig. 4 to 6 are schematic structural views of the motor for an electric toothbrush according to the present invention without a housing.

Fig. 7 is a schematic structural diagram of a preform composed of an intermediate case, core conductors, and coil windings in the present application.

Fig. 8 is a schematic structural view of the first housing and the core main body after assembly in the present application.

Fig. 9 is a schematic structural diagram of a second housing in the present application.

Description of the element reference numerals

10 outer casing

11 first casing

111 first mounting groove

112 first connecting groove

113 mounting card slot

114 shell end

115 casing body

116 second plug-in lug

12 second casing

121 second mounting groove

122 second connecting groove

13 middle shell

131 first inserting convex part

20 stator core

21 iron core body

211 arc segment

212 horizontal segment

213 vertical segment

22 iron core magnetizer

221 coil winding part

222 bending part

30 coil winding

40 Motor shaft

50 permanent magnet component

51 permanent magnet

60 first bearing

70 second bearing

80 Flexible member

Detailed Description

The following description of the embodiments of the present invention is provided for illustrative purposes, and other advantages and effects of the present invention will become apparent to those skilled in the art from the present disclosure.

It should be understood that the structures, proportions, and dimensions shown in the drawings and described herein are for illustrative purposes only and are not intended to limit the scope of the present invention, which is defined by the claims, but rather by the claims. In addition, the terms such as "upper", "lower", "left", "right", "middle" and "one" used in the present specification are for convenience of description only and are not intended to limit the scope of the present invention, and changes or modifications of the relative relationship thereof may be made without substantial technical changes and modifications.

The application provides a motor for an electric toothbrush with low heat generation and high efficiency, which is used for the electric toothbrush. As shown in fig. 1 to 3, the motor for an electric toothbrush according to the present application includes a housing 10, a stator core 20, a coil winding 30, a motor shaft 40, and a permanent magnet member 50; wherein, the stator core 20 and the coil winding 30 are fixed to the case 10; the motor shaft 40 is rotatably supported in the housing 10 by a bearing, the motor shaft 40 being made of a magnetically conductive material; the permanent magnet part 50 is provided on the outer circumference of the motor shaft 40. For convenience of description, in the present embodiment, the axial direction of the motor shaft 40 is defined as the forward and backward direction.

Further, as shown in fig. 4 to 6, the stator core 20 includes core main bodies 21 distributed on the outer periphery of the permanent magnet member 50 and engaged with the permanent magnet member 50, and core magnetizers 22 magnetically conductively engaged with the core main bodies 21. In the views shown in fig. 4 to 6, the permanent magnet part 50 is provided with a pair; accordingly, the core main bodies 21 in the stator core 20 are also arranged in a pair, one for one, in correspondence with the permanent magnet members 50. In addition, each permanent magnet member 50 is bipolar, having an N pole and an S pole; namely: each permanent magnet part 50 comprises two permanent magnets 51 with different polarities, and the two permanent magnets 51 forming each permanent magnet part 50 are arranged in a close manner along the circumferential direction of the motor shaft 40 and extend along the axial direction of the motor shaft 40, so that the permanent magnets 51 are in a slender strip-shaped structure; the two permanent magnet parts 50 connected have a gap therebetween in the circumferential direction of the motor shaft 40.

Further, as shown in fig. 4 to 6, the core main body 21 and the core magnetizer 22 of the stator core 20 are two independent components, that is, the stator core 20 is a split structure, but both the core main body 21 and the core magnetizer 22 constituting the stator core 20 are an integral structure. The iron core main body 21 is Y-shaped, and an end surface of the iron core main body 21 facing the permanent magnet component 50 is an arc surface, or the section of the iron core main body 21 close to the permanent magnet component 50 is an arc section 211; the iron core main body 21 includes, in order from inside to outside, an arc segment 211, a horizontal segment 212 extending horizontally in the left-right direction, and a vertical segment 213 extending vertically in the up-down direction. The core magnetizer 22 includes a coil winding part 221 horizontally extending in the left-right direction, the coil winding 30 is wound on the coil winding part 221 of the core magnetizer 22, and the coil winding 30 extends straight left and right in the axial direction perpendicular to the motor shaft 40; thus, as shown in fig. 3, the length of the coil winding portion 221 in the axial direction of the motor shaft 40 directly determines the circumference and the sectional size of a single turn of the coil winding 30 in the winding direction thereof: the length of the coil winding portion 221 in the axial direction of the motor shaft 40 is long, so that the circumference and the cross section of a single turn of the coil winding 30 are large; the length of the coil winding portion 221 in the axial direction of the motor shaft 40 is short, and the single turn of the coil winding 30 is small in the circumferential length and the cross section. In particular, in the present application, the length of the core main body 21 is the same as or different from the length of the permanent magnet component 50 along the axial direction of the motor shaft 40, but the length of the coil winding portion 221 in the core magnetizer 22 is smaller than the length of the core main body 21, and the length ratio of the two is smaller than 0.6.

When the motor for the electric toothbrush works, alternating current is introduced into the coil winding 30, the iron core magnetizer 22 of the stator iron core 20 generates a magnetic circuit and transmits the magnetic circuit to the iron core main body 21, and magnetic flux generated by the stator iron core 20 interacts with the permanent magnet 51 to convert electric energy into mechanical energy; namely: in the permanent magnet part 50, stator ironUnder the combined action of the core 20 and the coil winding 30, the motor shaft 40 is driven to swing, and the brush head is fixed on the motor shaft 40, so that the motor shaft 40 drives the brush head of the electric toothbrush to swing rapidly. During operation, the stator core 20 has resistive heating: q ═ I²R, the resistance R per turn of the stator core 20 is proportional to the circumference of a single turn of the coil winding 30. After the stator core 20 is provided with the split type core main body 21 and the core magnetizer 22 which are different in length, the coil winding part 221 for winding the coil winding 30 in the core magnetizer 22 can be shortened, and the stator core does not need to be slender as the core main body 21; and the length of the coil-winding portion 221 directly determines the circumference and the sectional size of a single turn of the coil winding 30. In addition, according to the theory of magnetism, when the total length of the magnetic path is not changed, the magnetomotive force generated by the coil winding 30 is in direct proportion to the ampere-turn Number (NI), the magnetic resistance is in inverse proportion to the sectional area, and the magnetic flux generated by the coil winding 30 is equal to the magnetomotive force divided by the magnetic resistance. So, this application does coil winding portion 221 short, but the cross-section is unchangeable, has guaranteed the same ampere of turns and magnetic resistance, can reduce the single turn girth of coil winding 30 under the prerequisite that provides the same magnetic flux, just also reduces every turn resistance R of stator core 20 to effectively reduce the resistance of stator core 20 and generate heat under the prerequisite of guaranteeing that the magnetic flux is the same, also reduce the generating heat of motor for electric toothbrush, finally improve the efficiency of motor for electric toothbrush. In addition, the present invention is configured with only one coil winding 30 on one side of the motor shaft 40, which effectively reduces the cost while ensuring the performance advantage of the motor for the electric toothbrush, and is also beneficial to reducing the size of the motor for the electric toothbrush.

Further, the structure of magnetic conduction between the core body 21 and the core magnetizer 22 is: as shown in fig. 3 to 6, the core magnetizer 22 further includes a bending portion 222 extending from the left and right ends of the coil winding portion 221 to a direction close to the core body 21, and one end of the bending portion 222 away from the coil winding portion 221 extends to the vertical section 213 of the core body 21 and is in contact fit or clearance fit with the vertical section 213 of the core body 21, so that the magnetic conductive fit between the core magnetizer 22 and the two core bodies 21 is realized. Of course, in other embodiments, a bent portion that extends to the coil winding portion 221 and is in contact fit or clearance fit with the coil winding portion 221 may be provided on the core main body 21.

Preferably, as shown in fig. 4 to 6, in the axial direction of the motor shaft 40, the length of the coil winding portion 221 in the core magnet 22 is the same as that of the bending portion 222, that is, the entire core magnet 22 has the same length in the front-rear direction; the length of the circular arc section 211, the length of the horizontal section 212, and the length of the vertical section 213 in the core main body 21 are the same, that is, the core main body 21 as a whole has the same length in the front-rear direction. In addition, in the axial direction of the motor shaft 40, the core magnet 22 is distributed at the middle position of the core main body 21, so that the front end of the core main body 21 is located at the front side of the core magnet 22, and the rear end of the core main body 21 is located at the rear side of the core magnet 22.

Further, as shown in fig. 1 to 3, the casing 10 includes a first casing 11 and a second casing 12 that are arranged along the axial direction of the motor shaft 40, and a middle casing 13 that is distributed between the first casing 11 and the second casing 12, the first casing 11 and the second casing 12 are fixedly connected, the front end and the rear end of the middle casing 13 are respectively fixedly connected with the first casing 11 and the second casing 12, the core main body 21 is fixed to the first casing 11, and the core magnetizer 22 and the coil winding 30 are both fixed to the middle casing 13. Preferably, the first housing 11, the second housing 12 and the middle housing 13 are made of plastic, and the first housing 11, the second housing 12 and the middle housing 13 are injection-molded parts and are also integrally formed parts, which is beneficial to reducing cost and facilitating assembly.

Preferably, the fixing manner between the core magnetizer 22 and the intermediate shell 13 may be: firstly, respectively processing and then gluing and fixing; secondly, the intermediate shell 13 is directly encapsulated and fixed in the injection molding process of the intermediate shell 13, that is, the intermediate shell 13 is directly fixed on the periphery of the bending part 222 in the iron core magnetizer 22 in an injection molding mode. In addition, as shown in fig. 7, the middle housing 13, the core magnetizer 22 and the coil winding 30 are fixed as an independent prefabricated member, which is convenient for winding the coil winding 30 and processing, assembling and maintaining the motor for the electric toothbrush; when assembling the motor for the electric toothbrush, the intermediate housing 13 in the preform may be directly and fixedly connected to the first housing 11 and the second housing 12, respectively.

Further, as shown in fig. 1 and 8, the first housing 11 includes a housing end 114, and a housing main body 115 extending straight and rearward from a rear end of a lower side of the housing end 114, the housing main body 115 extends to a front end surface of the second housing 12, and the two are connected by plugging, and the housing main body 115 includes a bottom portion located at a lower side of the motor shaft 40, and side portions located at left and right sides of the motor shaft 40. An installation empty area is formed between the casing end 114 of the first casing 11 and the second casing 12, the installation empty area is located at the upper side of the motor shaft 40, a prefabricated member formed by assembling the middle casing 13, the core magnetizer 22 and the coil winding 30 is accommodated in the installation empty area, the front end of the middle casing 13 is connected with the casing end 114 of the first casing 11 in an inserting manner, and the rear end of the middle casing 13 is connected with the second casing 12 in an inserting manner. Specifically, as shown in fig. 7 to 9, the front end and the rear end of the middle housing 13 are provided with first insertion protrusions 131 protruding outward along the axial direction of the motor shaft 40, and the rear end surface of the housing end 114 of the first housing 11 and the front end surface of the second housing 12 are provided with first connecting grooves 112; the first inserting convex part 131 at the front end of the middle shell 13 is inserted into the first connecting groove 112 at the shell end part 114 of the first shell 11 in a tight fit manner, so that the prefabricated part and the first shell 11 are fixed; the first insertion protrusion 131 at the rear end of the middle housing 13 is inserted into the first connection groove 112 of the second housing 12 with a tight fit, and fixes the preform to the second housing 12. A second inserting convex portion 116 protruding outward backward is disposed on a rear end surface of the case main body 115 of the first case 11, a second connecting groove 122 is disposed on a front end surface of the second case 12, and the second inserting convex portion 116 on the first case 11 is inserted into the second connecting groove 122 of the second case 12 in a tight fit manner, so as to fix the first case 11 and the second case 12 together. As shown in fig. 8, a mounting slot 113 is opened in a side portion of the housing main body 115 of the first housing 11, a cross-sectional shape of the mounting slot 113 is matched with a cross-sectional shape of the core main body 21, the mounting slot 113 penetrates rearward through the side portion of the housing main body 115, and the core main body 21 is inserted into the mounting slot 113 from a rear end of the housing main body 115, thereby fixing the core main body 21 in the housing main body 115.

Further, as shown in fig. 3, the bearing for rotatably supporting the motor shaft 40 in the housing 10 has two first bearings 60 and second bearings 70 arranged in the front-rear direction, respectively, and the motor shaft 40 is rotatably supported in the first housing 11 through the first bearings 60 and the motor shaft 40 is rotatably supported in the second housing 12 through the second bearings 70. Specifically, the outer end of the housing end 114 of the first housing 11 facing away from the second housing 12 is provided with a first mounting groove 111, the outer end of the first mounting groove 111 penetrates the first housing 11 forward, the first bearing 60 is accommodated in the first mounting groove 111, the inner ring of the first bearing 60 is fixedly connected with the motor shaft 40, and the groove bottom of the inner end of the first mounting groove 111 stops the first bearing 60; the outer end of the second housing 12, which is opposite to the first housing 11, is provided with a second mounting groove 121, the outer end of the second mounting groove 121 penetrates the second housing 12 backwards, the second bearing 70 is accommodated in the second mounting groove 121, the inner ring of the second bearing 70 is fixedly connected with the motor shaft 40, and the groove bottom at the inner end of the second mounting groove 121 stops the second bearing 70. When the motor shaft 40 and the first housing 11 are assembled, the motor shaft 40 is inserted into the inner hole of the first housing 11, and the first bearing 60 is knocked into the first mounting groove 111 of the first housing 11 from the front end of the motor shaft 40 toward the rear until the first bearing 60 abuts against the groove bottom of the first mounting groove 111, whereby the first housing 11 is pressed inward by the first bearing 60. Similarly, when the motor shaft 40 and the second housing 12 are assembled, the motor shaft 40 is inserted into the inner hole of the second housing 12, and the second bearing 70 is driven forward from the rear end of the motor shaft 40 into the second mounting groove 121 of the second housing 12 until the second bearing 70 abuts against the groove bottom of the second mounting groove 121, so that the second housing 12 is pressed inward by the second bearing 70. In this way, after the first bearing 60 and the second bearing 70 are mounted, the first housing 11 and the second housing 12 are clamped and connected in the front-rear direction by the fastening force of the inner race of the first bearing 60 and the motor shaft 40 and the fastening force of the inner race of the second bearing 70 and the motor shaft 40, so that the first bearing 60 and the second bearing 70 are assembled from the outside of the housings, and the first housing 11 and the second housing 12 are clamped, thereby achieving the packaging of the product. Moreover, when the motor shaft 40 and the first housing 11, and the motor shaft 40 and the second housing 12 are assembled, only the first bearing 60 needs to be knocked in from the outer side of the first housing 11 and the second bearing 70 needs to be knocked in from the outer side of the second housing 12 correspondingly, so that the product can be packaged and the bearings are installed for one-step riveting, the installation process is saved, and the assembly efficiency is improved.

Preferably, the inner race of the first bearing 60 is riveted or adhesively fixed to the motor shaft 40, and the inner race of the second bearing 70 is riveted or adhesively fixed to the motor shaft 40.

Further, as shown in fig. 3, in the axial direction of the motor shaft 40, a flexible member 80 having elasticity is provided between the inner end of the first bearing 60 and the first housing 11, where the flexible member 80 is appropriately compressed to generate a forward force; alternatively, a flexible member 80 having elasticity is provided between the inner end of the second bearing 70 and the second housing 12, where the flexible member 80 is compressed properly to generate a backward force; alternatively, the flexible members 80 having elasticity are provided between the inner end of the first bearing 60 and the first housing 11, and between the inner end of the second bearing 70 and the second housing 12. The flexible member 80 is a silicone ring or a washer made of other elastic materials, and realizes flexible support at the first bearing 60 and the second bearing 70. In this way, when the outer ring of the first bearing 60 and/or the second bearing 70 is subjected to a force alternately in the forward-backward direction Z, the flexible member 80 can eliminate the Z-directional play of the first bearing 60 and/or the second bearing 70, thereby eliminating the running noise of the first bearing 60 and/or the second bearing 70. In addition, when the motor shaft 40 is subjected to a Z-direction impact force during falling, the flexible member 80 can buffer the impact force, and plays a certain role in protection.

In conclusion, the present invention effectively overcomes various disadvantages of the prior art and has high industrial utilization value.

The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the utility model. Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.

Claims (8)

1. A motor for an electric toothbrush with low heat generation and high efficiency, comprising a housing (10), a stator core (20) and a coil winding (30) both fixed to the housing (10), a motor shaft (40) rotatably supported in the housing (10), and a permanent magnet member (50) fixed to the motor shaft (40), characterized in that: the stator core (20) comprises a core main body (21) which is distributed on the periphery of the permanent magnet part (50) and matched with the permanent magnet part (50), and a core magnetizer (22) which is in magnetic conduction fit with the core main body (21), wherein the core magnetizer (22) comprises a coil winding part (221) which extends straightly, the coil winding (30) is wound on the coil winding part (221), and the coil winding (30) extends straightly along the axial direction which is perpendicular to the motor shaft (40); along the axial direction of the motor shaft (40), the length of a coil winding part (221) in the iron core magnetizer (22) is smaller than that of the iron core main body (21), and the length ratio of the two is smaller than 0.6.

2. The motor for an electric toothbrush according to claim 1, wherein: the iron core magnetizer (22) further comprises a bending part (222) integrally extending from the end part of the coil winding part (221), and one end, far away from the coil winding part (221), of the bending part (222) extends to the iron core main body (21) and is in contact fit or clearance fit with the iron core main body (21); the length of a coil winding part (221) in the iron core magnetizer (22) is the same as that of the bending part (222) along the axial direction of the motor shaft (40).

3. The motor for an electric toothbrush according to claim 1 or 2, characterized in that: the iron core magnetizer (22) is distributed at the middle position of the iron core main body (21) along the axial direction of the motor shaft (40).

4. The motor for an electric toothbrush according to claim 1, wherein: the motor is characterized in that the shell (10) comprises a first shell (11) and a second shell (12) which are oppositely arranged along the axial direction of the motor shaft (40) and an intermediate shell (13) which is distributed between the first shell (11) and the second shell (12), the first shell (11) and the second shell (12) are fixedly connected, two ends of the intermediate shell (13) are fixedly connected with the first shell (11) and the second shell (12) respectively, the iron core main body (21) is fixed on the first shell (11), and the iron core magnetizer (22) and the coil winding (30) are fixed on the intermediate shell (13).

5. The motor for an electric toothbrush according to claim 4, wherein: the middle shell (13), the iron core magnetizer (22) and the coil winding (30) are fixed into an independent prefabricated part.

6. The motor for an electric toothbrush according to claim 4, wherein: the middle shell (13) is made of plastic, and the middle shell (13) is fixed on the periphery of a bending part (222) in the iron core magnetizer (22) in an injection molding mode.

7. The motor for an electric toothbrush according to claim 4, wherein: the motor shaft structure is characterized in that first inserting convex parts (131) protruding outwards along the axial direction of the motor shaft (40) are arranged at two ends of the middle shell (13), first connecting grooves (112) are formed in the first shell (11) and the second shell (12), and the first inserting convex parts (131) are inserted into the first connecting grooves (112) in a tight fit mode.

8. The motor for an electric toothbrush according to claim 4, wherein: the first shell (11) and the second shell (12) are made of plastics.

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